CULTIVATED RUBIACEAE[1]

Cultivated Rubiaceae taxa seen in Thailand fall into 2 categories: 1. ornamental plants, and 2. plants of major or minor commercial value (“cash crops”).

Ornamental plants are either (A) native Thai plants taken into cultivation (the minority) or (B) non-indigenous species (or cultivars) (the majority). Group (B) contains (Ba) exotic species of genera that also have native Thai taxa and (Bb) species of genera that do not naturally occur in Thailand.
In the keys and in the text below,
"#" preceding a name always indicates that the taxon is not indigenous.

Key to cultivated taxa

1. Perennial herbs, sometimes a little woody at base

#Pentas lanceolata cultivars

1*. Shrubs or small trees

2

2. At least some flowers of an inflorescence with enlarged, colored calyx lobes

3

2*. Flowers without enlarged, colored calyx lobes

6

3. All flowers of an inflorescence with enlarged calyx lobes

4

3*. Only some flowers (often not more than 4) of an inflorescence with enlarged, leaf-like, colored calyx lobes (“show calyx leaves”) []

5

4. Flowers with bright red, enlarged, unequal calyx lobes (1 more enlarged than the others); fruit indehiscent, hard, nut-like, crowned by the persistent enlarged calyx lobes

#Carphalea kirondron

4*. Flowers with not markedly unequal, distinctly stalked, enlarged white to pink or pinkish-red calyx leaves [-fig. C]; fruit berry-like, with leathery skin (usually not developed)

#Mussaenda philippica cultivars

5. Show calyx leaves bright red; inflorescence axes, ovaries, small calyx lobes and exterior of the corolla tubes with indumentum of the same colour; corolla white to creamy-white, with a dark-red “eye” in the centre (i.e. a ring of dark-red hairs surrounding the corolla throat); fruit indehiscent, berry-like, with a leathery skin

#Mussaenda erythrophylla

5*. Show calyx leaves white to creamy-yellow; corolla yellow, the throat often with a ring of lemon- to orange-yellow hairs; fruit dry, dehiscent, capsular, 2-valved

#Pseudomussaenda flava

6. Inflorescence terminal, many-flowered

7

6*. Inflorescences axillary (and often many-flowered) or terminal (sometimes on much contracted shoots) and few- to 1-flowered

12

7. Inflorescence a pedunculate, globose many-flowered head

Mitragyna speciosa

7*. Inflorescence not as above

 8

8. Corolla bright red or orange-red, with a conspicuous yellow(-orange) “eye” the center; leaves thick-leathery, bullate

#Rondeletia odorata

8*. Corolla variously coloured, never with a conspicuous yellow(-orange) “eye” the center; leaves never bullate

 9

9. Inflo­rescences consisting of double-helicoid cymes with sessile flowers; corolla yellow to yellow-orange or orange-red, rather thick and robust, tube cylindrical, with a swollen base, lobes erect; anthers, styles and 5-lobed stigmas always included

 #Hamelia patens

9*. Inflorescences and flowers not as above

10

10.  Small trees; corolla lobe margins densely beset with long spreading hairs; fruit a 2-valved capsule; seeds laterally flattened, with a large, fimbriate bipolar wings

#Cinchona calisaya

10*. Shrubs; corolla lobe margins not hairy; fruits either indehiscent and fleshy or dry and capsular, but then not with flattened, winged seeds

11

11. All all vegetative parts foetid when bruised; flowers 5-merous; fruits capsular, 5-valved, seeds enclosed by net-like structure

#Spermadictyon suaveolens

11*. Plant not foetid; flowers 4-merous; fruits fleshy, indehiscent

 Ixora (native and exotic ornamentals and cultivars) [go to separate Ixora key, below]

12. Inflorescences paired, in leaf axils, consisting of several- to many-flowered congested to lax cymes

 13

12*. Inflorescence few- to 1-flowered, mostly terminal on sometimes much-contracted shoots

16

13. Flowers white, quite large, showy, 4-9-merous; calyx ring-like, minute, often with small indistinct teeth; ovary 2-celled; fruit an ellipsoidal to globose red drupe with 2 one-seeded, thin-walled pyrenes; seeds plano-convex, with a slightly curved fold on the flat ven­tral side

 14 [Coffea]

13*. Flowers greenish-yellow, pale yellowish or cre­amy-white, small; calyx with distinct spreading to recurved lobes; ovary 5-celled; fruit a large globose drupe with 5 thick-walled pyrenes

 #Vangueria madagascariensis

14. Stipules triangular-ovate, obtuse at apex, small, only to 4 mm long; not so widely cultivated, and usually not on a large scale

 #Coffea liberica [Liberica Coffee]

14*. Stipules triangular to deltoid, acute at apex, or at least with an apical mucro, usually much longer (to 8 or 16 mm long, respectively); cultivated on a large scale (plantations!)

15

15. Leaves to 35(40) cm long, with (8)11-15(17) pairs of lateral veins; flowers in axillary clusters of 8-30(50); stipules to 18 mm long; fruits broadly oblong-ellipsoid, 10-15 by 5-12 mm; normally cultivated at low altitudes

#Coffea canephora [Robusta Coffee]

15*. Leaves to 15(18) cm long, with 7-10 pairs of lateral veins; stipules to 8 mm long; flowers in axillary clusters of 2-20; fruits oblong-ellipsoid to subglobose, 10-20 by 10-12 mm; normally cultivated from c. 800 m upwards

 #Coffea arabica [Arabica Coffee]

16. Leaf and stem tissue emitting a bad smell when crushed; flowers not fragrant, heterostylous (either anther or style plus stigmas exserted), corolla lobes valvate-induplicate in bud, distinctly tripartite at apex; often grown as bonsai

#Serissa japonica cultivars

16*. Plants without a bad small; flowers often fragrant, not heterostylous; corolla lobes contorted in bud, not tripartite at apex

17

17. Flowers 5-merous, produced before or with new leaves, fragrant; calyx indistinct, with minute teeth; corolla white, with a narrow, cylindrical tube to 22 mm long

 Psilanthus bengalensis

17*. Flowers 6(-9)-merous, produced on leafy plants, fragrant or not; calyx with distinct lobes; corolla white or yellowish(-orange), tube sometimes much longer

18 [Gardenia, cultivated taxa]

18. Calyx with 6(-9) linear-lanceolate spur-like lobes; corolla often double [6(-9) true (outer) lobes and more numer­ous, smaller inner lobes (= petaloid, sterile stamens)]

#Gardenia jasminoides

18*.  Calyx not as above; double-flowered forms unknown

Gardenia (cultivated indigenous spp.)

1. Ornamental plants

#Carphalea Juss.

A genus of 10 species, occurring naturally in Africa and Madagascar; 1 Madagascan species cultivated in Thailand:

#Carphalea kirondron Baill., Bull. Mens. Soc. Linn. Paris 1: 188. 1878; Puff, Bull. Jard. Bot. Nat. Belg. 58: 300. 1988.

Shrubs to 3 m tall (much taller and becoming tree-like if allowed to grow). Leaves decussate (occasionally in whorls of 3), membranous, petiolate; stipules connate below, free parts 3–5 fimbriate. Inflorescence terminal, a many-flowered, corymb-like thyrse. Flowers mostly 4-merous, heterostylous. Calyx lobes enlarged, unequal (1 more enlarged than the others), bright red. Corolla tube narrowly cylindrical, reddish outside, lobes valvate in bud, spreading-recurved in open flowers, (creamy-)white. Stamens inserted below or around throat; anthers on long filaments, exserted in short-styled, included in long-styled morphs. Ovary 2-celled, each locule with a few ovules on a peltate placenta; style with 2-lobed stigma included in short-styled, exserted in long-styled morphs. Fruits indehiscent, nut-like, obconic, crowned by the persistent enlarged calyx lobes; typically only 1 fertile seed in each locule, but not one or both seeds aborted.

Apparently a fairly recent introduction (possibly from the Singapore Botanic Garden) which seems to have become more popular in recent years. Confirmed sightings from Chiang Mai, Kanachanaburi and Songkla Provinces and Bangkok. Difficulties in propagation (low seed germination rate; vegetative propagation by cuttings is often not successful) may restrict its wider distribution as an ornamental.

Gardenia Ellis

See page 000-000 for details on the genus. Several species (both indigenous and exotic) are grown in Thailand as ornamentals. For indigenous cultivated species (Gardenia carinata , G. coronaria  and G. sootepensis) see page 000, 000 and 000 respectively. The most widely cultivated and possibly only non-indigenous species, naturally occurring in China, Taiwan, and Japan, is:

#Gardenia jasminoides J.Ellis, Philos. Trans. 51(2): 935. 1761.— Gardenia florida L., Sp. Pl. ed. 2: 305. 1762, nom. illeg.— Gardenia augusta Merr., Interpr. Herb. Amboin.: 485. 1917, nom. superfl.; Craib in Fl. Siam. En. 2(1): 115. 1932.

 Shrubs ca. 1–2 m tall. Leaves decussate or occasionally in whorls of 3, coriaceous, glossy, shortly petiolate; stipules sheathing above the insertion of the peti­oles. Inflorescences consisting of solitary flowers terminal on abbreviated lateral shoots (thus often seemingly axillary). Flowers 6(-9)-merous, fragrant, hermaphrodite or sterile (double-flowered forms). Calyx with 6(-9) linear-lanceolate spur-like lobes. Corolla white, often double and then consisting of 6(-9) true (outer) lobes and more numer­ous, smaller inner lobes (= petaloid, sterile stamens). Stamens (in fertile flowers) with the subsessile anthers barely exserted from the tube. Ovary 1-celled  in fertile flowers (gynoecium poorly developed in double-flowered forms), style with clavate stigma partially exserted. Fruits crowned by persistent calyx, ovoid, longitudinally ribbed, berry-like, bright orange-reddish, with numer­ous seeds embedded in a fleshy pulp (fertile individuals). Double-flowered forms often pro­ducing seedless “pseudo-fruits” (= enlarged sterile ovaries), smaller than fertile fruits.

The double-flowered cultivar, being much more frequently planted than the “normal”-flow­ered form, can be found everywhere in Thailand. Several other cultivars exist but are not widely grown.

In horticultural literature often known under the incorrect name Gardenia florida. The correct name of this taxon is disputed; there is no general agreement on Gardenia augusta being a superfluous name.

#Hamelia Jacq.

A neotropical genus of 16 species; 1 widely cultivated in Thailand:

#Hamelia patens Jacq., Enum. Syst. Pl.: 16. 1760; Craib in Fl. Siam. En. 2(1): 86. 1932.

Shrubs or, if allowed to grow, small trees to 7 m. Leaves decussate or in whorls of 3 or 4, membranous, petiolate; stipules (narrowly) triangular, caducous. Inflo­rescence terminal, many-flowered, consisting of double-helicoid cymes with sessile flowers; inflorescence axes red. Flowers 5-merous, hermaphrodite. Calyx red, with minute triangular lobes. Corolla yellow to yellow-orange or orange-red, rather thick and robust, tube cylindrical, with a swollen base, lobes imbricate in bud, erect in open flowers. Stamens subsessile, anthers included. Ovary red, 5-celled, each locule with numerous ovules on a peltate placenta attached to the septum; style and 5-lobed stigma included. Fruits berry-like, ellipsoid to globose, yellow to red at first, shiny dark blue-black when fully mature. Seeds numerous, minute.

Widely and for a long time planted all over the country and grown as living fence or hedge or as a solitary bush. Fast-growing and  blooming all year round; soon flowering again after trim­ming and pruning. Individuals left untouched for several years become tree-like but are less attractive in such a state. In Thailand sun birds (but also butterflies) can be observed as pollinators; pollination appears to be highly effective as the rate of fruit set is high (plants are, however, frequently trimmed after a flowering flush so that fruiting individuals are  not often seen).

Ixora L.

See page 000-000 for details on the genus. 11 species (5 indigenous, 6 exotic) and several “varieties” (cultivars) are grown in Thailand as ornamentals.

key to taxa and cultivars of ixora grown as ornamentals

1. Leaves small, usually not more than ca. 5 cm long, mostly not more than 1-2(2.5) cm wide; mostly densely leafy dwarf shrubs, ca. 15 cm to 1 m tall

2

1*. Leaves larger, more than 4 cm wide; taller shrubs or small trees

 3

2. Leaf blade base cordate

12 [#Dwarf Ixora coccinea forms (“Dwarf Coccineas”)]

2*. Leaf blades gradually or rather suddenly narrowed to the base

 #Ixora ‘Sunkist’

3. Inflorescence side axes never opposite, though sometimes subopposite

 Ixora grandifolia

3*. Inflorescence side axes strictly opposite

 4

4. Flowers with very long corolla tubes (60-70 mm), inflorescences ± drooping

 #Ixora hookeri

4*. Flowers with much shorter corolla tubes (to 40 mm at the most), inflorescences erect

 5

5. Calyx lobes 3-5 mm long, at least 2x as long as the basal, tubular part of calyx, oblong-lanceolate, basally overlapping

  Ixora finlaysoniana

5*. Calyx lobes shorter than basal, tubular part of calyx, often narrower; if quite long, then lobes not overlapping basally

 6

6. Leaf blade base cordate

 12 [#Ixora coccinea forms]

6*. Leaf blades narrowed to the base

7

7. Flowers white and fragrant (buds tinged pink)

Ixora cibdela

7*. Flowers in various shades of red, orange or yellow, not fragrant

 8

8. Leaves subsessile to sessile

 #Ixora chinensis

8*. Leaves distinctly petiolate

 9

9. Petioles 10-30 mm long; corolla lobes blunt or ± rounded at the apex

  #Ixora congesta

9*. Petioles 3-10 mm long; corolla lobes acute to subobtuse at the apex

 10

10. Leaf blades with 10-26 pairs of lateral veins (typically more than 15 pairs)

 Ixora lobbii

10*. Leaf blades with less than 10 pairs of lateral veins 

 11

11. Corolla brilliant scarlet red, lobes 1-3 mm wide

 #Ixora macrothyrsa

11*. Corolla mostly orange red but never scarlet, lobes 4-4.5 mm wide

 Ixora javanica

12. Corolla red

13

12*. Corolla shades of pink, white, or yellow (never bright red)

14

13. Corolla lobes lanceolate or narrowly elliptic, 2-8 mm wide, gradually tapering towards the tip; corolla tube 20-35 mm long

#Ixora coccinea var. coccinea & “Dwarf” var. coccinea

13*. Corolla lobes broadly ovate or elliptic, 8-10 mm wide, the tip suddenly pointed; corolla tube 35-40 mm long

#Ixora coccinea var. bandhuca & “Dwarf” var. bandhuca

14. Corolla consistently yellow

#Ixora coccinea var. lutea & “Dwarf” var. lutea

14*. Corolla not yellow (although sometimes yellowish at first)

15

15. Corolla pure white

#Ixora coccinea, white-flowered & “Dwarf”white form

15*. Corolla not pure white

 16

16. Corolla lobes consistently pink

 #Ixora coccinea var. rosea & “Dwarf” var. rosea

16*. Corolla lobes pale pinkish-white (yellowish at first)

#Ixora coccinea var. decolorans & “Dwarf” var. decolorans

Cultivated indigenous species (see page 000-000 for full details, including descriptions):

Ixora cibdela Craib

Only rarely cultivated. Planted specimens appear to have been taken from the wild; probably not sold by commercial nurseries.

Ixora finlaysoniana Wall. ex G.Don

Cultivated all over the country and liked for its white, strongly fragrant flowers, but not as widely used as an ornamental as the I. coccinea cultivars (see below). Robust, white-flowered forms of the latter may superficially resemble I. finlaysoniana but are distinguished by their cordate leaf bases and their much shorter calyx lobes. , detail:

Ixora grandifolia Zoll. & Mor.

Occasionally planted in peninsular Thailand, but not sold on a large scale. Cultivated plants may have been taken from the species’ natural habitat.

Ixora javanica (Blume) DC.

Rather widely cultivated in Thailand, although far less popular as an ornamental than the I. coccinea cultivars (see below). Plants are occasionally sold in markets.

Ixora lobbii King et Gamble

Occasionally planted in peninsular Thailand, but rarely elsewhere. Cultivated plants may have been taken from the wild. Probably not sold by nurseries.

Cultivated exotic species and cultivars:

#Ixora chinensis Lam., Encycl. 3: 344. 1789.

Shrubs to 2(3) m tall. Leaves subsessile to sessile, coriaceous, elliptic, lanceolate-elliptic or narrowly obovate, 5–15 by 2–6 cm, base obtuse, apex acute; nerves 6–10 pairs of lateral veins; stipules 2–3 mm long, the apical awn 1 mm long. Inflorescence corymb-like, often with 3 main branches; inflorescence axes crimson. Flowers not fragrant, shortly pedicellate. Calyx lobes blunt to subacute, 2 mm long. Corolla apricot yellow, turning red with age, tube 30-35 mm long; lobes broadly elliptic or orbicular, blunt at the apex. Fruits globose, 6 – 10 mm in diam., seldom produced.

Widely cultivated all over the country and offered for sale by nurseries. Naturally occurring in S. China and Indochina. Vernacular: Khem Sad เข็มแสด (Bangkok), Khem Laeng เข็มเหลือง (Bangkok).

Often been mistaken for (“normal” forms of) I. coccinea, but the latter is characterized by its cordate to ± amplexicaul leaf blade bases and pointed corolla lobes. Apparently very close to the indigenous and variable I. javanica; the only  reliable distinction character appears to be petiole length (subsessile in I. chinensis and petiolate in I. javanica).

#Ixora coccinea L., Sp. Pl.: 110. 1753.

Shrubs to 3(4) m tall, or dwarf shrubs 0.1-1 m [dwarf forms]. Leaves subcoriaceous, elliptic, to 13 by 7 cm or much smaller, 3.5-5 by 1-2(2.5) cm [dwarf forms], base cordate to ± amplexicaul, apex acuminate or acute; 2–4 pairs of main lateral veins; petiole to 2 mm long; stipules 3–5 mm long, awn 3 mm long. Inflorescence corymbose, sessile or shortly pedunculate, inflorescence axes green. Flowers not fragrant, pedicels 5-8 mm long. Calyx lobes broad, subacute, shorter than ovary. Corolla typically red, but also orange-red, yellow, pink, pinkish-white or white in certain cultivars, tube 20-35 mm long, lobes lanceolate-elliptic, 2–10 mm wide, acute. Fruits globose, 6–15 mm in diam., reddish at first, shiny black when fully mature.

The species, naturally occurring in India, Sri Lanka and Indochina, is probably the most widely planted ornamental in the (wet) tropics, including Thailand. Various cultivars are grown, many of which have been formally recognized as varieties [Corner, Gard. Bull. Str. Settl. 9: 185-186. 1941] although they are hardly more than forms, often only differing in flower color or minor floral differences.

It should be noted that there are basically 2 garden forms of I. coccinea: (1) those with a “normal” shrubby habit and relatively large leaves, and (2) those with a dwarf shrubby and densely leafy habit and small leaves (collectively known as “Dwarf Coccinea” cultivars).

[Ixora coccinea] Var. coccinea

 Shrub to 3(4) m tall. Corolla red, tube 20-35 mm long, lobes lanceolate or narrowly elliptic, 2-8 mm wide, gradually tapering towards the tip.

Widely grown all over Thailand. Vernacular: Khem Daeng เข็มแดง (Bangkok); “Indian Ixora” [Corner 1941].

Dwarf form: Together with “Dwarf Coccinea Bandhuca” (below) the by far most widely planted ornamental Dwarf Ixora in Thailand. Vernacular: Khem เข็ม (Bangkok); “Dwarf Red Coccinea.” -bottom

[Ixora coccinea] Var. bandhuca (Roxb.) Kurz, J. Asiat. Soc. Bengal 46(2): 148. 1877, For. Fl. Burma 2: 27. 1877; Corner, in Gard. Bull. Str. Settl. 9: 185. 1941.— Ixora bandhuca Roxb., Fl. Ind. 1: 386. 1820, Fl. Ind., ed. Carey 1: 376. 1832.

Shrub 3 m tall. Corolla red, tube 35-40 mm long, lobes broadly ovate or elliptic, the tip suddenly pointed, 8-10 mm wide.

With slightly larger flowers than the typical variety but otherwise scarcely different. It might the most commonly grown variety of I. coccinea and is found all over Thailand. Vernacular: Khem Deang เข็มแดง (Bangkok); “Ixora Bandhuca” [Corner 1941].

Dwarf form: Together with “Dwarf Red Coccinea” (above) the by far most widely planted ornamental Dwarf Ixora in Thailand. Vernacular: Khem เข็ม (Bangkok); “Dwarf Coccinea Bandhuca”. -top (detail)

[Ixora coccinea] Var. decolorans Corner, Gard. Bull. Str. Settl. 9: 185. 1941.

Merely a form with relatively unattractive flowers which are yellowish at first and then change to pale pinkish white. Not known from the wild; apparently a cultivar that was developed at and distributed from the Singapore Botanic Gardens. This color form is not very widely grown in Thailand. Vernacular: Khem เข็ม (Bangkok); “Pallid Coccinea” [Corner 1941].

Dwarf form: Because of its less showy flowers, this dwarf form is not so widely planted, although seen scattered all over Thailand. Vernacular: Khem เข็ม (Bangkok); “Dwarf Pallid Coccinea”.

[Ixora coccinea] Var. lutea (Hutchison) Corner in Gard. Bull. Str. Settl. 9: 186. 1941.— Ixora lutea Hutch., Bot. Mag. 138: t. 8439. 1912.— Ixora coccinea L. f. lutea (Hutchison) Fosberg & Sachet, Baileya 23: 79.1989.

Merely a color-form of the typical I. coccinea. The corolla lobes are always yellow (at most changing to pale yellow when old) and never turn reddish or red. Not known from the wild; apparently a cultivar that was developed at and distributed from the Botanic Gardens at Peradeniya, Sri Lanka. This yellow form is very widely cultivated all over Thailand (although not as common as the red-flowered forms). Vernacular: Khem Lueang เข็มเหลือง (Bangkok); “Yellow Coccinea” [Corner 1941].

Dwarf form: Very often cultivated and common all over Thailand. Vernacular:  Khem Lueang เข็มเหลือง (Bangkok); “Dwarf Yellow Coccinea”. Note: This yellow dwarf form should not be confused with the superficially similar looking Ixora “Sunkist”, see further below.

[Ixora coccinea] Var. rosea Corner, Gard. Bull. Str. Settl. 9: 186. 1941.

Merely a form with pink corollas (which neither change color to red nor yellow). Not known from the wild; apparently a cultivar that was developed at and distributed from the Singapore Botanic Gardens. Rather popular and widely cultivated in Thailand (although not as common as the red-flowered forms). Vernacular: Khem chompoo เข็มชมพู (Bangkok); “Pink Coccinea” [Corner 1941]. , detail:

Dwarf form: Commonly seen all over the country. Vernacular: Khem chompoo เข็มชมพู (Bangkok); “Dwarf Pink Coccinea”.

[Ixora coccinea] Not formally recognized as “variety”:

A form with pure white flowers and buds. Not known from the wild. Popular and widely grown. (although not as common as the red-flowered forms). Vernacular: ??.

 Dwarf form: Appears to be more common than the “normal” form. Vernacular: ??; “Dwarf White Coccinea”.

#Ixora congesta Roxb., Fl. Ind. 1: 397. 1820.

Shrubs or small trees to 3 m tall. Leaves coriaceous, broadly elliptic to oblong, 13–21 by 5–12.5 cm, base obtuse, apex acuminate or acute, mucronate; 12–20 pairs of lateral veins; petioles 10-30 mm long; stipules 2–3 mm long, the apical awn 1 mm long. Inflorescence often with 3 main branches, many-flowered, corymb-like. Flowers not fragrant, shortly pedicellate. Calyx lobes elliptic, 2-3 mm long, acute. Corolla yellow or pinkish turning red, tube 30–50 mm long, lobes ovate-lanceolate, 8-10 mm long, blunt at apex. Fruits globose, 7–12 mm in diam.

Widely grown. Naturally occurring from lower Myanmar and West Malaysia to the Moluccas, but never found the wild in Thailand. Vernacular: Khem Deang เข็มแดง (Bangkok).

#Ixora hookeri (Oudem.) Bremek., Repert. Spec. Nov. Regni Veg. 37: 194. 1934.— Pavetta hookeri Oudem., Ned. Plantent. 2: t. 28-29. 1866.— Ixora odorata Hook., Bot. Mag. 71: t. 4191. 1845, nom. illeg. [see comment below]

Shrubs to 3 m tall. Leaves coriaceous, elliptic or ovate, 2.5–7.5 by 1–4 cm, base obtuse, apex acute, mucronate; 7–9 pairs of lateral veins; petioles 3–4 mm; stipules 3.5–5 mm long, outside hairy, the apical awn short, to 1 mm long. Inflorescence many-flowered, rather lax, ± drooping. Flowers fragrant, shortly pedicellate. Calyx lobes ovate, to c. 10 mm long, acute. Corolla white, tube 60-70 mm long, lobes oblong, 5–7 by 1–3 mm, narrowed towards base. Fruits globose, 6 – 10 mm in diam.

A quite recent introduction which appeared as an ornamental in the Bangkok area within the last few years. Vernacular: Khem Hawaii เข็มฮาวาย (Bangkok). The vernacular name is misleading: the species is endemic to Madagascar; plants may have been obtained from a Hawaiian nursery.

In horticultural literature and nurseries often under the illegal name Ixora odorata [Hooker’s name is predated by Ixora odorata (G.Forst.) Spreng., Syst. Veg. 1: 409 1824 (based on Coffea odorata G.Forst., Fl. Ins. Austr.: 16. 1786; now Psydrax odorata (G.Forst.) A.C.Sm. & S.P.Darwin, in Fl. Vitiensis Nova 4: 230 (1988)].

#Ixora macrothyrsa (Teijsm. & Binn.) T.Moore, Florist & Pomol.: 76. 1878.

Shrubs or small trees to 5 m tall. Leaves subcoriaceous, elliptic or lanceolate, 7.5–17.5 by 4–7 cm, base obtuse, apex acuminate or acute, mucronate; 2–4 pairs of main lateral veins; petioles 3-5 mm long; stipules outside hairy, 2.5–5 mm long, the apical awn short, to 1 mm long. Inflorescence rather lax and broad, to c. 15 cm in diam., many-flowered. Flowers not fragrant, pedicels to 15 mm long. Calyx lobes ovate, acute. Corolla scarlet-red, tube c. 30 mm long, lobes oblong, 5–7 by 1–3 mm, narrowed towards base, acute at apex. Fruits globose, 6 – 10 mm in diam. ,

Planted all over the country but more commonly cultivated in the Peninsula than elsewhere. A native of Sulawesi (Celebes). Vernacular. Khem Daeng เข็มแดง (Bangkok).

Some forms of I. congesta may be difficult to distinguish from the species.

#Ixora ‘Sunkist’ [nom. hort.] Corner, Gard. Bull. Str. Settl. 9: 235. 1941.

Dwarf shrubs to 1 m tall. Leaves subsessile, coriaceous, lanceolate elliptic to lanceolate obovate, 1.5–4 by 1–2.5 cm, gradually or rather suddenly narrowed to the base, apex acute or subacute; 6–13 pairs of lateral veins; stipules 2– 3 mm long, the apical awn 1 mm long. Inflorescence corymb-like, many-flowered, inflorescence axes red. Flowers not fragrant, shortly pedicellate. Calyx lobes ovate, 1-2 mm long, acute. Corolla pinkish apricot yellow turning brick red, yellow or pinkish fading flushed white, corolla tube 22-30 mm long, lobes lanceolate, 5–7 by 1–3 mm, acute or subacute. Fruits globose, green turning reddish to black, 4–6 mm in diam.

A dwarf form reminding of and difficult to distinguish from Dwarf Coccinea cultivars (see above). Planted all over Thailand, but – because of its  similarity to Dwarf Coccinea cultivars – it remains uncertain how widely it is grown.  Not known from the wild and described from material cultivated in the Peninsular Malaysia. As it combines characters of I. chinensis, I. javanica and I. coccinea, it might be of hybridogenous origin. Vernacular: Khem Yeepon เข็มญี่ปุ่น (Bangkok); Khem Phitsanulok เข็มพิษณุโลก (Bangkok).

Mussaenda L.

See page 000-000 for details on the genus. Only two exotic (but no indigenous) species are widely grown in Thailand:

#Cultivars of Mussaenda philippica A.Rich., Mém. Rubiac.: 165. 1830. In part, formally recognized as

Mussaenda philippica A.Rich. var. aurorae Sulit, Philipp. J. Forest. 2: 39. 1939.— Mussaenda philippica A.Rich. f. aurorae (Sulit) Jayaw., J. Arnold Arbor. 45: 131. 1964. [See explanation below]

Shrubs or small trees to c. 4 m tall, not scandent. Inflorescences much-branched, many-flowered. Flowers 5-merous. Calyx lobes of all flowers of all inflorescences enlarged, leaf-like, white or various shades of pink (“show calyx leaves”); no small, “normal” calyx lobes present. Corolla yellow, with an orange “eye” in the centre (i.e. a ring of orange hairs surrounding the corolla throat). Fruits usually not developed.

The grown cultivars differ quite strikingly from the “typical” form of this species (which looks very much like a “normal” Mussaenda and only has few calyx lobes per inflorescence expanded into white “show calyx leaves”). They can only be propagated vegetatively because this aberrant increase in enlarged, petaloid calyx leaves came about by a natural mutation which had occurred in some plants of M. philippica in Luzon Province (Philippines) [formally recognized as var. or f. aurora]. These plants were eventually taken in cultivation and became known as M. philippica cultivar “Doña Aurora”, named after the wife of a former Philippine President.

The “Doña Aurora” cultivars have, like the “normal” M. philippica, white enlarged calyx leaves [-fig.B]. In addition, there are cultivars with enlarged calyx leaves in various shades of pink (collectively known as “Pink Doñas”) [-fig. A,B-E]. All of these originated basically by crossing the “Doña Aurora” cultivar (white show calyx leaves) with M. erythrophylla (bright red show calyx leaves; see below). Various shades of pink were achieved by backcrossing of F1 hybrids with other cultivars. In Thailand, one of these crosses is known as cultivar “Queen Sirikit”; it, however, is not easily separable from other pink Philippica cultivars such as “Doña Luz” (which is widely grown many parts of Southeast Asia and is a much older cultivar than “Queen Sirikit”).

 Philippica cultivars, both pink and white,  are very widely grown ornamentals in Thailand; frequently, white and pink cultivars are planted side by side. They appear to require a climate with continuously high humidity and are, therefore, most commonly seen in the Peninsula and the wet Southeast. They are, however, also cultivated in many other parts of the country, as far North as Chiang Mai Province, where one can see them primarily in the low-lying areas.

#Mussaenda erythrophylla Schumach. & Thonn. in C.F.Schumacher, Beskr. Guin. Pl.: 116. 1827.

Scandent or climbing shrubs (but cultivated plants mostly trimmed into “formal” shrubs and, therefore, not showing the characteristic scandent or climbing habit). Inflorescences several-flowered, inflorescence axes densely covered with long, red hairs. Flowers 5-merous. Calyx lobes small, narrowly lanceolate, densely red-hairy, but typically 2 or 4 flowers per inflorescence with a solitary, enlarged, bright (carmine-)red flag-like calyx leaf (“show calyx leaf”). Corolla tube densely red-hairy on the outside, lobes white to creamy-white; corolla with a dark-red “eye” in the centre (i.e. a ring of dark-red hairs surrounding the corolla throat). Ovary densely red-hairy. Fruits usually not developed in cultivated plants.

 This West tropical African species is not as widely planted as the M. philippica cultivars; it is more often seen in the peninsula than elsewhere in Thailand.

Plants with pink or white show calyx leaves, in horticultural literature sometimes referred to as M. erythrophylla cultivar “Rosea” or cultivar “White,” belong to the M. philippica cultivar complex (see above).

#Pentas Benth.

A genus of about 40 species, occurring naturally in Africa, Madagascar and SW Arabia; several species with attractive flowers are grown as ornamentals; only 1 of them cultivated in Thailand:

#Pentas lanceolata (Forssk.) Deflers, Voy. Yemen: 142. 1889.

Erect perennial herbs, sometimes a little woody at base, to ca. 0.5 m tall, or low and cushion-like in some cultivars. Leaves decussate, membra­nous, petiolate to subsessile; stipules divided into several filiform segments. Inflorescence terminal, consisting of many-flowered cymes in corymb- to umbel-like arrangement. Flowers 5-merous, mostly heterostylous. Calyx with unequal lanceolate lobes. Corolla white to pinkish, lilac, mauve or magenta, sometimes two-toned (dark pink with white stripes, etc.) in cultivars, infundibular, tube narrowly cylindrical, lobes valvate in bud, spreading in open flowers. Stamens completely included in slightly dilated upper part of tube (long-styled morph) or anthers on long filaments exserted (short-styled morph). Ovary 2-celled, each locule with numerous ovules on a large placenta attached to the septum; style with 2-lobed stigma included in short-styled and exserted in long-styled morph. Fruits capsular, splitting into 2 valves, with numerous, minute seeds.

Presumably a fairly recently introduced ornamental which appears to become increasingly popular in Thailand. Various cultivars are grown: (a) rather robust, erect, subshrubby plants (closely resembling the habit of plants growing in their natural environment) which are primarily cultivated in pots; (b) erect dwarf-forms not more than ca. 10 cm tall and (c) low, cushion-like forms. (b) and (c) make attractive flower beds and flowering borders.

#Pseudomussaenda Wernh.

An African genus of about 5 species; 1 widely cultivated in Thailand:

#Pseudomussaenda flava Verdc., Kew Bull. 6: 378. 1951 (publ. 1952).— Mussaenda flava (Verdc.) Bakh.f. in C.A.Backer, Bekn. Fl. Java 15(173): 72. 1956.

Shrubs to c. 3 m tall. Leaves decussate, shortly petiolate; stipules apically with 2 filiform lobes. Inflorescence terminal, consisting of several-flowered cymes. Flowers 5-merous, heterostylous. Calyx lobes of most flowers small and filiform, but 1–2 flowers per inflorescence with a single, enlarged foliaceous white to creamy-yellow calyx lobe. Corolla yellow, infundibular, the cylindrical tube swollen where the subsessile anthers are located, the throat often with a ring of lemon- to orange-yellow hairs. Stamens inserted in the upper half of the tube, below the throat in short-styled morphs. Ovary 2-celled, each locule with numerous ovules on a large peltate placenta attached to the septum; style with 2-lobed stigma included in both long- and short-styled morphs but relatively longer in long-styled morphs. Fruits capsular, with numerous small seeds.

Cultivated primarily in peninsular Thailand; not a common ornamental.

Similar to Mussaenda (and in horticultural literature often called Mussaenda flava) but generically distinct (confirmed by molecular data!) and distinguished by having dry, capsular fruits loculicidally splitting into two valves [vs. indehiscent, berry-like fruits in Mussaenda).

Psilanthus Hook.f.

See page 000-000 for details on the genus and on

Psilanthus bengalensis (Roxb. ex Schult.) J.-F.Leroy

A shrub quite widely cultivated for its fragrant flowers; often seen around temples.

#Rondeletia L.

A large neotropical genus of c. 90 species; 1 Cuban species sometimes cultivated in Thailand:

#Rondeletia odorata Jacq., Enum. Pl. Carib.: 16. 1760.

Shrubs c. 1–2 m tall. Leaves decussate, thick-leathery, blades bullate, obtuse to subcordate at base, rounded or acute at apex, petiole subobsolete; stipules triangular. Inflo­rescence terminal, consisting of pedunculate cymes united into a semi-globose several- to many-flowered thyrse. Flowers 5-merous, hermaphrodite. Calyx with narrowly oblong lobes. Corolla bright red or orange-red, the center with distinct a yellow(-orange) “eye”, tube cylin­drical, lobes rounded, imbricate in bud and spreading in open flowers. Stamens inserted in upper third of tube, the subsessile anthers included. Ovary 2-celled, each locule with numerous ovules on a large placenta attached to the septum; style with 2-lobed stigma barely exserted from throat. Fruits small, globose, capsular, splitting into 2 valves; seeds numer­ous, minute.

Confirmed sightings from some towns in Peninsular Thailand and from Bangkok. Not widely planted.

#Serissa Comm. ex Juss.

A monotypic genus occurring naturally probably in S. China and Taiwan only. Quite widely cultivated in Thailand:

#Serissa japonica (Thunb.) Thunb., Nov. Gen. Pl.: 132. 1798.— Lycium japonicum Thunb., Nova Acta Regiae Soc. Sci. Upsal. 3: 207. 1780.— Lycium foetidum L.f., Suppl. Pl.: 150. 1782.— Serissa foetida (L.f.) Lam., Tabl. Encycl. 2: 211. 1819.— Democritea serissoides DC., Prodr. 4: 540. 1830. — Serissa serissoides (DC.) Druce, Bot. Soc. Exch. Club Brit. Isles 4: 646. 1917.— Leptodermis venosa Craib, Bull. Misc. Inform. Kew 1916: 264. 1916; Pitard in Fl. Gén. I.-C. 3(3): 408. 1922.

Shrubs or dwarf shrubs to c. 0.5 m tall; all vegetative parts foetid when bruised. Leaves decussate, subcoriaceous, shortly petiolate, variegated in some cultivars; stipules connate below, triangular. Inflores­cences terminal on abbreviated short shoots (and, thus, often seemingly axillary), uniflorous or consisting of a cluster of few flowers. Flowers 4–6-merous, hermaphrodite, heterostylous. Calyx with small triangular lobes. Corolla white to pale pink, infundibular, tube hairy inside, lobes valvate-induplicate in bud, spreading to recurved in open flowers. Stamens inserted around or below the throat, anthers exserted in short-styled and included in long-styled morphs. Ovary 2-celled, each locule with a solitary, basally attached locule; style with 2-lobed stigma long-exserted in long-styled or included short-styled morph. Fruits small, capsular, opening by means of an operculum, releasing 2 one-seeded pyrenes.

Many, rather diverse looking cultivars are cultivated. The most common are low, dwarf shrubby forms used as small hedges or flower bed borders. Quite often cultivars with variegated leaves (yellowish-white leaf edge; cv. “Variegata”) are grown [- fig.C-D]. The plant is, despite its unpleasant foetid odour (identical to that of Paederia and several other Thai Rubiaceae; see p. 000, 000), popular as bonsai (smaller in all aspects except for the flowers) [- fig.B]. Double-flowered cultivars, frequently cultivated in other parts of SE. Asia, are rather uncommon in Thailand.

In horticultural literature often known under the incorrect name Serissa foetida; S. serissoides is now often considered a synonym, although this is not generally accepted.

#Spermadictyon Roxb. (syn. Hamiltonia Roxb.)

A monotypic genus occurring naturally from Pakistan to S. China; rarely cultivated in Thailand:

#Spermadictyon suaveolens Roxb., Pl. Coromandel 3: 32. 1815.— Hamiltonia suaveolens (Roxb.) Roxb., Fl. Ind. ed. 1, 2: 223. 1824.

Shrubs to c. 1.5 m tall; all vegetative parts foetid when bruised. Leaves decussate, subcoriaceous, petiolate; stipules triangular, persistent. Inflorescence terminal, many-flowered, panicle- to ± umbel-like. Flowers fragrant, 5-merous, hermaphrodite, ? heterostylous. Calyx with small, subulate lobes. Corolla white to pale blueish or pinkish, infundibular, with a relatively long tube and short, oblong lobes, the latter valvate in bud. Stamens inserted at the throat, anthers subsessile. Ovary 5-celled (at least when young), each locule with a solitary, basally attached locule; style with 5-lobed stigma exserted. Fruit capsular, crowned by persistent calyx, the exocarp splitting into 5 valves from the apex downward. Seeds 5 (or fewer by abortion), loosely enclosed by the net-like interconnected vascular bundles of the endocarp.

Grown for its showy, fragrant flowers. Only once observed in a garden in Chiang Mai and not noticed in recent years. Possibly no longer in cultivation.

Undoubtedly close to Leptodermis (see p. 000) with which it shares the peculiar net-like structure which surround the seeds [“Spermadictyon” means “seed net”].

 

2. Plants of major or minor commercial value

The only genus of significant importance is Coffea (coffee) which has become one of Thailand’s major cash crops; the 3 commercially important species are described below. All other taxa listed here are only grown very locally and, in general, are of little economic importance.

#Cinchona L.

A genus of 23 species confined to NW. South America; 1 species, naturally occurring from C. Peru to C. Bolivia, occasionally grown in Thailand:

#Cinchona calisaya Wedd., Ann. Sci. Nat., Bot., III, 10: 6. 1848.— Cinchona ledgeriana (Howard) Bern.Moens ex Trimen, J. Bot. 19: 323. 1881.

Trees to ca. 5 m tall. Leaves decussate, subcoriaceous, petiolate; stipules broadly triangular, caducous. Inflorescence terminal, panicle-like, many-flowered. Flowers 5-merous, hermaphrodite, heterostylous. Calyx with small triangular lobes. Corolla white to pinkish-white, hypocrateriform, tube hairy inside, lobes valvate in bud, reflexed in open flowers, lobe margins densely beset with long, white hairs. Stamens included in long-styled or tips of anthers exserted in short-styled morph. Ovary 2-celled, each locule with numerous ovules on a peltate placenta attached to the septum; style with 2-lobed stigma included in short-styled or just the tips of the sitgmas exserted in long-styled morph. Fruits capsular, crowned by persistent calyx, elongate-ellipsoid, thinly woody, septicidally splitting from the base upwards. Seeds numerous, laterally flattened, with strongly dentate to ± fimbriate bipolar wings.

 The species (better known under its old name C. ledgeriana) has probably never been planted on a larger scale in Thailand; it is known from a few localities in the North (e.g. in the Medicinal Garden of the Forestry Experimental Station on Doi Suthep, or in Doi Inthanon National Park). Strains of this species have, in the past, been of commercial importance as a source for quinine, an alkaloid chemical in the bark which has a high antimalarial effect and which is, because of its bitter­ness, used in commercially produced tonic water. After the successful development of synthetic quinine in the mid 1940’s the importance of Cinchona as a commercial crop plant dropped dramatically; most malaria drugs now contain the less expensive syn­thesized quinine.

 

#Coffea L.

Shrubs or small trees with decussately arranged, ascending to ± horizontal lateral branches. Leaves opposite, evergreen, glossy above, petiolate; stipules small to large, triangular to rounded, acute or obtuse at apex. Inflores­cences paired, axillary, consisting of few- to many-flowered congested cymes. Flowers fragrant, 4–9-merous, hermaphrodite. Calyx ring-like, minute, often with small indistinct teeth. Corolla white, tube shorter than lobes, lobes contorted in bud, spreading in open flowers. Stamens inserted at the throat, fila­ments ± as long as the linear anthers, exserted. Ovary 2-celled, each locule with a solitary ovule on a placenta at­tached to the middle of the septum; style with 2-lobed stigma (slightly) exserted. Fruit drupaceous, ellipsoidal to globose, usually red, with 2 one-seeded, thin-walled pyrenes; seeds plano-convex, with a slightly curved fold on the flat ven­tral side. [description applicable to cultivated species only].

A genus of c. 90 species native to tropical Africa, Madagascar and the Mas­carenes [all indigenous Thai species previously associated with Coffea have since been removed to other genera]; 3 grown in Thailand, the first 2 of major economic importance:  

#Coffea arabica L., Sp. Pl.: 172. 1753; Craib in Fl. Siam. En. 2(2): 171. 1934.

Treelet or bush to c. 5 m tall (usually kept shorter in plantations). Leaves (broadly) elliptic or oblong-elliptic, to 15(18) cm long, with 7-10 pairs of lateral veins, distinctly acuminate at apex, margins undulate in some cultivars; stipules triangular, acute, 4-8 mm long. Flowers mostly 5-merous, in axillary clusters of 2-20. Fruits oblong-ellipsoid to subglobose, 10-20 by 10-12 mm. , - fig. C-D

This is “Arabica Coffee,” a “highland” coffee, normally cultivated from c. 800 m upwards (although it can sometimes be seen at low altitudes also, but then only as one or few plants grown in gardens and not as commercial large-scale plantations). Often seen in Thailand’s northern provinces where it is frequently cultivated by hill tribe families and villages; in recent years, however, also larger-scale plantations have been started.

Economically less important than “Robusta Coffee” (below). Several hundred tons of Arabica Coffee are produced per year; almost entirely processed and consumed locally.

#Coffea canephora Pierre ex A.Froehner, Notizbl. Bot. Gart. Berlin-Dahlem 1: 237. 1897.— Coffea robusta L.Linden, Cat. Pl. Econ.: 64. 1900.

Treelet or bush to c. 8 m tall (usually kept shorter in plantations). Leaves oblong-elliptic, broadly elliptic or occasionally obovate to lanceolate, to 35(40) cm long, with (8)11-15(17) pairs of lateral veins, distinctly acuminate at apex, margins often somewhat undulate; stipules deltoid, acute at apex or at least with an apical mucro, 6-18 mm long. Flowers 5-6(7)-merous, in axillary clusters of 8-30(50). Fruits broadly oblong-ellipsoid, 10-15 by 5-12 mm. - fig. A-C

This is “Robusta Coffee,” a “lowland” coffee, normally cultivated from sea level to an altitude of a few 100 m. Grown in large plantations primarily in the Peninsula, from Chumphon Province southwards. It is easier to cultivate, more disease-resistant, can tolerate higher temperature and greater moisture extremes, produces more beans, and the fruits mature considera­bly more quickly than Arabica.

More than half of the c. 80.000 tons of Robusta Coffee produced annually are exported, whereas the rest is used and processed locally (canned coffee drinks; instant coffee). Thailand now ranks third (behind Vietnam and Indonesia) amongst the Southeast Asiatic Robusta Coffee producers.

#Coffea liberica Hiern, Trans. Linn. Soc. London, Bot. 1: 171. 1876; Craib in Fl. Siam. En. 2(2): 172. 1934.

Tree to 20 m (if allowed to grown) or bush to c. 8 m tall. Leaves (narrowly) obovate or elliptic, to c. 35 cm long, with (7)8-13 pairs of lateral veins, often rounded or obtuse, or rounded with a short acumen at the apex, margins slightly undulate; stipules triangular-ovate, obtuse at apex, small, 2-4 mm long. Flowers 5(-9)-merous, in axillary clusters of 4-30(50). Fruits broadly oblong or oblong -ellipsoid, 12-22 by 10-15 mm.

This is “Liberica Coffee”, also a “lowland” coffee, which is scatteredly cultivated in the Peninsula and in the Southeast. It is generally not grown in large-scale plantations.  As compared to Robust and Arabica Coffee, its economic importance is minor.

 

Mitragyna Korth.

Mitragyna speciosa (Korth.) Havil.

See page 000-000 for details on the genus and on the above indigenous species which grown in the Peninsula for use as  a (semi-) legal drug. Vernacular: “Kratom”.

#Vangueria Juss.

A genus of c. 15 species occurring naturally in Africa and Madagascar; 1 widespread Afro-Madagascan species occasionally cultivated in Thailand for its fruits:

#Vangueria madagascariensis J.F.Gmel., Syst. Nat.: 367. 1791; Craib in Fl. Siam. En. 2(1): 145. 1932.— Vavanga chinensis Rohr, Skr. Naturhist.-Selsk. [Acta Soc. Hist. Nat. Hasn.] 2(1): 207. 1792.— Vavanga edulis Vahl, Skr. Naturhist.-Selsk. [Acta Soc. Hist. Nat. Hasn.] 2(1): 208 & t. 7. 1792.— Vangueria edulis Vahl, Symb. Bot. 3: 36. 1794.

Shrub or several-stemmed small tree to c. 5 m tall. Leaves opposite, membranous, petiolate; stipules broadly triangular at base, narrowly lanceolate to linear above, villous inside. Inflorescences axillary, paired, pedunculate, consisting of lax dichasial cymes. Flowers 5-merous, hermaphrodite, small. Calyx lobes narrowly triangular, spreading or recur­ved. Corolla greenish-yellow, yellowish or cre­amy-white, tube wide, broadly funnel-shaped, inside with a ring of deflexed hairs, lobes mostly shorter than tube, acute. Stamens inserted at the throat, filaments short, anthers partly exserted. Ovary 5-locular, 1 ovule per locule pendu­lous from placenta attached to near top of septum; style with a ± cylindrical stigmatic knob, slightly exserted. Fruits drupaceous, large (c. 30 mm in diam.) and globose, with 5 (or occasio­nally fewer by abortion) pyrenes; pyrenes woody; mostly only one fruit per inflorescence.

A fruit tree of minor importance, not very frequently seen in Thai gardens. Known as “Spanish tamarind” because the taste of its fruits is faintly resembling those of tamarinds. In literature on tropical fruits trees often incorrectly called Vangueria edulis.

 



[1] C. Puff