00. SPERMACOCE[1]

L., Sp. Pl. 1: 102. 1753; Puff et al., Rubiaceae of Thailand: 192 & pl. 3.4.9. 2005.–– Borreria G.Mey., Prim. Fl. Esseq.: 79. 1818.

Annual or perennial herbs or sub-shrubs; stems usually 4-angled, prostrate to erect. Leaves decussate, occasionally crowded thus appearing whorled, petiole short, the leaves usually appearing sessile; stipules partly fused with petiole and forming a sheath, its upper margin fimbriate. Inflorescences sessile, terminal and/or axillary, several- to many-flowered capitula, subtended by 1 or more pairs of leaves. Flowers 4-merous, hermaphrodite, not heterostylous, sessile, intermixed with numerous minute bracteoles. Calyx more commonly 4-lobed, sometimes 2-lobed. Corolla most commonly white in Thailand, occasionally shades of pink or mauve, infundibular to hypocrateriform, lobes valvate in bud. Stamens most commonly exserted, sometimes included; anthers dorsifixed, introrse, opening by longitudinal slits. Ovary 2-celled, each locule with a single ovule attached to the middle of a lamella, the 2 lamellas fused together to form a septum dividing the ovary; style filiform, most commonly exserted, sometimes included; stigma capitate or 2-lobed. Nectary disc on top of ovary, surrounding the base of the style, often with a papillose surface. Fruit (for species in Thailand) a 2-valved capsule crowned by the persistent calyx lobes, dehiscing septicidally from the apex downwards, valves remaining joined basally []. Seeds reticulate, rarely rugose, with a ventral groove, raphides present around margin of groove; seed outline (dorsal or ventral view) oblong, elliptic or obovate.

A genus of ca. 275 species occurring throughout the tropics, rarely extending to temperate zones, 7 in Thailand.–– Classification: subfamily Rubioideae, tribe Spermacoceae.

Four of the Thai species (S. exilis, S. latifolia, S. remota and S. verticillata ) are introduced species from South America;   2 (S. ocymoides and S. pusilla) are almost certainly native, the last  (S. articularis) is native to Asia, but not necessarily indigenous to Thailand.

Key to the species

1. Calyx (and capsule) 2-lobed

2

1*. Calyx (and capsule) 4-lobed

3

2. Corolla less than 1 mm long; stamens and style included or at most only slightly exceeding top of corolla tube; seeds short and broad (to 1 x 0.5 mm)

2. S. exilis

2*. Corolla greater than 1.5 mm long; stamens and style exserted, often exceeding corolla lobes; seeds long and narrow (to 2 x 0.5 mm)

7. S. verticillata

3. Dorsal seed surface transversely rugose

4

3*. Dorsal seed surface reticulate or almost smooth

5

4. Leaves broadly elliptic, to 25 mm long; corolla to 1 mm long

4. S. ocymoides

4*. Leaves narrowly elliptic, to 60 mm long, corolla 1.8–2.4 mm long

6. S. remota

5. Leaves linear or narrowly elliptic, greater than 5 times longer than wide

  5. S. pusilla

5*. Leaves elliptic to broadly elliptic, less than 3 times longer than wide

6

6. Seed ventrally with a deep wide excavation, seed relatively hollow; corolla white or mauve, 3–4 mm long

3. S. latifolia

6*. Seeds ventrally shallowly grooved; corolla pale mauve to purple, 3–14 mm long

 1. S. articularis

1. Spermacoce articularis L.f., Suppl. Pl.: 119. 1782.–– Borreria articularis (L.f.) F.N.Williams, Bull. Herb. Boissier, II, 5: 956. 1905.–– See also Note 2, below.

Perennial prostrate herb. Leaves elliptic, 10–35 x 3–15 mm, hispid. Capitula terminal and axillary, few-flowered. Calyx lobes green, narrowly triangular, to 1.5 mm long. Corolla pale mauve to purple, 3–14 mm long; outside glabrous except for a few hairs near lobe apex, inside a band of dense moniliform hairs near middle of tube; tube to 12 mm long; lobes to 2 mm long. Stamens exserted, not exceeding corolla lobes; anthers to 0.7 mm long, shorter than the filaments. Style equal to or slightly exceeding corolla lobes; stigma bilobed, nectary disc bipartite. Capsule with hairs on upper half, septum usually remaining erect and undamaged as valves dehisce. Seeds dark brown to almost black, obovate or elliptic, to 2.2 x 1.2 mm. reticulate, ventrally shallowly grooved. []

T h a i l a n d.— NORTHERN: Chiang Mai; SOUTH-WESTERN: Kanchanaburi, Prachuap Khiri Khan; CENTRAL: Suphan Buri, Bangkok; SOUTH-EASTERN: Chachoengsao, Chonburi, Trat; PENINSULAR: Surat Thani, Phuket, Nakhon Si Thammarat, Satun, Songkhla, Pattani, Narathiwat.

D i s t r i b u t i o n.–– India (type); naturalized in Africa, parts of Asia and Australia. Possibly native to Thailand. 

E c o l o g y.–– Open disturbed areas, usually on sand, often at beaches. Flowers and fruits April, August to December.

V e r n a c u l a r.— ??.

N o t e s. 1.–– This taxon was regarded as being a synonym of S. hispida L. until Sivarajan and Vasudevan Nair [Taxonomic and nomenclatural notes on the Spermacoce hispida-articularis complex and S. stricta-pusilla complex (Rubiaceae). Taxon 35, 363–369.1986] suggested that S. hispida was restricted to southern India, and the more widespread species (but also occurring in India) was S. articularis, although they only examined material from India. The Thailand specimens appear to all be one species, but some characteristics match those of S. articularis, and others those of S. hispida (according to Sivarajan and Vasudevan Nair’s list of how the two species differ). Previous authors had regarded S. articularis as a synonym of S. hispida. Further worldwide studies of this complex are needed to ascertain where the Thailand material belongs.
                    2. For a complete list of synonyms, including many of S. hispida L., see Sivarajan and Vasudevan Nair (l.c.).

2. Spermacoce exilis (L.O.Williams) C.Adams ex W.C.Burger & C.M.Taylor, Fieldiana, Bot., n.s, 33: 316. 1993.–– Borreria exilis L.O.Williams, Phytologia 28(3): 227. 1974, nom. nov. for Borreria gracilis L.O.Williams, Phytologia 26(6): 487. 1973, non Borreria gracilis Miq. ex Hook.f. nor Scheele.––Spermacoce mauritiana O.Gideon, Kew Bull. 37: 547. 1983.

Annual herb, prostrate or spreading. Leaves broadly elliptic, 10–35 x 6–15 mm, glabrous or with scattered hairs on veins below. Capitula terminal and axillary, to 8 mm wide. Calyx lobes 2, narrowly triangular, to 1 mm long. Corolla white, 0.4–0.8 mm long; outside glabrous, inside a few short hairs near top of lobes; tube to 0.5 mm long; lobes to 0.3 mm long. Stamens included; anthers 0.1 mm long; filaments shorter, attached near top of corolla tube. Style included; stigma shortly bilobed, nectary disc entire. Capsule glabrous, part of septum lamellas remaining attached to valves at dehiscence. Seeds brown, obovate or elliptic, to 1 x 0.5 mm, reticulate.

T h a i l a n d.–– NORTHERN: Mae Hong Son, Chiang Mai, Chiang Rai, Tak; SOUTH-WESTERN: Kanchanaburi; CENTRAL: Saraburi, Nakhon Nayok; SOUTH-EASTERN: Chonburi, Chantaburi, Trat; PENINSULAR: Ranong, Surat Thani, Phangnga, Phuket, Nakhon Si Thammarat, Trang, Songkhla, Pattani, Narathiwat.

D i s t r i b u t i o n.–– Tropical America (type from Costa Rica); naturalized throughout the tropics.

E c o l o g y.–– Slightly wetter parts of open disturbed areas, also on margins of streams. Flowers and fruits April, June to January.

V e r n a c u l a r.— ??.

3. Spermacoce latifolia Aubl., Hist. Pl. Guiane: 55. 1775.–– Borreria latifolia (Aubl.) K.Schum. in Mart., Fl. Bras. 6(6): 61. 1888.

Annual herb, prostrate or spreading. Leaves broadly elliptic, 20–75 x 10–35 mm, hispid, conspicuous raised venation on lower surface. Capitula terminal and axillary, few-flowered. Calyx lobes green, triangular, to 1.8 mm long. Corolla white or mauve, 3–4 mm long; tube to 3 mm long, glabrous except for a band of moniliform hairs inside near middle; lobes to 1 mm long, outside glabrous or an occasional hair near apex, inside usually some scattered hairs. Stamens exserted, not exceeding corolla lobes; anthers to 0.5 mm long. Style equal to or exceeding corolla lobes; stigma with 2 short linear lobes; nectary disc bipartite. Capsule with hairs mostly restricted to upper half, part of septum lamellas remaining attached to valves at dehiscence. Seeds brown, obovate or elliptic, to 3 x 1.8 mm, reticulate, ventrally with a deep wide excavation.

T h a i l a n d.–– NORTHERN: Chiang Mai, Tak, Phitsanulok; CENTRAL: Nakhon Nayok, Bangkok; SOUTH-EASTERN: Prachinburi, Rayong, Chantaburi, Trat; PENINSULAR: Ranong, Phangnga, Songkhla, Pattani, Narathiwat.

D i s t r i b u t i o n.–– Tropical America (type from French Guiana); naturalized throughout tropics of Africa, Asia and Australia. 

E c o l o g y.–– Common in wetter parts of open disturbed areas, but also collections from open and evergreen forests. Flowers and fruits June to January.

V e r n a c u l a r.–– Kradum bai yai (กระดุมใบใหญ่)  (Peninsular).

4. Spermacoce ocymoides Burm.f., Fl. Indica 34. 1768.–– Tardavel ocymoides (Burm.f.) Hiern, Cat. Afr. Pl. 504. 1898.

Annual herb, prostrate or spreading. Leaves broadly elliptic, 7–25 x 5–15 mm, glabrous or with scattered hairs on veins below and margin. Capitula terminal and axillary, to 5 mm wide. Calyx lobes narrowly triangular, length variable on individual flowers, longest to 1 mm. Corolla white, to 1 mm long, lobes to 0.9 mm, much longer than tube; outside glabrous, inside a few short hairs near top of lobes. Stamens exserted, but much shorter than corolla lobes. Style not exceeding stamens; nectary disc entire. Capsule with scattered hairs throughout, part of septum lamellas remaining attached to valves at dehiscence. Seeds dark brown, obovate or elliptic, to 1.4 x 0.8 mm, rugose.

T h a i l a n d.–– SOUTH-WESTERN: Petchaburi; CENTRAL: Bangkok.

D i s t r i b u t i o n.–– Vietnam, Indonesia (type), Philippines.

E c o l o g y.–– ??? Habitat missing. Flowers and fruits October, November.

V e r n a c u l a r.— ??.

N o t e.–– Previously confused with S. prostrata Aubl., a tropical American species now naturalized throughout the tropics.

5. Spermacoce pusilla Wall., in W. Roxburgh, Fl. Ind. 1: 379. 1820.–– Borreria pusilla (Wall.) DC., Prodr. 4: 543. 1830.

Annual erect herb to 60 cm. Leaves linear or narrowly elliptic, 20–70 x 2–5 mm, some scabrid hairs above, glabrous below. Capitula terminal and axillary, to 12 mm wide. Calyx lobes narrowly triangular, to 1.2 mm long. Corolla white or faint pink, 1.7–2.4 mm long; tube to 1.3 mm long, glabrous except for a few very short hairs inside near middle; lobes to 1.1 mm long, glabrous or an occasional hair outside near apex. Stamens exserted, equal to or exceeding corolla lobes; anthers to 0.3 mm long. Style equal to or exceeding corolla lobes; stigma indistinctly bilobed, nectary disc bipartite. Capsule with long hairs on upper half, part of septum lamellas remaining attached to valves at dehiscence. Seeds dark brown, oblong, to 1.6 x 0.7 mm, faintly reticulate. []

T h a i l a n d.–– NORTHERN: Mae Hong Son, Chiang Mai, Lamphum, Lampang, Sukhothai, Phitsanulok, Nakhon Sawan; NORTH-EASTERN: Loei, Khon Kaen; EASTERN: Nakhon Ratchasima; SOUTH-WESTERN: Uthai Thani, Petchaburi; CENTRAL: Suphan Buri; SOUTH-EASTERN: Chonburi; PENINSULAR: Surat Thani.

D i s t r i b u t i o n.–– India, Nepal (type), China, Vietnam, Indonesia, Philippines. Naturalized in Africa. 

E c o l o g y.–– Usually in open Dipterocarp forest. Flowers and fruits August to January.

V e r n a c u l a r.— ??.

N o t e s. 1.–– On the basis of a study of Indian material, Sivarajan and Vasudevan Nair [Taxonomic and nomenclatural notes on the Spermacoce hispida-articularis complex and S. stricta-pusilla complex (Rubiaceae). Taxon 35, 363–369.1986] decided that some specimens previously known as S. pusilla differed enough to be classified as a separate species, S. ramanii. The Thailand specimens appear to all be one species, but some characteristics match those of S. pusilla, and others those of S. ramanii (according to Sivarajan and Vasudevan Nair’s list of how the two species differ). Further worldwide studies of this complex are needed to ascertain where the Thailand material belongs.
                    2. For a complete list of synonyms, including those of S. ramanii Sivar. & R.V.Nair, see Sivarajan and Vasudevan Nair (l.c.).

6. Spermacoce remota Lam., Tabl. encycl. 1: 273. 1791.–– Borreria remota (Lam.) Bacigalupo & E.L.Cabral, Darwiniana 37(3-4): 334. 1999.––Spermacoce assurgens Ruiz & Pav., Fl. Peruv. 1: 60. 1798.–– Borreria assurgens (Ruiz & Pav.) Griseb., Abh. Kφnigl. Ges. Wiss. Gφttingen 24: 156. 1879.

Perennial herb, erect or spreading, to 40 cm tall. Leaves narrowly elliptic, 15–60 x 6–16 mm, scattered scabrid hairs near margin, otherwise glabrous. Capitula terminal and axillary, to 10 mm wide. Calyx lobes green, narrowly triangular, less than 1 mm long. Corolla white, 1.8–2.4 mm long; outside glabrous except for a few hairs near lobe apex, inside scattered moniliform hairs at top of tube and lower part of lobes; tube to 1.4 mm long; lobes to 1.1 mm long. Stamens exserted, filaments almost as long as corolla lobes but curling up to leave anthers situated near base of lobes; anthers to 0.4 mm long. Style as long as corolla lobes; stigma capitate. Capsule with hairs on upper half, septum usually remaining erect and undamaged at dehiscence. Seeds yellowish brown to dark brown, elliptic, to 2 x 0.8 mm, conspicuously rugose and faintly reticulate.

T h a i l a n d.–– NORTHERN: Chiang Mai, Phayao, Lampang, Tak; NORTH-EASTERN: Udon Thani; EASTERN: Nakhon Ratchasima; SOUTH-WESTERN: Kanchanaburi; CENTRAL: Saraburi, Nakhon Nayok; SOUTH-EASTERN: Chantaburi; PENINSULAR: Chumphon, Ranong, Phangnga, Songkhla, Yala.

D i s t r i b u t i o n.–– Tropical America (type from the Dominican Republic); naturalized throughout tropics of Africa, Asia and Australia. 

E c o l o g y.–– Open disturbed areas (eg roadsides, clearings in forests). Flowers and fruits June to March.

V e r n a c u l a r.–– Ya khamen (หญ้าเขมร), ya khamen lek (หญ้าเขมรเล็ก),Kradum bai yai (กระดุมใบใหญ่) (General).

7. Spermacoce verticillata L., Sp. Pl.: 102. 1753.–– Borreria verticillata (L.) G.Mey., Prim. Fl. Esseq.: 83. 1818.

Annual erect herb to 80 cm. Leaves linear or narrowly elliptic, 20–120 x 2–9 mm, some scabrid hairs near margins, otherwise glabrous. Capitula terminal and axillary, to 15 mm wide. Calyx lobes 2, green, triangular, to 1.3 mm long. Corolla white, 1.5–2.5 mm long; tube to 1.5 mm long, glabrous except for a band of moniliform hairs inside near middle; lobes to 1 mm long, outside glabrous or an occasional hair near apex. Stamens exserted, equal to or exceeding corolla lobes; anthers to 0.5 mm long. Style equal to or slightly exceeding corolla lobes; stigma bilobed, nectary disc bipartite. Capsule with hairs mostly restricted to upper half, part of septum lamellas remaining attached to valves at dehiscence. Seeds dark brown, oblong, to 2 x 0.5 mm, reticulate.

T h a i l a n d.–– EASTERN: Nakhon Ratchasima, Si Sa Ket; PENINSULAR: Nakhon Si Thammarat.

D i s t r i b u t i o n.— Tropical America (type from Jamaica); Naturalized throughout tropics of Africa, Asia and Australia.

E c o l o g y.–– Open disturbed areas. Flowers and fruits August to December.

V e r n a c u l a r.–– Chat sam chan (ฉัฅรสามชั้น) (Petchaburi); ya khi kratai (หญ้าขี้กระฅ่าย) (Prachinburi).

N o t e.–– The seeds of S. verticillata are long and narrow, the length to width ratio possibly the largest amongst the Spermacoce species worldwide, and the capsule is correspondingly long and narrow.


[1] Bob Harwood