For several decades, my research has primarily centred on Rubiaceae, and especially those occurring in the Old World tropics. Most of the research articles (see publications) were based on a broad, multidisciplinary approach, covering growth form and habit, habitats, pollination ecology, fruit structure and diaspore dispersal, gynoecial structure, palynology, karyology, phytochemistry, etc. (this was before the "DNA area"). - See below for details on current Rubiaceae [tab "RUBIACEAE"] and non-Rubiaceae projects ["OTHER"].
Most of the publications would not have been possible without the material obtained during field work. Apart from many trips in Central and Eastern Europe, in the Mediterranean region and in North America, numerous collecting expeditions to tropical and subtropical countries (mostly, but not exclusively, in the Old World) were carried out. See below for details. I still go on botanical expeditions every year (on average, about 3 months per year). - For details click the tab "EXPEDITIONS" below.
A large collection of preserved Rubiaceae material, including DNA samples, is available (obtained mostly during field work in the regions listed above).
In addition, there is a huge collection of (mostly) botanical illustrations consisting of over 40.000 pictures (of which close to 35.000 are color slides; the remaining digital images). See a selection of pictures HERE. [Press F11 to view in full screen mode (recommended!)]

Current RUBIACEAE projects

Rubiaceae for Flora of Thailand
The family, with over 100 genera and about 600 species in Thailand, is to be published in at least 2 parts. The first part is expected to be published in 2010.

Genera and species that have been completed are available online. Enter the Flora of Thailand Rubiaceae subsite HERE.

Paederia ntiti sp. nov. (Rubiaceae) from the Comoros: notes on the affinities of Comorian rubiaceous climbers and lianas
[Arnaud Mouly and Christian Puff ; Nordic J. Bot., accepted for publication (to be published 2010)] - publ. June 20, 2010 - see Publications]

Mycetia basiflora (Rubiaceae), a new species endemic to SE Thailand
[in cooperation with Bob Harwood; expected to be published 2010 in Thai Foret Bullein (Botany) - publ. Dec 2010: PDF ]
A recently discovered new Myectia species easily distinguished from all other taxa of the genus by having basiflorous inflorescences; only known from three geographcially well separated populations in the Khao Soi Dao, he highest mountain massif in SE Thailand.

[photographs: Bob Harwood (2), Christian Puff (1)]
Take mouse over image for enlarged view!

Secondary pollen presentation in Coptosapelta (Rubiaceae)
[under preparation]
In contrast to many other Rubiaceae with secondary pollen presentation (SPP) [see survey by Puff et al., 1996), pollen is deposited directly on the stigma of the same flower ( the stigma itself thus functions as pollen presenter). Using anatomical data and supporting SEM images, the article demostrates how Coptosapelta prevents self-pollination and -fertilization.

Rubiaceae of Borneo. A pictorial guide to the genera occurring in the island
[in cooperation with Prof. Khoon Meng Wong; under preparation]
In design and layout similar to the published book Rubiaceae of Thailand. A pictorial guide to indigenous and cultivated genera.

Tenative cover. Take mouse over image for enlarged view!

Current non-Rubiaceae projects

Living under water for up to four months of the year:
Observations on the rheophytes of the Mekong River (Thailand/Laos border)

[ready for publication] - publ. Dec.2011 [PDF]
The Mekong, the longest river in Southeast Asia originating in the Tibetan Plateau and entering the South China Sea in Vietnam, shows a strong fluctuation of water level. The summer snowmelt in eastern Tibet and the rains in the river's upper reaches cause the water level to rise dramatically.
In the study area [a roughly 100 km long stretch of river from the area of the Mekong – Mun (Moon) confluence  upstream (northward); Thailand/Laos border], the water level of the river varies by several (locally probably up to 10) meters during dry season (November-April) and rainy period (May-October).

ABOVE: A. Mekong in the dry season (note "rock islands") and B. in the dry season. BELOW: Study area and habitats in the dry season (in the satellite image, rocky areas show up in white color). - Take mouse over images to enlarge!

Plant life (predominantly trees and shrubs) in at and the immediate edge of the Mekong is existing under very extreme conditions: During periods of the highest water levels they are entirely submerged and “invisible” (in the study area they are typically living underwater up to 4 months, i.e., from July to October). Only when the water level goes down, the wealth of the plants becomes apparent, and in the dry season they are often living in seemingly bone-dry habitats such cracks of rock or sandbars or sandy shores (see illustrations below).  As defined by van Steenis (1981, 1987) these plants are rheophytes. They are, however, rather “extreme” kinds of rheophytes, being under much more strain that “normal” or “typical” ones elsewhere. “Typical” rheophytes, common throughout the tropics, will hardly ever be submerged for such a long period of time (short or long heavy tropical rainstorms in the upper reaches of a stream may because the water level to rise for several hours to a few days, or – during a longer rainy spell – for a few weeks, but hardly for several months).
Examples of a few "extreme" Mekong rheophytes:

Clockwise from upper left: sandy shore (much less common than rocky areas!) with large clumps of Combretum trifoliatum); Anogeissus rivularis (Combretaceae); Acacia harmandiana; one of the 2 "trunkless" Syzygium spp. (Myrtaceae), crowns adpressed to rocks. - Take mouse over images to enlarge!

Overview of expeditions from the 1970s onward

Paleotropics - AFRICA and MADAGASCAR:
• southern Africa (South Africa, incl. Transkei, Bophuthatswana and Venda; Lesotho; Swaziland; Botswana; Namibia): 1976, 1978, 1979, 1980, 1984. • Zimbabwe: 1979. • Mozambique: 1984. • Malawi: 1978*, 1979 (*with excursions to Zambia). • tropical East Africa (Kenya, Tanzania, Uganda): 1977/78, 1982, 1983, 1986. • West Africa (Sierra Leone, Guinea): 1981, 1990. • Ethiopia: 1981, 1982, 1982/83, 1983, 1986, 1987, 1988, 1996, 1998, 1999, 2000, 2001, 2003, 2006, 2011, 2013. • Egypt: 1982. • Madagascar: 1980, 1985. • Mauritius: 1980.
Paleotropics - ASIA:
• Sri Lanka: 1991. • India - Assam, Nagaland: 2013. • Thailand: 1986, 1987/88, 1988, 1989, 1990, 1992, 1993, 1995, 1996, 1997 (x2), 1998, 1999, 2000, 2001, 2002 (x2), 2003, 2004 (x3), 2006 (x2), 2007 (x3), 2008(x2), 2009 (x2), 2010 (x2), 2011. • Singapore (with excursions to Malaysia): 1988. • Malaysia (West Malaysia): 1995, 1998, 2000, 2001, 2002 (x2), 2003 (x2), 2004, 2005, 2006 (x2), 2009, 2010. • Borneo - Brunei: 1989, 1990, 1992, 1999, 2000; Borneo - Sabah: 1989, 1992, 1993, 1995, 1996, 2000, 2001, 2005; Borneo - Sarawak: 1996, 2000. • Philippines: 1989. • Indonesia: 1992, 2003 (Bali, Java). • Southwest-China: 1988. • Vietnam: 1996, 1999, 2000, 2004, 2005. • Cambodia: 2008. • Subtropical and tropical Japan: 1986/87 (Kyushu), 1988 (Shikoku, Ryukyus: Okinawa), 1993 (Kyushu, Amami Isl.).• Australia (Queensland): 2001.
• Mexico and Guatemala: 1972/73. • Cuba: 1990. • Colombia: 1992. • Brazil: 2001.

For an overview of upcoming expeditions see here [click tab "CALENDAR"].

To see to some pictures from selected expeditions click HERE. - Press F11 to view in full screen mode (recommended!)

Expedition crew in front of Parashorea tomentella (DIPTEROCARPACEAE) [Borneo Sabah]