Assistant Professor Dr Wilawan Promprom and Assistant Professor Dr Wannachai Chatan, researchers from the Department of Biology, Faculty of Science, Mahasarakham University, discovered a new subspecies of Ardisia crenata (Primulaceae) from Thailand.

ABSTRACT: A new subspecies of Ardisia crenata Sims (Primulaceae), namely A. crenata Sims subspecies obtusifolia Chatan & W. Promprom, collected from Nakhon Pranom Province, Thailand, is described and illustrated. The distinguishing morphological characters between two similar subspecies are discussed. The new taxa is clearly different from the other subspecies in shape, apex, margin, texture of leaf blade, primary rachis of inflorescence and sepal characteristic.

Ardisia crenata Sims subsp. obtusifolia Chatan & W. Promprom subsp. nov.

Type: Thailand: Phu Langka National Park, Nakhon Phanom Province, 210–280 m alt., 17°57’04.8″ N; 104°09’19.8″ E, December 10th, 2012, W. Chatan 1556 (holotype: BKF!; isotype: BK!, BKF! & TAI!).

Ardisia crenata subsp. obtusifolia. A. Branch with inflorescences. B. Adaxial side of leaf. C. Abaxial side of leaf. D. Inflorescences showing many floral buds, sepal aestivation and many ripe fruits (side view). E. and F. Inflorescences with four buds, a floret during anthesis and one after anthesis (E.= side view and F.= bottom view).
Ardisia crenata subsp. obtusifolia. A. Branch with inflorescences. B. Abaxial side of leaf showing venation pattern. C. Floral bud. D. Open corolla and stamens (adaxial view). E. Corolla lobes, adaxial view (left), abaxial view (right). F. Stamens, adaxial view (right), abaxial view (left). G. Pistil. H. Young (left) and ripe (right) fruits. Drawn by Wannachai Chatan from W. Chatan 1556 (A, C-G) W. Chatan 1453 (B & H).

Distribution: Ardisia crenata Sims subsp. obtusifolia Chatan & W. Promprom is an endemic to Thailand. It is only found from type locality and only one population have so far been identified by us during field investigations in the years 2012-2015 at Phulangka National Park, Ban Pheang District, Nakhon Phanom Province.

Ecology: It mostly grows in slightly dense dry dipterocarp forests or open areas, and usually grows on summits. Sometimes it grows in grassland or oak-dipterocarp forest

Phenology: Flowering in June to November and fruiting in August to February.

Vernacular name: Takai or Takai Daeng. (ตาไก่ หรือตาไก่แดง)

Conservation status: So far, Ardisia crenata subsp. obtusifolia has only been found in the type locality. The individual number of this subspecies was about 40. It should be classified as Critically Endangered (CR, D), according to IUCN red list criteria (IUCN, 2012).

Etymology: The infraspecific epithet of this subspecies was chosen for its leaf apices that were mostly obtuse.

Additional Specimens examined: THAILAND: Nakhon Phanom Province: Phu Langka National Park, December 10th, 2011, W. Chatan 1124 (BKF); September 16th, 2012, W. Chatan 1453 (BKF).

Notes: Both vegetative and reproductive morphological characters of A. crenata were variable (Larsen and Hu, 1996). They noted that the inflorescence might be simple or compound, puberulous or glabrous. Leaf blade was up to 21 cm long and its texture might be thin-chartaceous to subcoriaceous. In addition, we found some other variation of this species such as blade shape, apex, margin and highly coriaceous texture in this study.

Chatan, W. and Promprom, W. 2017. New subspecies of Ardisia crenata (Primulaceae) from Thailand. Taiwania 62(2): 116-120.

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