Mnesithea thailandica Traiperm & Boonkerd

Traiperm, P., Boonkerd, T., Chantaranothai, P. et al. (2010). Mnesithea thailandica a new species of Poaceae from Thailand. Kew Bulletin 65: 341. https://doi.org/10.1007/s12225-010-9197-0

Type

Thailand, NE31, Roi Et: Suwanaphoom Distr., Nayai, Ban Hang Hoey village, 10 June 1982, Y. Paisooksantivathana & S. Sutheesorn y1048-82 (holotypus BK).

Morphology General Habit

Perennial grass, caespitose

Morphology Culms

Culms small, erect, slender, c. 26 cm tall, internodes pilose to pubescent, nodes with densely ciliate hairs

Morphology Leaves Ligules

Ligule membranous with ciliate margins, c. 0.5 mm long

Morphology Leaves

Blades 5 – 20 by 0.4 – 0.8 mm, pubescent on both surfaces, apex acute Leaf sheaths loose, 2.5 – 6 cm long, pubescent

Morphology Reproductive morphology Inflorescences

Inflorescences racemose a compound, leafy panicle of spatheate racemes Racemes solitary, subterete, c. 6 cm long, terminal-Rhachis internodes clavate, 2 – 2.5 mm long, pubescent, rhachis nodes pubescent; spikelets in pairs

Morphology Reproductive morphology Inflorescences Spikelets

Sessile spikelets slightly twice as long as the rhachis nodes, callus pubescent Spikelets dorsoventrally compressed Pedicelled spikelets oblong, c. 1 mm long, pubescent, reduced to 2 asymmetrical glumes, keeled along the margins

Morphology Reproductive morphology Inflorescences Bracts Glume

Lower glume triangular, c. 4 by 2 mm, indurate, smooth, margins folded, pubescent on the back, apex with 2 narrow wings Upper glume ovate or boat-shaped, c. 3 by 1.3 mm, keeled on the upper and pilose along keel; lower floret barren, with small palea

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens 3; anthers yellow, c. 1 mm long; stigmas 2, plumose

Morphology Reproductive morphology Flowers Pedicel

Pedicels oblong or ribbon-like, c. 3 by 0.6 mm, pubescent.

Distribution

Endemic to Thailand.

Ecology

Common in paddy fields; 100 m.

Conservation

Only known from the type and best recorded as DD (Data Deficient) until further fieldwork is undertaken to assess the size and extent of the population. This species was described as common in paddy fields at the time of collection. Unfortunately the plants were not re-found at the type locality during the present work, probably due to the replacement of the agricultural land by industrial devevelopment.

Phenology

Flowers in June.

Note

Although only known from the type, Mnesithea thailandica is immediately distinguished from other Mnesithea spp. by the pubescence on the lower glume, rhachis internodes, nodes and pedicels. It is similar to the Malaysian species M. geminata (Hack.) Ridl. but this has a lanceolate lower glume that is just hirsute below and is glabrous on the rhachis nodes, pedicels and rhachis internodes.