Elegant bamboo (Temochloa elegans) and liliana bamboo (Temochloa liliana) strengthen the genus

NEWS - Elegant bamboo (Temochloa elegans) and elegant bare bamboo (Temochloa elegans var. glabra) are new members and strengthen the genus that previously only had liliana bamboo (Temochloa liliana S. Dransf, 2000). The new taxa were found in limestone habitats in southwest Guangxi, China, and northeast Vietnam.

Researchers from the Chinese Academy of Sciences in Guangzhou, Guiyang Vocational and Technical College in Guiyang and Vietnam Academy of Science and Technology in Hanoi described new species and varieties that strengthen the genus Temochloa into two species with two varieties.

Neomicrocalamus Keng f. and Temochloa S. Dransf. are two genera of climbing bamboos (Poaceae, Bambusoideae, Bambuseae) that are only distributed in limestone areas that are phylogenetically sister groups. The morphology has several similar characters, such as short-necked pachymorph rhizomes, climbing stems and ambiguous inflorescence structures.

Neomicrocalamus has semelauctant ‘inflorescences’, but at the same time, the basic unit of the inflorescence is a pseudospikelet because there are basal prophylls and bracts. This description is very confusing because the semelauctant and iterauctant conditions are very contrasting.

The researchers analyzed newly collected specimens from China and Vietnam to re-examine the ‘inflorescence’ structure of Neomicrocalamus and Temochloa. The new bamboo is more similar to Temochloa and grows at very low elevations (50-250 meters), while Neomicrocalamus is only found above 1000 meters.

Phylogenetic evidence suggests that the new bamboo originated from introgressive hybridization between Temochloa liliana S. Dransf. and Neomicrocalamus prainii. The newly discovered bamboo inherited 80.7% of its genome from the genetically more closely related T. liliana.

T. elegans has short-necked pachymorph rhizomes, creeping stems, solitary and nearly circular primary branchlets, branchial appendages with numerous short branches and nearly equal to the dominant central branch, occasionally repeating and approaching the size of the stem, pseudospikelets with 2-4 fertile florets, 6 stamens with notched anther tips, 3 stigmas and a caryopsis.

The species resembles T. liliana, but differs in solid (vs. hollow) stem segments, hairy (vs. glabrous) profiles on pseudospikelets, paleae longer (vs. as long) than lemmas, and palea tips that are pointed to slightly blunt (vs. 2-lobed). The species is found in southwestern Guangxi, China, and northeastern Vietnam at elevations of 210 meters.

T. elegans is found in only two localities and is not very common there so the number of mature clumps is limited. The Vietnamese population is well protected in Nature Reserves, while the Chinese population is scattered along highways and not in any protected areas. This species should be categorized as Near Threatened (NT).

T. elegans var. glabra can be distinguished from T. elegans var. elegans by its glabrous leaf sheaths and glabrous leaf ligules. The specific epithet refers to the glabrous sheaths and ligules. This taxon is found in limestone areas in northeastern Vietnam at elevations of 140-210 meters.

To date, T. elegans var. glabra is only known from one site in Vietnam and fewer than 10 clumps have been found. Inadequate field surveys have led researchers to propose a status in the category of Data Deficient (DD).

Original research

Cai Z-Y, Zhang Y-Y, Tong Y-H, Vu TC, Xia N-H (2024) Temochloa (Poaceae, Bambusoideae), a newly-recorded bamboo genus for China and Vietnam, with new taxa and a re-interpretation of flowering structures. PhytoKeys 246: 229-236, DOI:10.3897/phytokeys.246.129035