<p><strong>The phylogenetic position and taxonomic status of the Southeast and South Asian bamboo genera <em>Neohouzeaua</em> and <em>Ochlandra</em> (Poaceae: Bambusoideae) </strong></p>

Abstract

Among the tropical woody bamboos, the Melocanninae is one of the most clearly recognized subtribes morphologically and has also been consistently well delimited in molecular phylogenetic work. The relationships among those genera in this subtribe, however, have been contentious because of poorly understood generic delimitations, in part due to poor specimen material or insufficiently assessed morphological traits, sometimes exacerbated by poorly accessible provenances. We address the phylogenetic and taxonomic status of two groups which together include the largest number of species in this subtribe: the Neohouzeaua-Schizostachyum complex, distributed from India to South China, Southeast Asia and southwest Pacific, and the endemic Indian genus Ochlandra. Three Neohouzeaua species (including the generic type), 12 Schizostachyum species (including the generic type and several species of uncertain placement), together with five species of Ochlandra and representatives of Cephalostachyum, Melocanna and Pseudostachyum were assessed in a molecular phylogenetic analysis together with members of other well-distinguished subtribes. Members of Neohouzeaua and Schizostachyum align into two main groups that were not completely well-supported statistically but which members possess mostly reflexed culm leaf blades, or mostly erect culm leaf blades. Other characters which provide obvious differences between taxa, such as the number of flowers in a pseudospikelet, fusion of filaments into a staminal tube, and presence of lodicules, were inconsistent between these groups. Neohouzeaua and Schizostachyum cannot be clearly distinguished in either morphological or molecular terms, and thus are united under the latter name, which takes precedence. In reviewing names in Neohouzeaua and their basionyms, several lectotypifications are designated. Three new combinations in Schizostachyum are proposed. On the other hand, Ochlandra forms a distinct clade and its monophyly is demonstrated, supported by clear morphological characters.

The ghosts of collections past: characterisation of Neohouzeaua mekongensis (Poaceae: Bambusoideae: Bambuseae: Melocanninae) with an epitype

“…In order to understand and trace the main characters of Neohouzeaua and its related genera in the subtribe Melocanninae Benth., many publications were studied (such as Holttum, 1946;1956;Xia, 1993;Wong, 1995a;Dransfield et al, 2003;Yang et al, 2008;Sungkaew et al, 2009;BPG, 2012;Goh et al, 2013;Chokthaweepanich, 2014;Kellogg, 2015;Wong et al, 2016). With this background to the general morphology of the Melocanninae subtribe that could help in field identification and the foregoing insights into the importance of recollecting N. mekongensis from its type provenance, we organized a survey along the Mekong River from Mueang Ubon Ratchathani to Khemmarat, in the Ubon Ratchathani Province ('Ubon') in eastern Thailand.…”

“…When Holttum (1958) summarized his knowledge of the bamboos of the Malay Peninsula, he already had a broad overview of the diversity of Southeast Asian bamboos and their potential classification, based on characters of flowering material, such as the nature of the synflorescence (relatively compact and typically arising first at the apex of a leafy branch, or developing into a muchbranched structure), the basic unit of the inflorescence (whether spikelets are unable to proliferate further similar units at their base, or pseudospikelets that have basal gemmiferous bracts and are able to proliferate branch-units to form a cluster of similar units) and the nature of the style (solid and flexible, or essentially with an ovary apex that is attenuate and rigid yet hollow and containing a central strand that could represent the true style) (Holttum, 1946(Holttum, , 1956).…”

“…

Neohouzeaua A.Camus, a little-understood bamboo genus, recently treated as a synonym of Schizostachyum Nees by Goh et al (2020), was originally described with two species, N. mekongensis A.Camus and N. dullooa (Gamble) A.Camus, both of which were partially illustrated together in the same plate. The genus was taken to be typified by N. mekongensis by McClure (1957), as he considered this species was treated first by her and therefore taken as her standard of comparison.

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Thyrsostachys (Poaceae: Bambusoideae) in Thailand: taxonomy, lectotypification and natural distribution

“…Dransfield, 2000a, b;Sungkaew et al, 2007;Rattamanee et al, 2011). Perhaps because of the scarcity of flowering material, the taxonomy of bamboos will require continued study for many years to come (Clayton, 1990;Stapleton, 1993;Goh et al, 2020). Gathering information in the field to accompany a good voucher specimen is usually time-consuming (Teerawatananon et al, 2014;Sungkaew et al, 2018;Goh et al, 2020).…”

“…Perhaps because of the scarcity of flowering material, the taxonomy of bamboos will require continued study for many years to come (Clayton, 1990;Stapleton, 1993;Goh et al, 2020). Gathering information in the field to accompany a good voucher specimen is usually time-consuming (Teerawatananon et al, 2014;Sungkaew et al, 2018;Goh et al, 2020). In addition, one of the most important problems is that many collectors avoid collecting bamboos because of their size or the difficulties in trying to make good scientific specimens.…”