An investigation of lemma micromorphology in Thai Oryzeae (Poaceae)

Abstract

Nine taxa of Oryzeae that occur naturally in Thailand were studied for their lemma micromorphology using scanning electron microscopy. Common features found in most taxa were microhairs, prickles, silica bodies, and papillae. Here, features of the lemma surface are described, classified, and discussed in terms of their taxonomic significance. In addition, a key to species based on the shape of silica bodies, type of papillae and tubercles, and the arrangement of tubercles is presented. However, lemma micromorphology alone cannot be used to distinguish three species in the Oryza sativa group, namely, O. sativa, O. rufipogon, and O. officinalis.

A taxonomic revision of the tribe Oryzeae (Poaceae) in Thailand

“…The assessment conducted in this manner for the strict endemic Leersia stipitata Bor constituted a full global assessment, but for all other, more widespread taxa, this "preliminary assessment" was subject to a further round of verification following the guidelines for the application of IUCN criteria at the regional level 12 . 8,9 . See Table 1.…”

“…In Thailand, the tribe has been treated in a checklist that enumerated eleven species (one with two varieties) in four genera (namely, Oryza L., Leersia Sw., Hygroryza Nees and Zizania L.), but this lacked a key to the species and taxonomic descriptions, leading to misidentification 8 . More recently, a key to the Thai species using lemma micromorphology was published 9 , but that study was unable to provide resolution within a species complex comprising O. officinalis Wall. ex G. Watt, O. rufipogon Griff., and O. sativa.…”