Quercus donnaiensis
| Quercus donnaiensis | |
|---|---|
Scientific classification 
| |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Clade: | Rosids |
| Order: | Fagales |
| Family: | Fagaceae |
| Genus: | Quercus |
| Subgenus: | Quercus subg. Cerris |
| Section: | Quercus sect. Cyclobalanopsis |
| Species: | Q. donnaiensis
|
| Binomial name | |
| Quercus donnaiensis | |
Quercus donnaiensis is a critically endangered species of oak trees, endemic to central Vietnam.[2] This species belongs the Asian sub-genus of Quercus within the family Fagaceae: which have acorns with distinctive cups, characterised by growing rings of scaly protrusions; it was considered a synonym of Quercus langbianensis, but now included by Binh, Ngoc et al. (2018)[3] in the "Q. langbianensis complex".[4]
Its habitat is broadleaf evergreen montane forest, with the original description locating "Province du Haut-Donnaï; 1000-1700 m",[4] so the species name almost certainly relates to the French spelling for the upper Đồng Nai river region rather than the modern province.
Description[edit]
The original description states that the tree grows to 25 m and a distinguishing feature of Quercus donnaiensis is the yellow/golden tomentum covering the whole young tree: including young twigs, which later become glabrous and dark brown.[4]
The leaves are 100-160 x 40-50 mm, oval-lanceolate in shape, with a few peripheral teeth in upper 1/3; they are densely tomentose at first, becoming hairless, but with a persistent tomentum along midrib. this is nearly flat above, prominent beneath, with 9-14 pairs of secondary veins, at an angle of 60° from midrib; tertiary veins are not visible. The petiole is tomentose and 10-20 mm long.
Female catkins are 25 mm long, with 5-6 flowers on a tomentose rachis; there are typically 4 styles with stigmas that are thick and dark. The acorns are 15-17 mm long x 12 mm wide, loosely pubescent and rounded at tip. They are in groups of 4 to 5 on a 70-80 mm rachis and take 2 years to mature. The cupule is half-round and 15 mm in diameter, with 5-6 concentric scaley rings, enclosing 1/2 of the nut.[4]
References[edit]
- ^ Camus A. (1935) Chênes, Atlas 2: 119.
- ^ "Quercus donnaiensis A.Camus". Royal Botanic Gardens Kew. Retrieved 19 April 2024.
- ^ Binh HT, Ngoc NV, Tagane S, Toyama H, Mase K, Mitsuyuki C, Strijk JS, Suyama Y, Yahara T (2018). A taxonomic study of Quercus langbianensis complex based on morphology and DNA barcodes of classic and next generation sequences. PhytoKeys 95: 37-70.
- ^ a b c d Quercus donnaiensis in Oaks of the World archived (retrieved 19 April 2024)
