|
Plants shrub-like, densely clumping; rhizomes pachymorph, necks to 30 cm. Culms unicaespitose, to 6 m tall and 2.5 cm in diam., basally erect, apically nodding to pendulous; internodes to 30 cm, terete, usually smooth and not finely ridged, glabrous, finely purple-spotted, rarely with light to dense wax at first, becoming glossy; nodes scarcely to moderately raised. Branches 5--10 per mid-culm node at first, 7--20 later, often above promontory, subequal, initially erect, becoming deflexed, lateral branch axes lacking subtending sheaths; buds at mid-culm ovate to lanceolate, with 2 tall, single-keeled bracts, dorsally fused in lower culm, open at front (closed at culm base), several initials visible. Culm sheaths oblong, shorter than internode, deciduous; blade usually reflexed. Leaf sheaths persistent; blades small to medium-sized, usually glossy and thickened, normally not deciduous, transverse veins prominent. Synflorescence semelauctant, terminal, ebracteate or branches subtended by a series of tiny persistent delicate sheaths, without substantial internode extension on rhachis or pedicels, so highly compressed and not projecting beyond tops of vegetative leaf sheaths; branching racemose, appearing unilateral as forced to one side by vegetative leaf sheaths. Spikelets many, few-flowered; glumes 2 basally tight without subtended buds. Lemma obtuse or acute at apex and mucronate to awned. Palea equal to or shorter than lemma, 2-keeled. Lodicules 3. Stamens 3. Style 1--2. Stigmas 2--3, plumose. Caryopsis oblong. Flowering monocarpic, at very long intervals. Named after Paul Guillaume Farges (1844-1912), French missionary and naturalist in W China.
Fargesia, a temperate clumping genus endemic to C & W China, has included up to about 100 species, but most were misplaced. The genus was originally described for a species with a very dense, apparently spathed, unilateral, racemose, toothbrush-like inflorescences, and short rhizomes. It was once considered that it should be included in the earlier, Himalayan genus Thamnocalamus, which also has somewhat dense inflorescences with persistent leaf sheaths. However, bud and branch morphology as well as molecular evidence suggest that Fargesia & Thamnocalamus are not closely related.
For many years nearly all temperate clump-forming species discovered in China were described as species of Fargesia (while spreading species with pachymorph rhizomes were placed in Yushania). Several species were later found to have different branching and to lack the very dense racemose unilateral toothbrush-like inflorescences, and were moved to other genera, including Himalayacalamus, Drepanostachyum, and Thamnocalamus. A substantial number also lack the toothbrush-like inflorescences, but have the same branching and buds. They are treated here as species of Borinda or Tongpeia. It is not always easy to separate Fargesia from Borinda or Tongpeia without seeing flowers, or other important but often unrecorded features of the living plants. Most Borinda species have finely ridged rather than smooth culms, and either longer or much tougher culm sheaths. Because it was not known which of the many species in Yunnan were really Fargesia and which were Borinda, the two genera were temporarily treated as one polyphyletic genus, under the name Fargesia, to avoid the better-known species of Borinda being separated from less well known species that remained in Fargesia, e.g. in the Flora of China account. Molecular evidence has now revealed the real identity of many of these, even without flowers, see Borinda page, supporting the revised classification for this website, which recognises a smaller Fargesia and a separate Borinda.
The tightly compressed unilateral inflorescences are unique to this small genus, and represent an adaptation to the cold, high altitude environment in which they are found in the mountains of C China. A reduction in the elongation of internodes within the inflorescence and an increase in the number of paraclades of shorter spikelets on shorter pedicels forces them to assume a dense, horizontal, downward-facing arrangement under a roof of imbricating leaf sheaths protecting them from frost and snow.
The genus Sinarundinaria Nakai was published for cultivated plants of F. nitida and F. murielae sent from Kew to Japan. Flowering of both species has confirmed that they belong in Fargesia, where Sinarundinaria is now placed as a synonym. Sinarundinaria was for a while used in a very broad sense covering the genera Yushania, Drepanostachyum, Himalayacalamus, Chimonocalamus and Otatea as well as Fargesia nitida, assuming that F. nitida would have open inflorescences, which it does not.
Yi, T.P. (1988). A study on the genus Fargesia Franch. from China. J. Bamboo Res. 7(2): 1–119.
Stapleton, C.M.A. (2006). New taxa and combinations in cultivated bamboos (Poaceae: Bambusoideae). Sida 22(1): 331–332.
Stapleton, C.M.A. (2021). We need to talk about Fargesia: new combinations and a new genus in the temperate Sino-Himalayan bamboos (Poaceae: Bambusoideae). J. Amer. Bamboo Soc. 31: 1-16.
|
