Chusquea sect. Tenellae Incertae Sedis

Attigala, Lakshmi, Fuentes, Alfredo F. & Clark, Lynn G., 2017, Chusquea sect. Tenellae (Bambuseae, Bambusoideae, Poaceae), a taxonomic revision of a new section from South America, Phytotaxa 324 (3), pp. 239-265 : 262-263

Chusquea sect. Tenellae Incertae Sedis

C. tenuiglumis var. laxiuscula Döll (1880: 200) . Lectotype (here designated):— BRAZIL. Minas Gerais: Lagoa Santa, May 1865 (fl), Warming s.n. (C! label handwritten, with the locality in red ink, isolectotype C! typeset collector name and locality, the date handwritten in red ink). This collection consists of just these two sheets, the lectotype consisting of a leafy flowering branch and the isolectotype consisting of a branch complement bearing leafy flowering branches and non-leafy synflorescences. This entity shares more in common with C. tenella than with C. tenuiglumis in terms of synflorescence branching and size, but the foliage leaf blades lack the basal pubescence on the abaxial surface characteristic of C. tenella so we exclude it from our concept of that species. Additionally, the northernmost verified population of C. tenella is in southern São Paulo state (Clark & Windisch 725, Joly s.n.), so this collection from Lagoa Santa would represent a significantly disjunct population if treated as that species. Despite the broad distribution of C. ramosissima , this collection is unlikely to represent that species, as its foliage leaf blades are 9–12.5 × 1.1–1.8 cm wide vs. 4–9.4 (–12) × 0.5–1.5 (–1.8) cm in C. ramosissima , and glumes III and IV extend only about 1/2 the spikelet length, vs. 2/5 to 2/ 3 in C. ramosissima . To our knowledge, this population has not been recollected since the original collection, but field work to obtain a complete vegetative collection is needed to determine its status.

Chusquea sp. indet. BOLIVIA. Dep. La Paz , Prov. Sud Yungas, Chulumani 107 km hacia NNE, pasando Asunta, Alto Charia sobre el río San José, afluente del Río Boopi, 900 m, 6 August 1983 (fl), Beck 8517 ( K, LPB) ; Dep. La Paz , Prov. Nor Yungas, por debajo de Yolosa, ca. 2 km arriba del embarcadero, al sur del río Huarinillas, 16°12’09”S, 67°46’22”W, 1250 m, 4 August 1991, Beck 18797 ( K, LPB). These two collections, from parallel valleys, almost certainly represent a new species within sect. Tenellae , but the material is too incomplete to describe adequately. The culm leaf is persistent, branching is infravaginal, the subsidiary branches are of two sizes, the relatively large foliage leaves (the two complete leaf blades on Beck 8517 measure 16 × 4.3 cm and 10.5 × 2.8 cm) have strongly excentric midribs, and the thin-textured spikelets are ca. 13 mm long with glumes I and II scale-like and relatively short, and glumes III and IV 1/3–1/2 the length of the spikelet .