Actinocladum McClure ex Soderstrom (1981: 1902)

Lopes-Neto, Raimundo Balieiro & Viana, Pedro Lage, 2022, Flora of the Serra do Cachimbo (Eastern Amazon, Brazil): Bambusoideae (Poaceae), including the description of two new species, Phytotaxa 550 (2), pp. 99-129 : 102

Actinocladum McClure ex Soderstrom (1981: 1902) .

TYPE:— Actinocladum verticillatum (Nees 1829: 523) McClure ex Soderstrom (1981: 1204) .

Plants cespitose. Culms homomorphic, erect, 2–5 m tall, infra- and supranodal bands of trichomes absent. Branch complement apsidate (fan-shaped), all about equal in length, unbranched, without thorns. Culm leaves and foliage leaves clearly distinct. Culm leaves dimorphic, midculm leaves with blades erect and flat when young, then becoming patent and concave at maturity, narrower than the sheath summit, sheaths with ruffle-like fused fimbriae at the apex; terminal culm leaves with convex, often reflexed blades, larger than the midculm leaf blades, sheaths puberulent. Foliage leaf sheaths with fimbriae at the apex or not, translucent swelling absent, outer ligule present, blades linearlanceolate, midnerve not prominent. Synflorescence terminal, paniculate or racemose, branched, often with secondary branches; spikelets long-pedicelled, bisexual, glumes 2 (rarely 3), many-flowered, anthecium smooth, the terminal one smaller than the others. Fruit a nucoid caryopsis, hilum broad-linear.

Actinocladum is a monospecific genus of woody bamboo, easily recognized by its aspidate branch complement and dimorphic culm leaves (midculm leaves vs terminal leaf complement) ( Soderstrom 1981). In Brazil, it occurs in the Amazon, Cerrado and Pantanal phytogeographic domains (Andrade et al. 2020).