Raddiella malmeana ( Ekman 1911: 21 ) Swallen (1948: 89)

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 : 123-124

Raddiella malmeana ( Ekman 1911: 21) Swallen (1948: 89)

≡ Olyra malmeana Ekman (1911: 21) . Fig. 7 J–L .

Type:— BRAZIL. Mato Grosso: Santa Ana da Chapada , Buriti, in proruptis rupis ad cataractam junta cum Sphagni, 16 June 1894, Malme 1684 (holotype S, isotype US) .

Rhizomes absent. Culms 11–28 cm tall, decumbent and rooting at the lower nodes, forming low mats, internodes 1.2–1.4 cm, pithy in center, smooth, glabrous; nodes glabrous. Leaf sheaths glabrous, margins membranous, with short trichomes in the apex, ca. 0.3 mm long, fimbriae absent; ligules ca. 0.3 mm, membranous; pseudopetioles ca. 0.3 mm, glabrous; blades 1.1–1.2 × 0.3–0.4 cm, elliptical, delicately membranous, short-pilose on both surfaces, symmetrical, base acute, margins scaberulous, apex acute. Terminal synflorescences ca. 5 mm long, with a single male spikelet, rachis glabrous, pedicels ca. 2 mm long, filiform, glabrous. Axillary synflorescences 0.9–1 × 0.2 cm, female spikelets 2–4, rachis glabrous, pedicels 0.2–0.4 mm, filiform, glabrous. Male spikelets ca. 3 × 0.8 mm, lanceolate, hyaline, short-pilose toward the apex, falling entire; lemma 3-nerved; palea 2-nerved; stamens 2, exserted, filaments ca. 1–2 mm long, glabrous, anthers ca. 2 mm long, yellowish. Female spikelets ca. 2 × 0.7 mm, narrowly ovoid, white, shorthispid, delicately membranous, falling entire; lower glume ca. 2 × 0.6 mm, 5-nerved, delicately membranous, shorthispid, with long trichomes mainly on the nerves, apex acuminate; upper glume ca. 2 × 0.6 mm, 5-nerved, delicately membranous, short-hispid, with long trichomes mainly on the nerves, apex acuminate; anthecium ca. 1.3 × 0.6 mm, narrowly ovoid, white, compressed, delicately membranous, deciduous; lemma 2-nerved, glabrous, apex acute; palea 2-nerved, glabrous, apex acute; ovary 0.3–0.6 mm tall, elliptic, glabrous, style ca. 0.6 mm, glabrous, membranous in the base, stigma 2, plumose. Caryopsis not seen.

Specimens examined: — BRAZIL. Pará: Altamira, Reserva Biológica Nascentes da Serra do Cachimbo , Cachoeira do Rio Curuá, 8°44’05.7”S, 54°57’42.5”W, 30 September 2019, Lopes-Neto et al. 558 ( MG) . Itaituba: Estrada Santarém-Cuiabá, BR-163, km 877, Cachoeira da Luz , rio Curuá, margem esquerda, 02 May 1983, Amaral 1072 ( INPA) ; Vale de solo pedregoso, embaixo da Cachoeira da Luz do Rio Curuá , 02 May 1983, Silva 196 ( INPA) . Novo Progresso: Campo de Provas Brigadeiro Velloso , Cachoeira da Harpia, 01 October 2019, Lopes-Neto et al. 569 ( MG) ; Toca das Ariranhas, 451 m, 9°21’45.4”S, 54°54’09.2”W, 451m, 27 May 2021, Lopes-Neto et al. 751 ( MG) .

Distribution and habitat: —This species is endemic to Brazil, and grows on humid rocks near streams, usually associated with waterfalls, in the states of Mato Grosso and Pará ( Zuloaga & Judziewicz, 1991, Oliveira & Oliveira 2020). In the Serra do Cachimbo, it was found in Open ombrophilous forest, in the Curuá (REBIONSC), Harpia and Toca das Ariranhas (CPBV) waterfalls.

Comments: — Raddiella malmeana is mainly characterized by the decumbent culms, rooting in the lower nodes and forming low mats. It can be distinguished from the other congeners in the Serra do Cachimbo by its symmetrical, elliptic leaves with base and apex acute (vs. ovate-triangular, asymmetrical leaves with base truncate and apex acute, apiculate or short-apiculate), short-pilose on both surfaces or scabrous on the abaxial surface (vs. glabrous or shortpilose near the base on the adaxial surface, to densely puberulent on both surfaces) and female spikelets falling entire (vs. female spikelets with persistent glumes).

Figures

FIGURE 7. Field photographs of bamboos from Serra do Cachimbo. A–B. Olyra caudata: A. Habit. B. Synflorescence. C–D. Olyra latifolia: C. Habit. D. Synflorescence.E–G. Olyra taquara: E. Habit.F. Leaf. G. Detail of the synflorescence. H–I. Raddiella esenbeckii: H. Habit. I. Synflorescences. J–L. Raddiella malmeana: J. Habit. K.Axillary synflorescences. L. Terminal synflorescences. M–N. Raddiella minima [Viana et al. 2634 (INPA)]: M–N. Habit. Photos: P.L.Viana.