Raddiella minima Judziewicz & Zuloaga (1991: 939)

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 : 124

Raddiella minima Judziewicz & Zuloaga (1991: 939) . Fig. 7 M–N .

Type:— BRAZIL. Pará: Município de Itaituba , km 771 estrada Santarém-Cuiabá próximo a divisão Pará-Mato Grosso, mata de cerrado solo pedregoso, vegetação rupestre, 9°35’S, 54°35’W, 22 April 1983, Amaral 883 (holotype INPA!, isotypes MO, NY) .

Rhizomes absent. Culms 3–6 cm long, filiform, geniculate, multi-branched, internodes ca. 5 mm, smooth, glabrous; nodes dark brown, with a few very short retrorse trichomes. Leaf sheaths ca. 2 mm, glabrous to short-pilose, the upper margins ciliate, fimbriae absent; ligules ca. 0.2 mm, membranous; pseudopetioles 0.1–0.2 mm long, glabrous to shortpilose; blades 4–6 × 2.7–3.3 mm, ovate-triangular, delicately membranous, glabrous, asymmetrical, base truncate, margins scaberulous, apex acute or apiculate. Terminal synflorescences ca. 10 mm long, with a single male spikelet. Axillary synflorescences ca. 3 mm long, female spikelets 2(–3). Male spikelets ca. 1.3 mm long, elliptical, hyaline, glabrous, the lemma soon caducous. Female spikelets 1–1.4 mm long, lanceolate-ovoid, glabrous to short-hispid, delicately membranous; lower glume 3-nerved, apex acuminate; upper glume 3-nerved, apex acuminate; anthecium 0.9–1.2 mm long, ovoid, white becoming dark, dorsally compressed, smooth and shiny, caducous. Caryopsis not seen.

Specimens examined: — BRAZIL. Pará : Itaituba, Estrada Santarém-Cuiabá, BR 163, Km 771, próximo a divisão Pará-MT, 22 April 1983, Amaral 883 ( INPA, MO) .

Additional specimens examined: — BRAZIL. Amazonas : Canutama, Joana D’Arc, 95m, 8°39’27”S, 64°21’39”W, 23 April 2007, Viana et al. 2634 ( INPA) .

Distribution and habitat: —This species is endemic to Brazil, in the states of Amazonas, Mato Grosso and Pará ( Zuloaga & Judziewicz 1991, Oliveira & Oliveira 2020). In the Serra do Cachimbo, it was found in Campo rupestre near the borders of Mato Grosso and Pará States ( Zuloaga & Judziewicz 1991).

Comments: — Raddiella minima is one of the smallest bamboos of the world (Zuloaga & Judziewicz 1993, Judziewicz & Sepsenwol 2007), with filiform culms 3–6 cm long, ovate-triangular leaves, asymmetrical, glabrous, base truncate and apex acute to apiculate. It can be distinguished from R. esenbeckii by the shorter culms, blades 0.4–0.6 cm long, the axillary synflorescences bearing only female spikelets and ovoid-globose caryopsis, with the hilum punctiform, central.

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.