The grass genera of the world

L. Watson, T.D. Macfarlane, and M.J. Dallwitz

Froesiochloa G.A. Black

Named for R.L. Fróes, botanical explorer of the Amazon region.

Habit, vegetative morphology. Perennial. The flowering culms leafy. Culms herbaceous. Leaves not basally aggregated; without auricular setae. Leaf blades lanceolate to ovate (?); pseudopetiolate; rolled in bud. Ligule an unfringed membrane.

Reproductive organization. Plants monoecious with all the fertile spikelets unisexual; without hermaphrodite florets. The spikelets of sexually distinct forms on the same plant; female-only and male-only. The male and female-fertile spikelets mixed in the inflorescence (a central female surrounded by 6–10 males, in each cluster). The spikelets overtly heteromorphic (the female spikelets lanceolate).

Inflorescence. Inflorescence without pseudospikelets; a false spike, with spikelets on contracted axes (of 2–4 deciduous clusters on a central axis). Spikelet-bearing axes disarticulating; falling entire (the clusters falling).

Female-sterile spikelets. Male spikelets 1 flowered, lemma membranous and 3 nerved, lodicules 3, 6 stamens with joined filaments. Rachilla of male spikelets terminated by a male floret. The male spikelets without glumes; without proximal incomplete florets; 1 floreted. The lemmas awnless. Male florets 1; 6 staminate. The staminal filaments joined.

Female-fertile spikelets. Spikelets lanceolate; compressed dorsiventrally; falling with the glumes (i.e. with the clusters). Rachilla terminated by a female-fertile floret.

Glumes two; about equalling the spikelets to exceeding the spikelets; long relative to the adjacent lemmas; pointed (acuminate, herbaceous); awnless; non-carinate; similar. Lower glume 3–7 nerved. Upper glume 3–7 nerved. Spikelets with female-fertile florets only.

Female-fertile florets 1. Lemmas decidedly firmer than the glumes (leathery); entire; pointed (‘subacute’); mucronate; non-carinate; 5–7 nerved. Palea present; awnless, without apical setae; 2-nerved, or several nerved (?). Lodicules present; 3. Stamens 0. Ovary apically glabrous.

Fruit, embryo and seedling. Disseminule consisting of the disarticulated spikelet-bearing inflorescence unit.

Classification. Watson & Dallwitz (1994): Bambusoideae; Oryzodae; Olyreae. Soreng et al. (2015): Bambusoideae; Bambusodae; Olyreae; Olyrinae. 2 species.

Distribution, phytogeography, ecology. Brazil, Guiana.

Mesophytic; shade species. In forests.

References, etc. Morphological/taxonomic: G.A. Black (1950: not yet seen - data here from Clayton and Renvoize 1986).

Special comments. Fruit data wanting. Anatomical data wanting.

We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, distributions of character states within any set of taxa, geographical distribution, and classifications. See also Guidelines for using data taken from Web publications.

Cite this publication as: ‘Watson, L., Macfarlane, T.D., and Dallwitz, M.J. 1992 onwards. The grass genera of the world: descriptions, illustrations, identification, and information retrieval; including synonyms, morphology, anatomy, physiology, phytochemistry, cytology, classification, pathogens, world and local distribution, and references. Version: 11th December 2017.’.