Acroceras

Acroceras is a genus of herbaceous plants in the Poaceae family. It is native to Africa, temperate or tropical regions of Asia, North America and South America.

Description

They are prostrate perennials or annuals; stems up to 2 m tall, with roots emerging from the lower nodes, freely branching; internodes glabrous, smooth, thick-walled, fistulous; glabrous or hispido-papillose nodes especially near apex; polygamous plants. stem leaves; pods rounded, glabrous or papilloso-hispid; pseudoligule ca 0.2 mm long, ligule a membrane, 0.2–0.5 mm long; blades lanceolate-ovate, 8–10 cm long and 8–35 mm broad, flattened, cordate at base, glabrous or sometimes papilloso-hispid; short pseudopetiolate. Inflorescence a panicle of divergent racemes, 9–35 cm long and 2–10 cm broad, the spikelets mostly paired, one brevipedicelate, the other longipedicelate; spikelets large, elliptical-ovate, 5.5–6.6 mm long, appressed, apiculate, glabrous, with 2 florets, disarticulating below glumes, spikelet drooping as a unit; lower glume 4–5.4 mm long, 3–5-veined, amplexicaule; upper glume and lower lemma 5–6 mm long, herbaceous, 5-veined, the apices laterally compressed; lower floret staminate, the anthers ca 2 mm long; lower lemma 4.5–5.4 mm long, 5-veined, inferior palea well developed, 3.5–4 mm long, membranaceous; upper floret bisexual, 4.5–5 mm long, smooth, glossy; upper lemma rigid, smooth, with a laterally flattened rostrum, herbaceous, green, with a circular depressed area on the dorsal part above the base, the margins thickened not involute; upper palea flattened, rigid, the apex with a small, flattened, 2-toothed, herbaceous rostrum; rachilla thick and hardened, with well defined internodes between glumes and between upper glume and lower lemma; lodicules 2; stamens 3, the anthers 2 mm long, purplish; styles 2. Fruit a caryopsis; embryo ca 1/2 or more length of caryopsis; short or long linear thread.

Taxonomy

The genus was described by Stapf in Prain and published in Flora of Tropical Africa 9: 621. 1920. The type species is: Acroceras oryzoides Stapf

Etymology

Acroceras: generic name derived from the Greek words akros (at the top) and keras (horn), alluding to crested mottos.

Cytology

It has a chromosome number of: x = 9. 2n = 36.

Species

• Acrocera amplectens Stapf
• Attenuatum acrocera Renvoize
• Basiccrops Stapf
• Boivinii acrocers (Mez) A.Camus
• Acroceras bosseri A.Camus
• Calcicola acrocers A.Camus
• Acroceras chaseae Zuloaga et Morrone
• Crassiapiculatum acrobats (Mr.) Alston
• Difusum acrocers L.C.Chia
• Elegan acrocers A.Camus
• Excavatum acrocers (Henrard) Zuloaga et Morrone
• Flumine acrobats (Hack.) Zuloaga et Morrone
• Gauntian acrocers (Hack.) Clayton
• Hubbardii crores (A.Camus)Clayton
• Rihibense acrobats A.Camus
• Acroceras lateriticum A.Camus
• Acroceras macrum Stapf
• Mandrarense acrobats A.Camus
  • Mandrarense ssp eromoense A.Camus
  • Mandrarense ssp mananarense A.Camus
• Manongarivense acrocers A.Camus
• Munroanum acrocers (Balansa) Henrard
• Oryzoid acrocers Stapf
• Acrocera parvulum A.Camus
• Paucispicatum acrocera (Morong) Henrard
• Acroceras pilgerianum Schweick.
• Acroceras ridleyi (Hack. ex Ridl.) Stapf
• Sambiranian acrocera A.Camus
• Acrocera seyrigii A.Camus
• Sparsum snacks Stapf
• Acrocera tenuicaule A.Camus
• Tonkinian acrocers (Balansa)Henrard
• Zizanioid acrocers (Kunth) Dandy