Oropetium Trinius 1820
Creators: name: Shinde, Rajendra D.
name: Landge, Shahid Nawaz
name: Kulloli, R. N.
name: Chorghe, Alok R.
Publisher: name: Zenodo
Year: 2023
Subjects: Biodiversity
Taxonomy
Plantae
Tracheophyta
Liliopsida
Poales
Poaceae
Oropetium

description: Key to the species of Oropetium in the world
1. Rhachis fragile, readily or tardily disarticulating into spiculated segments (African & Arabian species; exceptionally including O. almeidanum) ......................................................................................................................................................................................2
1. Rhachis not fragile, not disarticulating into spiculated segments, apparently tough and persisting (Indian species)........................5
2. Annual; butt sheaths lacking at the base of the culm ...................................................................................................... O. aristatum
2. Perennial; butt sheaths persistent at the base of the culm ..................................................................................................................3
3. Spikes straight or curved, never flexuous; rhachis bilaterally flattened not triangular in transverse section, spikelets in two subopposite rows; upper glume apex acute or long-acuminate (apex 2.5 mm long), never awned ........................................................4
3. Spikes straight or flexuous; rhachis not bilaterally flattened, triangular in the transverse section, spikelets in two rows disposed just side by side (adjacent); upper glume apex acuminate to long awned (awn 2–18 mm long)........................................... O. minimum
4. Spikelets 2.0–3.0 (–4.0) mm long; upper glume nerves not ribbed, apex acute; lemma 1.5–2.0 (–2.5) mm long; palea apex without excurrent keel nerves; caryopsis 1.0– 1.5 mm long ............................................................................................................ O. capense
4. Spikelets 4.0–6.0 mm long; upper glume 4.0–5.3 × 0.8 mm, nerves strongly ribbed, apex long-acuminate; palea apex with two conspicuous excurrent keel nerves and broadly winged; caryopsis up to 1.8 mm long............................................. O. almeidanum
5. Annual; spikes 1.0– 3.5 cm long; one flowered spikelet without a rachilla extension .......................................................................6
5. Perennial; spikes more than 4.0 cm long; usually one flowered, sometimes also two flowered spikelet then with a conspicuous rachilla extension................................................................................................................................................... O. roxburghianum
6. Butt sheaths absent at the base of the culms; spikes terete, not with a distinct saw-toothed appearance, up to 1.5 cm long, subtended by a spathaceous sheath at the base; lemma villous on the dorsal side......................................................................... O. villosulum
6. Butt sheaths persistent, somewhat fibrous at the base of the culms; spikes laterally compressed, with a distinct saw-toothed appearance, 1.5–3.5 cm long, not subtended by a spathaceous sheath at the base; lemma glabrous on the dorsal side...................... ....................................................................................................................................................................................... O. thomaeum
description: Published as part of Shinde, Rajendra D., Landge, Shahid Nawaz, Kulloli, R. N. & Chorghe, Alok R., 2023, Oropetium almeidanum (Poaceae: Chloridoideae): a new species from The Thar Desert, Rajasthan, India, pp. 267-277 in Phytotaxa 579 (4) on page 275, DOI: 10.11646/phytotaxa.579.4.4, http://zenodo.org/record/7563980