瑞沃达早熟禾Poa reverdattoi Roshev.

科名：禾本科 Gramineae

属名：早熟禾属 Poa

《中国植物志》第9(2)卷196页
  176．瑞沃达早熟禾（拟）图版17：1
  Poa reverdattoi Roshev. in Acta Inst. Bot. Ac. Sc. URSS Ser. I, II. 13a. 1934. et in Kom. Fl. URSS 2: 407, Pl. 30. fig. 1934. ——Poa glauca subsp. reverdattoi(Roshev. )Tzvel. in Fed. Poac. URSS 476. 1976.
  多年生，密丛型。秆直立，高30-40厘米，质硬，粗糙，上部裸露，无叶；叶舌长圆形，长1-2毫米；叶片扁平或对折，长约8厘米，宽0.5-1.2毫米，基生叶丰富，粗糙。圆锥花序较狭窄，长约8厘米，宽0.5-1厘米；分枝长约2厘米，粗糙，贴生，后稍伸展；小穗长4-5毫米，含2-4小花，黄绿色；两颖狭披针形，近等长，长3-3.2毫米，3脉不明显，先端尖，边缘膜质；外稃长3.5-4毫米，脊与边脉中部以下具较长柔毛，基盘无绵毛。花期7月。
  产内蒙古。生于中高山石质山坡草地。分布于俄罗斯西伯利亚、蒙古。模式标本采自蒙古。

《Flora of China》 Vol. 22 (2006)
Poa versicolor subsp. reverdattoi  (Roshevitz) Olonova & G. Zhu
瑞沃达早熟禾   rui wo da zao shu he
Basionym: Poa reverdattoi Roshevitz in Komarov, Fl. URSS 2: 407. 1934; P. argunensis Roshevitz.
Culms densely tufted, (15–)35–45(–60) cm tall, erect, scabrid, sometimes tinged with grayish green, terminal node 1/6–1/3 way up culm. Leaf sheaths scabrid, shorter than internode, terminal sheath ca. 2 × as long as blade; blades folded or inrolled, hard, short, 0.5–1(–1.5) mm wide, abaxial surface and margin scabrid, adaxial surface minutely hairy; ligule (1–)2–2.5(–3) mm. Panicle contracted to spiciform, laxer at anthesis, 3–4 × (0.5–)1–5(–8) cm, branches 2 or 3 per node, with spikelets near base. Spikelets sometimes tinged with purple, 3–5(–6) mm, florets 2–4; rachilla glabrous or pilulose; glumes (2–)2.8–3(–3.5) mm; lemma keel shortly villous for 1/2 length, marginal veins for 1/3, area between veins minutely hairy for lower 1/3; callus usually moderately webbed to glabrous; palea minutely hairy in lower area between keels. Anthers ca. 2 mm. Fl. Jun. 2n = 28, 35, 42.
Dry grasslands on rocky slopes; 200–1000 m. Liaoning, Nei Mongol [Mongolia, Russia (S Siberia)].
This is a variable subspecies with a rather restricted distribution limited to low elevations of China, Mongolia, and S Siberia. Records of this subspecies from Xinjiang and the Altai region belong to Poa albertii.

Poa argunensis differs from subsp. reverdattoi only in variable and unreliable characters and forms many intermediate populations.