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Taiwan Gramineae | Family List | Poaceae

Eragrostis Wolf, Gen. Pl. 23. 1776.

畫眉草屬

Eragrostis amabilis
autofluorescence leaf cross section

Credit: CS Kuoh

Annuals or perennials, culms slender, tufted, mostly erect; ligule short, truncate, ciliate. Blade narrowly linear. Inflorescence an open or contracted, sometimes spike-like or even head-like panicle. Spikelets strongly laterally, compressed, 2-numerous-flowered, rarely only 1 fertile flower with sterile lemma above the floret. Florets all bisexual or upper ones reduced, rarely otherwise; rachilla zigzag, or straight, tough or gradually breaking up at maturity, in the former case florets deciduous or paleas persistent; in the latter case florets deciduous with adjacent internode of rachilla; glumes equal or lower glume 1-3nerved; lemma ovate or ovate-oblong, rounded on back, with acute, obtuse or truncate apex, glabrous or scabrous, sometimes with tubercule-based hairs on lateral nerves, rarely with short straight awn, 3-nerved, the nerves longer or shorter, sometimes obscure; palea equaling lemma or shorter, more or less curved, 2-nerved, with 2 ciliated or eciliated keels, deciduous with lemmas or tardily dropping off; lodicules 2; stamens 2-3; ovary glabrous, the styles 2, short, the stigmas exserted lateraily. Caryopsis enclosed in. lemma, globose, ellipsoid or oblong; embryo 1/2 as long the caryopsis, longer or shorter, the hilum punctiform, basal.

About 300 species distributed all over the world, mostly in subtropic regions.

16 species are found in Taiwan, mainly growing on the plains and open dry area.


KEY TO THE SPECIES

1 Florets articulate from above downwards, falling together with the rachilla-joints; caryopsis smooth, circular in X-section; spikelets less than 2 mm long.   (2)
+ Florets falling off from below upwards, but leaving the continuous rachilla; caryopsis with reticulate or tessellate markings; spikelets more than 2 mm long.   (4)
       
2 (1) Inflorescence a spike-like contracted panicle; cilia of palea soft, longer than the width of the palea   Eragrostis ciliaris
+ Inflorescence a more or less open panicle.   (3)
       
3 (2) Cilia of the lemma 1/2 as long as the lemma; axil of panicle branches with glands; culms geniculate at basal nodes   Eragrostis amabilis
+ Cilia of the lemma very short, scabrous; axils of panicle branches glabrous; plant devoid of glands; culms erect   Eragrostis japonica
       
4 (1) Caryopsis tesselate, subglobose; blades margins and spikelet glandular.   (5)
+ Caryopsis with netted marking on surface, ovoid in outline, if tessellate then cylindrical and circular or triangular in X-section; blades margins and spikelet eglandular.   (6)
       
5 (4) Spikelets 1.5-2 mm wide; lemmas 1.5-2 mm long   Eragrostis minor
+ Spikelets 2-3 mm wide; lemmas 2-2.2 mm long   Eragrostis fauriei
       
6 (4) Caryopsis compressed; elliptical in X-section.   (7)
+ Caryopsis tessellate or pitted, circular or bluntly triangular in X-section. .   (11)
       
7 (6) Panicle contracted, spiciform; anthers 0.5 mm long.   (8)
+ Panicie open; anthers less than 0.3 mm long.   (9)
       
8 (7) Axils of panicle branches long ciliate; paleas entire, straw-colored; keels ciliated   Eragrostis cylindrica
+ Axils of panicle branches glabrous; paleas with two-teeth, purprish; keels shortly ciliate   Eragrostis nevinii
       
9 (7) Spikelets widely compressed, ovate, more than 2-4 mm wide, straw or reddish in color   Eragrostis unioloides
+ Spikelets less than.2 mm wide, lanceolate to linear.   (10)
       
10 (9) Lemmas obtuse, mucronate; axils of panicle branches more or less pilose; blades pilose, less than one- third as long as the plant   Eragrostis pilosiuscula
+ Lemmas acute; axils of panicle glabrous; blades not pilose, longer than one-half the length of the plant   Eragrostis bulbillifera
       
11 (6) Caryopsis furrowed on one side, bluntly triangular in X-section.   (12)
+ Caryopsis tessellate, circular or elliptical in X-section.   (13)
       
12 (11) Plant eglandular; leaves pilose   Eragrostis pilosissima
+ Plant glandular; leaves nearly glabrous   Eragrostis ferruginea
       
13 (11) Anthers about 0.2 mm long; spikelets less than 1.5 mm wide; annuals.   (14)
+ Anthers longer than 0.5 mm long; spikelets more than 1.8 mm wide; perennials.   (15)
       
14 (13) Axils of panicle branches and sheath-mouth pilose   Eragrostis pilosa
+ Axils of panicle and sheath-mouth not piiose   Eragrostis multicaulis
       
15 (13) Caryopsis elliptical in X-section; palea persistent; leaves 2.5 mm wide   Eragrostis fauriei
+ Caryopsis circular in X-section; palea deciduous; leaves 1.5 mm wide   Eragrostis nutans

  • List of lower taxa


     

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