Isachne GRAMINEAE Digitaria 



turned towards the rachis 63. Paspalum 



Back of the fertile lemma turned away from 

 the rachis, first glume and rachilla joint 

 forming a swollen ring-like callus below 

 the spikelet 64 . Eriochloa 



56. Isachne R.Br. |||| (Liu Yeh Jo Shu) 

 Perennials or annuals with flat blades and terminal panicles: spikelets 2-fld., 

 disarticulating above the glumes, which are sub-equal and about as long as the 

 spikelet: florets indurate and planoconvex, or the lower floret stamina te, with 

 membranaceous lemma. More than 80 species, in tropical and temperate zones; 8 

 in China. (Greek: isos, and achne, chaff, alluding to the similar lemmas of the type 

 species.) 



Key to the Species 



Blades linear-lanceolate, 2-13cm. long: spikelets 2. 0-2. 5mm. long 1. i". globosa 



Blades ovate-lanceolate, 1.0-2.5 cm. long: spikelets about 1.5 mm. long. .. . 2. I. pulchella 



1. Isachne globosa (Thunb.) Ktze. WMW ( Liu Yeh J°J Willow-leaved Bamboo) 

 (Mak.F.833). Spreading perennial with ascending brs. 20-60 cm. high; fls. VI; 

 fr. VII. India to Japan, and south to Australia; locally in An., Che., Ku. 

 Ditches and moist ground. 



2. Isachne pulchella Roth (Be. F. 414). Prostrate annual with ascending brs. 

 Southeastern Asia; locally in Che. Streamsides and rice fields. 



" This Isachne pulchella Roth and Sphaerocaryum (a single species) were confused. 

 Supeificially they resemble each other. The name 'Isachne polygonoides (Lam.) Doell, ' a 

 species described from French Guiana and found in Brazil, was misapplied to the true Isachne 

 pulchella." — Agnes Chase. 



57. Digitaria Heister Crabgrass ft^M (Chih Ts'ao 

 Shu; Finger-grass Genus) 



Annuals (ours) with subdigitate spikelike racemes: spikelets 1-fld. subsessile, in 

 two rows on one side of a continuous rachis, disarticulating beloiv the glumes: first 

 glume minute or wanting; second glume similar to the sterile lemma or smaller; 

 fertile lemma indurate, with hyaline flat margins, enclosing a palea of like texture. 

 More than 100 species, chiefly in the warmer parts of the Old World; 14 in China. 

 (Latin: digitus, finger, alluding to the digitate inflorescence of the type species, 

 D. sanguinalis.) 



Key to the Species 



a. Spikelets elliptic; second glume about as long as the sterile lemma; 

 fertile floret dark brown at maturity. 



Spikelets 2. 0-2. 2mm. long; first glume hyaline, evanescent 1. D. ischaemum 



Spikelets 1.5-1.8 mm. long: first glume wanting 2. D. violascens 



aa. Spikelets narrowly lanceolate; second glume 1/2-3/4 the length of 

 the sterile lemma; fertile floret pale or lead-colored at maturity. 

 Culms usually stout: racemes 3-10, relatively rigid. 



Hairs of the sterile lemma giayish, appressed even at maturity 3. D. sanguinalis 



Hairs of the sterile lemma fulvous, spieading at maturity 3a. D. sanguinalis 



var. ciliaris 

 Culms slender and delicate: racemes 2-4, rather lax 4. D. chinensis 



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