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Taiwan Gramineae | Family List | Poaceae

Digitaria Haller

馬唐屬

Digitaria magna
drawing

Credit: CC Hsu

Annuals or perennials; culms hollow or solid; erect, ascending or creeping; shoots intravaginal. Sheaths of leaf often loose from culm; ligule well-developed, membranaceous; blades linear to lanceolate, with broad base and acute tip, flat, soft. Inflorescence branched from all sides, composed of 2- numerous spike-like racemes. Spikelets crowed, alternately 2-3-together along keel, unequally pedicelate in a group, sometimes subsessile, articulate with widened tip of pedicel, dorsally compressed, linear- lanceolate to obovate, small, 2-flowered, muticous, usually equal in from and size; lower glume absent or very small, hyaline and veinless, rarely faintly 1-veined; upper glume very veriable in length, thin, hyaline and veinless, rarely faintly 1-neined; lower lemma as long as spikelet, rarely shorter, 5-9- veined; lower palea absent or very small and adnate to base of upper lemma; upper lemma as long as spikelet or slightly shorter, papery with broadly inflexed, hyaline or pale margins, densely striate and very finely tuberculate, often olive-green, brown or dark purple at maturity, glabrous; upper palea as long and of same texture, 2-veined, with inflexed margins, embraced to apex by margins of upper lemma; lodicules very small, cuneate; stamens 3; style 2, free; stigmas plumose, exserted at or near apex. Caryopsis tightly enclosed by only slightly indurate upper palea and lemma, elliptic, dorsaly compressed, hilum punctiform, embryo at most 1/2 as long as caryopsis.

A large genus of ca. 230 species distributed in the warmwe parts of the world; 13 species and two varieties are found mainly on the plains of Taiwan.


1 Spikelets 2.5-4 mm long, acuminate, narrowly lanceolate; pedicels winged.   (2)
+ Spikelets to 2.2 mm long, acute, elliptic or ovate; pedicels terete, smooth.   (9)
       
2 (1) Rachis triangular, shining; spikelets dimorphic; lower lemma with veins much broader than space between veins.   Digitaria heterantha
+ Rachis flat; spikelets monomorphic; lower lemma with fine veins.   (3)
       
3 (2) Racemes closely contracted; spikelets ca. 2.5 mm long   Digitaria henryi
+ Racemes partially contracted or spreading.   (4)
       
4 (3) Margins of rachis-wing entire or serrulate.   Digitaria radicosa
+ Margins of rachis-wing distinctly serrate.   (6)
       
5 Leaves glabrous, base of blades scattered with long hairs; in shady soils.   Digitaria radicosa var. radicosa
+ Leaves densely hirsute; in rocy cliffs   Digitaria radicosa var. hirsuta
       
6 (4) Lower glume absent; upper glume less than 1/3 length of spikelet.   Digitaria setigera
+ Lower glume small but distinct, ovate; upper glume more than 1/2 length of spikelet.   (7)
       
7 (6) Plant hairy; nodes beared; upper glume ca. 3/4 length of spikelet   Digitaria sericea
+ Plants glabrous; nodes glabrous; upper glume 1/2 long or longer than spikelet.   (8)
       
8 (7) Spikelets 3 mm long; intervein spaces of lower lemma evenly distributed.   Digitaria ciliaris
+ Spikelets 3-3.5 mm long; intervein spaces of lower lemma broader at middle   Digitaria sanguinalis
       
9 (1) Upper florets pale at maturity.   (10)
+ Upper florets brown at maturity.   (12)
       
10 (9) Culms stoloniferous; sheaths more or less pubescent, at least lower ones; spikelets 1.2-1.5 mm long; racemes 2-6 mm long   Digitaria longiflora
+ Culms erect or decument; sheaths villous; spikelets 1.5-2.2 mm long.   (11)
       
11 (10) Racemes 3-5 mm long; blades 2-6 cm long.   Digitaria mollicoma
+ Racemes 5-10 mm long; blades 7-10 cm long.   Digitaria magna
       
12 (9) Spikelets 1.2-1.5 mm long, distinctly shorter than pedicel; upper florets light brown   Digitaria leptalea var. reticulmis
+ Spikelets as long as or longer than pedicel; upper florets brownish.   (13)
       
13 (12) Upper glume 1/4-1/2 length of spikelet.   Digitaria fauriei
+ Upper glume about same length of spikelet.   (14)
       
14 (13) Spikelets ca. 1.8 mm long   Digitaria violascens
+ Spikelets more than 2 mm long   Digitaria ischaemum

  • List of lower taxa


     

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