Dichanthelium portoricense
Dichanthelium perlongum
blunt-glumed panicgrass
long-stalk panic grass
15-50 cm, slender, wiry;
internodes olive green to purplish, densely puberulent or glabrous;
fall phase spreading or decumbent, branching extensively from the lower and midculm nodes, producing numerous congested fascicles of reduced, flat or involute blades and reduced secondary panicles.
10-50 cm, erect, lower 3-6 internodes telescoped together, forming a slender 2-4 cm column, upper 2 internodes elongated;
nodes bearded;
internodes puberulent and pubescent;
fall phase with sterile branches arising near ground level and foreshortened reproductive branches arising from the higher nodes, secondary panicles small and narrow, enclosed within the sheaths, with 5-10 spikelets.
4-7;
sheaths much shorter than the internodes, densely crisp-puberulent, velvety-puberulent, or glabrous, often ciliate along the margins;
ligules shorter than 0.5 mm;
blades 2-7 cm long (seldom longer), 2.5-8 mm wide (rarely wider), spreading, firm, flat or slightly involute, without prominently raised veins, not longitudinally wrinkled, densely puberulent or glabrous abaxially, glabrous, sparsely puberulent, or pubescent adaxially, bases subcordate, with papillose-based cilia, margins often whitish and scabridulous.
2-4;
sheaths longer than the internodes, pilose;
ligules about 0.5 mm;
blades 5-20 cm long, 1-3.5 mm wide, stiffly erect, long-tapering, sometimes involute, green or grayish-green, pubescent to pilose, upper 2 or 3 blades much longer than those below.
1.5-2.6 mm, obovoid-pyriform, planoconvex in side view, puberulent, pubescent, or glabrous, attenuate basally, apices usually broadly rounded.
2.6-3.4 mm long, 1-1.7 mm wide, ellipsoid-obovoid, turgid, finely pubescent.
0.6-1.4 mm, thin, weakly-veined, attached about 0.2 mm below the upper glumes, clasping at the base;
upper glumes as long as or slightly shorter than the lower lemmas;
upper florets 1.4-2 mm, broadly ellipsoid, apices subacute, minutely puberulent.
1-1.4 mm, broadly ovate;
upper glumes and lower lemmas exceeding the upper florets by 0.2-0.3 mm before flowering, slightly pointed at maturity, upper florets obovoid, 1.9-2.7 mm, minutely umbonate.
rosettes well-differentiated;
blades 1.5-6 cm, ovate to lanceolate.
rosettes poorly developed;
sheaths 2-4 cm;
blades similar in shape to the lower cauline blades, narrow, ascending.
panicles 2-7 cm long, 2/3 to nearly as wide as long, with relatively few spikelets, exserted;
branches flexuous, spreading or reflexed, scabridulous to densely puberulent.
panicles 3-8 cm long, 1-3 cm wide, narrowly ellipsoid, long-exserted, with 12-25 spikelets;
branches ascending;
pedicels 2-4 mm, appressed.
= 18.
= 18.
Dichanthelium portoricense
Dichanthelium perlongum
Dichanthelium portoricense grows in sandy woods, low pinelands, savannahs, and coastal sand dunes, usually in moist places. Its range extends south from the Flora region into Mexico, the Caribbean, and Mesoamerica. It is a highly variable species with numerous intergrading forms, some possibly resulting from hybridization with other widespread species in the same region, such as D. sphaerocarpon and D. commutatum.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Dichanthelium perlongum grows in dry to mesic prairies, and is restricted to the Flora region. It appears to hybridize occasionally with D. depauperatum and D. linearifolium. The primary panicles are briefly open-pollinated and develop from May to early June; the secondary panicles are cleistogamous and are produced from mid-June through mid-July.
Dichanthelium perlongum is similar to D. wilcoxianum, but differs in having only the upper 1 or 2 blades greatly elongated (usually more than 20 times longer than wide), narrow, erect basal blades, and a contracted panicle with ascending branches. Dichanthelium acuminatum also may also be confused with D. perlongum only if its upper internodes elongate, as tends to be the case after a spring fire, but D. acuminatum has less turgid spikelets and hairs in the ligule area that are 3-5 mm long.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Spikelets 1.8-2.6 mm long, usually densely pubescent or puberulent (rarely glabrous); cauline blades 4-7 cm long, 3.5-8 mm wide | subsp. patulum |
1. Spikelets 1.5-2.0 mm long, puberulent to nearly glabrous; cauline blades 2-5 cm long, 2.5-4.5 mm wide | subsp. portoricense |
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