Plants stoloniferous, usually also rhizomatous. Culms
5-40(50) cm, not becoming woody. Sheaths glabrous or with scattered hairs;
collars usually with long hairs, particularly at the margins; ligules
about 0.5 mm, of hairs; blades 1-6(16) cm long, (1)2-4(5) mm wide, flat
at maturity, conduplicate or convolute in bud, glabrous or the adaxial surfaces
pilose. Panicles with (2)4-6(9) branches; branches 2-6 cm, in
a single whorl, axes triquetrous. Spikelets 2-3.2 mm. Lower glumes
1.5-2 mm; upper glumes 1.4-2.3 mm; lemmas 1.9-3.1 mm, keels not
winged, pubescent, margins usually less densely pubescent; anthers dehiscent
at maturity; paleas glabrous. 2n = 18, 36.
Cynodon dactylon is a variable species, but taxonomists disagree on just
how variable. Caro and Sánchez (1969) limited C. dactylon to plants
with conduplicate leaves, placing those with convolute leaves in a number of
other species, such as C. affinis Caro & Sánchez and C. aristiglumis
Caro & Sánchez; de Wet and Harlan (1970) do not mention this character
in their study of Cynodon. Caro and Sánchez also employed several
other characters in the key separating C. dactylon from the species with
convolute immature leaves, but the overlap between the two sides of the lead
is substantial. Pending further study, the broader interpretation, in which
C. dactylon includes plants with both convolute and conduplicate leaves,
has been adopted.
Several varieties of C. dactylon have been described,
in addition to which numerous cultivars have been developed, some as turf grasses
for lawns or putting greens, others as pasture or forage grasses. Their useful
range is limited because C. dactylon is not cold hardy, going dormant
and turning brown when nighttime temperatures fall below freezing or average
daytime temperatures are below 10° C.
The most commonly encountered variety, both in the Flora
region and in other parts of the world, is C.
dactylon var. dactylon, largely because it thrives in severely
disturbed, exposed sites; it does not invade natural grasslands or forests.
Determining how many other varieties are established in the Flora region
is almost impossible, because there has been no global study of variation in
the species. The presence of numerous cultivars complicates an already difficult
problem. The two varieties keyed out below are the only two that grow in the
Flora region according to de Wet and Harlan (1970), but these authors
do not appear to have considered the taxa recognized by Caro and Sánchez
(1969). For most purposes, it is probably neither necessary nor feasible to
identify the variety of C. dactylon encountered.
Cynodon dactylon is considered a weed in many countries
and it is true that, once established, it is difficult to eradicate. It does,
however, have some redeeming values. It is rich in vitamin C, and its leaves
are sometimes used for an herbal tea. It is claimed to have various medicinal
properties, but these have not been verified. It is considered a good pasture
grass, in addition to which it is sometimes grown as an ornamental and for erosion
control on exposed soils.
Dr. David Bogler, USDA NRCS PLANTS Database
Perennials, Terrestrial, not aquatic, Rhizomes present, Rhizome elongate, creeping, stems distant, Stolons or runners present, Stems trailing, spreading or prostrate, Stems nodes swollen or brittle, Stems geniculate, decumbent, or lax, sometimes rooting at nodes, Stems mat or turf forming, Stems terete, round in cross section, or polygonal, Stem nodes bearded or hairy, Stem internodes hollow, Stems with infloresce nce less than 1 m tall, Stems, culms, or scapes exceeding basal leaves, Leaves mostly cauline, Leaves conspicuously 2-ranked, distichous, Leaves sheathing at base, Leaf sheath mostly open, or loose, Leaf sheath smooth, glabrous, Leaf sheath hairy, hispid or prickly, Leaf sheath and blade differentiated, Leaf blades linear, Leaf blades 2-10 mm wide, Leaf blades mostly flat, Leaf blade margins folded, involute, or conduplicate, Leaf blades mostly glabrous, Leaf blades more or less hairy, Ligule present, Ligule a fringe of hairs, Inflorescence terminal, Inflorescence solitary, with 1 spike, fascicle, glomerule, head, or cluster per stem or culm, Inflorescence a panicle with narrowly racemose or spicate branches, Inflorescence a panicle with digitately arranged spicate branches, Inflorescence with 2-10 branches, Inflorescence branches 1-sided, Lower panicle branches whorled, Inflorescence branches paired or digitate at a single node, Rachis dilated, flat, central axis to which spikelets are attached, Rachis angular, Flowers bisexual, Spikelets sessile or subsessile, Spikelets laterally compressed, Spikelet less than 3 mm wide, Spikelets with 1 fertile floret, Spikelets solitary at rachis nodes, Spikelets all alike and fertille, Spikelets bisexual, Spikelets disarticulating above the glumes, glumes persistent, Spikelets secund, in rows on one side of rachis, Rachilla or pedicel glabrous, Glumes present, empty bracts, Glumes 2 clearly present, Glumes equal or subequal, Glumes distinctly unequal, Glumes shorter than adjacent lemma, Glumes keeled or winged, Glumes 1 nerved, Lemma coriaceous, firmer or thicker in texture than the glumes, Lemma 3 nerved, Lemma body or surface hairy, Lemma apex acute or acuminate, Lemma awnless, Lemma margins thin, lying flat, Lemma straight, Palea present, well developed, Palea membranous, hyaline, Palea about equal to lemma, Palea 2 nerved or 2 keeled, Stamens 3, Styles 2-fid, deeply 2-branched, Stigmas 2, Fruit - cary opsis.
Widely spreading by stolons and rhizomes and forming mats, the culms erect or ascending, 1-3 dm; main lvs 2-4 mm wide; spikes 4-6, divergent, 3-5(-8) cm; glumes 1.5-2.2 mm, the first curved, the second nearly straight; lemma 2-2.5 mm, minutely pubescent to long-villous on the keel; 2n=36, 40. Native of the Old World, abundant (and often cult.) in lawns and in disturbed sites in s. U.S. (n. to Del.) and adventive n. to N. Engl., Mich., and Nebr. (Capriola d.)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.