deertongue grass
Dichanthelium clandestinum (L.) Gould

click thumbnail to see a larger image


Deertongue grass is rare in Iowa, occurring primarily in the southeastern corner of the state in semi-open areas in damp or sandy woodlands or on brushy roadsides. This species is widely distributed in the eastern United States, reaching Kansas, Oklahoma and east Texas, although it is uncommon in the southeastern Coastal Plain. Like other species of Dichanthelium, deertongue grass is characterized by two distinct blooming periods. The conspicuous primary flowering heads are terminal to the culms and are produced from late May into early July. Usually from July through September, the plants branch to produce small secondary flowering heads that remain mostly concealed within the sheaths. The primary flowering heads usually have a lower seed set than the secondary ones, which have flowers that remain closed and are self-pollinated. In winter, the sheaths may be shredded by chickadees that split the sheaths and eat the plump grains hidden within (Clark & Pohl, 1996).

Deertongue grass is characterized by its hispid (having stiff hairs) secondary branch sheaths, smooth leaf blades, and concealed axillary flowering heads. The hairs on the sheaths usually have distinctive warty bases that persist even when the hairs have fallen off. This species is most similar to broadleaved panicgrass (Dichanthelium latifolium), but the two are easily distinguished because broadleaved panicgrass has usually smooth sheaths (or if they are hairy, the hairs lack warty bases) and hairy leaf blades. And as the name implies, its leaf blades are very broad (13-40 mm wide as opposed to 8-28 mm in deertongue grass). 

Etymology: Dichanthelium from the Greek di = twice and anth = flowering, referring to the occurrence of two distinct flowering periods; clandestinum from the Latin clandestinus = hidden, a reference to the small secondary flowering heads concealed in the leaf axils.


Plants perennial, forming large tufts from short rhizomes. Culms 40-120 cm, stout; nodes not swollen, smooth or sparsely hairy; internodes papillose-hairy to nearly smooth. Fall phase with a few, nearly erect, elongate branches, sparsely rebranching, the sheaths overlapping, concealing the secondary panicles. Basal rosettes well differentiated.  Leaves along the culms with sheaths not overlapping, ribbed, with warty-based hairs; blades 4-23 cm long, 8-28 mm wide, relatively broad, often stiff, usually smooth, sometimes with sparse hairs, the bases heart-shaped. Primary flowering heads terminal, borne above the leaves, 9-13 cm long, 4-7 cm wide, pyramid-shaped in outline. Spikelets 2.9-3.2 mm long, 1.2-1.4 mm wide, narrowly ellipsoid, sparsely hairy; lower glumes 1.1-1.4 mm long, 1/3-1/2 as long as the spikelets, narrowly triangular; upper florets slightly exceeding the lower lemmas, with a minute tuft of hairs at the apices. Chromosome number 2n = 36.


home - common name index - scientific name index - database - picture key - weedy grasses - ornamental grasses - Ada Hayden Herbarium - ISU