Virginia Tech Weed Identification Guide

Deer-tongue Grass or Deer-tongue Panic Grass:

Panicum clandestinum or Dichanthelium clandestinum

Weed Description: A prostrate summer annual grass weed with leaves that resemble a "deer's tongue."  Primarily a weed of pastures and hayfields in the mountainous and piedmont areas of the southeastern United States.  This grass has traditionally been grouped in the genus Panicum but is now being classified by some as a Dichanthelium.
Leaves: Blades reaching 7 1/2 inches long, 12 to 25 mm wide, without hairs (glabrous) on either surface.  The bases of the leaf blades completely surround the sheath and are heart-shaped (cordate).  Hairs may also be present on the leaf bases.  Ligules reach 1 mm in length and are membranous but may occasionally also have a fringe of hairs (ciliate).  Leaves are rolled in the shoot. deertongue6-26b.jpg (11655 bytes)
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Stems: Reaching 4 inches in length, usually without hairs (glabrous) but nodes and internodes may occasionally have long, soft hairs.

Roots: A fibrous root system.

Flowers: A panicle that is typically 3 1/2 to 5 1/2 inches long and 2 1/2 to 3 1/2 inches broad.

Identifying Characteristics:  The wide leaves and prostrate growth habit of deer-tongue grass make it fairly easy to distinguish from most other grass weeds.  This weed may be confused with Jointhead Arthraxon (Arthraxon hispidus), but has a panicled seedhead unlike the spikelets of jointhead arthraxon.  The leaves of deer-tongue grass are generally much longer than those of jointhead arthraxon, and the stems of deer-tongue grass do not root at the nodes like those of jointhead arthraxon.   Deer-tongue grass may also be confused with Common or Asiatic Dayflower (Commelina communis), which also has broad grass-like leaves and a prostrate growth habit.  The two can be distinguished by the presence of a distinct ligule on deer-tongue grass, which is not present on common or asiatic dayflower.