Bur GrassCenchrus carolinianus Walt.
Nature has decreed that the gatherers of her harvests shall be disseminators of the plants they use. But those weeds which are tramps of the wayside, like Spanish needles, burdock, and Burgrass, having nothing of value to commend their transportation to new fields, have developed an insistent scheme for pushing new generations out into the world, and bind burdens upon all passersby.
Most appropriately do botanists comment upon Bur-grass as "a vile and annoying weed," since it is one that causes trouble from the Atlantic to the Pacific. No one who has walked along railways, to find them Elysian fields in their variety of flora, can forget climbing sandy embankments through a hindering growth of this plant.
Bur-grass is more abundant in the Southern than in the Northern states. It is low and spreading, sometimes carpeting the ground on waste land and near sandy shores, and the flowering spikes, composed of numerous, spiny burs, present a peculiar appearance, leading one to doubt if this can be grass at all.
A reddish tinge is often noticeable in the flat sheaths as well as in the stems, and in the burs, which are really involucres enclosing the spikelets. Before the blossoming-head breaks from the sheath each involucre is short and cup-like, surmounted by broad green bristles, but at maturity these bristles are grown together into a hard bur which encloses the seeds and is beset with spines of needle-like sharpness.
Later in the season the burs readily become detached and, adhering to passing objects, are carried long distances until they fall on new soil where the seeds establish new colonies of this troublesome grass.
Bur-grass. Sand-grass. Devil-burs. Hedgehog-grass. Cenchrus carolinianus Walt.
Stem 6'-24' in length, much branched, erect or spreading. Sheaths loose, smooth, flattened. Ligule a ring of short hairs. Leaves 2'-6' long, 2"-4" wide.
Spike 1'-3' long, composed of 6-20 round, spiny burs enclosing the spikelets; burs more or less downy, sometimes reddish; spines very rigid at maturity. Spikelets 2-flowered, about 3" long. Scales 4, thin. Stamens 3.
Sandy soil. July to September.
Maine and Ontario to South Dakota, south to Florida, Texas, and southern California.