Literature.
Thomas Shaw, " Clovers and How to Grow Them," 1905; chapters and ref erences in various crop books, as the books on forage crops by Hunt, Voorhees and others ; Group II. Less important or weed clovers.
The small, introduced clovers of this group, occurring about culti vated lands or along roadsides, are of two kinds,— the yellow-flowered and the silky-headed. They are all low, more or less trailing or weak-spreading annual plants, producing little herbage and of small value where other clovers will succeed. One of the black medics (1fedicago lupulina, the bur or hop clover) is often confused with the true clovers.
The commonest yellow-headed clovers are Tri folium agrarium, Linn., sometimes called yellow or hop clover (Fig. 339), with ovate-oblong leaflets that are all sessile and narrow stipules atf ached prominently to the petiole, the plant about a foot high ; T. procumbens, Linn., the low or creep ing hop clover (Fig. 340), with wedge-shaped leaf fists, the terminal one of which is short-stalked, and short stipules, the heads smaller (one-half inch, or less, long), and the plant more spreading and about six inches tall. T. agrarium (sometimes called T. aureum) is very abundant on sandy lands in some parts of the country, and is considered to be of some value as pasture.
The other group comprises only one common species, the rabbit-foot or stone clover (T. aroenge, Linn.) (Fig. ?AI). The plant grows a foot high, silky-gray all over, the leaflets linear or oblanceo late, the whitish-flowered heads becoming silky and soft. This clover is often so abundant on light lands as to form the principal growth after scattered bulletins of Experiment Stations and the United States Department of Agri culture.
Red Clover Seed Growing.
The clover-seed crop of the United States, in 1900, was placed by the census of that year at 1,349,209 bushels. Over 85 per cent of the crop was produced in the group of states in cluding Indiana, Ohio, Illinois, Wisconsin and Michigan,—mentioned in the decreasing order of their importance. The yield varies from nothing to eight bushels per acre, the average being not far from two to three b ishels. Site bushels per acre is a good yield, and
tight bushels a large yield. The price for the past five yea N has varied from four to thirteen d?.11ars per hundred pounds. Good seed can seldom be bought for less than five dollars per bushel. Chicago, Cincinnati, Toledo and Detroit are the large market centers for this crop. The price is usually higher in Chicago than in the other cities m ntioned.
Color.
Fresh red clover seed of good quality has a bright plump appearance. The seeds vary in color from dark violet to yellow, with all intermediate shades. Sometimes green and brown or black seeds are found in greater or less abundance. The vio let and yellow seeds are produced in about equal abundance and are generally considered equally valuable for planting. The dark seeds are heaviest, followed by the variegated, and the average of these is still heavier than the lighter-colored seed. The predominating color of the seed sown usually predominates also in the resulting seed-crop. Euro pean investigations show a higher yield of leaf and stem from yellow than from violet seed.
Si:e.
In size, red clover seed varies from twelve mil lion to twenty-five million seeds per bushel, the average for American seed being sixteen to eigh teen million per bushel. M'Alpine points out, as a result of English experiments, that small seed may pro lace more forage than a like weight of large seed, because more plants are produced. The rank early growth produced by large seed sown with grain is of no importance, since a hay crop is not cut until the following year, when the weaker plants from small seed may compete in size with plants from large seed.
Grades.
Several grades of clover seed are usually on the market. The value of a sample of seed depends on its cleanness, the percentage and vigor of germi nation, size and origin. Generally speaking, north ern- grown seed is superior to southern seed. American seed gives much better results in the United States than European seed, which is some times imported.