CHAPTER X 



California, Trifolium tridentatum, Lindl., and T. involucratum, 

 Willd., are rather common in loamy soil ; the former, found in dryer 

 soil, has narrow, acute leaflets and small heads of purple and white 

 flowers ; the latter, found where there is more moisture, has more 

 luxuriant foliage, and flower clusters that resemble the cultivated T. 

 pratense, L., of the North Atlantic States. These species, however, 

 vary extremely in different localities, and are sometimes difficult to 

 distinguish from each other and from kindred species. They have 

 abundant honey, exclude short-tongued guests, and seem able to pol- 

 linate themselves, but whether they are fertile to their own pollen I 

 do not know. Some of the most valuable cultivated clovers will not 

 produce seed without cross fertilization, and as our Kastern farmers 

 clear away the forests that harbor the bumble-bees, they have to 

 import clover seed. Australian farmers have imported the bees with 

 the clover. Our so-called wild peas and vetches come under two 

 genera, Lathyrus and Vicia. The Lattiyrus of Southern California is 

 a vigorous climber that blooms often as early as January, and con- 

 tinues in bloom all spring. The flowers are so variable that it is diffi- 

 cult to decide whether there are several species or several varieties of 

 one species (vestitus) ; most commonly they are white or cream color 

 with veins of violet or rose, but they are often entirely rose-colored, 

 violet or nearly purple, and one sort has exceedingly handsome crim- 

 son flowers. The flowers of Vicia Americana, var. truncata. Brewer, 

 are often confused with the others ; they are more slender, and per- 

 haps more bluish in color, but a sure way to distinguish them is by 

 the style ; in both genera there is a brush of hairs just below the 

 stigma or tip of the style ; in the Vicias this brush extends around the 

 style, in the Lathyrus it is on the inner surface only. In both genera 

 this tiny brush serves an important end. The anthers shed their pol- 

 len early into the keel and over the brush and stigma, which, how- 

 ever, is not yet mature. The wings and keel are firmly united by 

 means of pouch and socket, as in the alfalfa ; and, as in alfalfa, the 

 honey is accessible through two openings at the base of the upper, or 

 free stamen. At the base of the flower the banner fits closely over the 

 rest, and only strong insects can force an entrance to the honey ; hive 

 bees can, with considerable scrambling, succeed with the Vicia, but 

 not with the Lathyrus ; but the larger native bees, particularly bumble- 

 bees, are frequent guests with both species. As the lower part of the 

 flower is forced down, the style brush sweeps out some pollen against 

 the insect's body, and the friction of the guest against the stigma is 

 said to render it receptive to the foreign pollen the insect brings ; 

 such is the elasticity of the tissue involved, that tfie stamens and style 



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