THE FRUITS OP WEEDS. 41 



raceme, the lower peduncles being lengthened to raise their flowers 

 or heads to the same level as those above, as in yarrow; a cyme 

 which is only a corymb with all the blossoms from terminal buds, 

 the one on the main stem opening first, followed by those on the 

 side shoots, as in chickweed ; an umbel, as in milkweed and wild 

 onion, where all the flower-stalks seem to arise from a single point 

 like the ribs of an umbrella, whence the name. 



Compound flower clusters of each of the above kinds are fre- 

 quent, as the compound umbel of the wild carrot where the stalks 

 of the first or lower umbel become themselves umbels and bear um- 

 bellets. A compound raceme which branches loosely and irregu- 

 larly is called a panicle and is seen in oats and most grasses. A 

 head, umbel or other flower cluster is often surrounded by a whorl 

 or circle of bracts or small leaves called an involucre. These are 

 present in the thistle and other Composite as well as in sedges and 

 many other weeds. 



THE FRUITS OF WEEDS. In botany the word fruit is used to 

 designate the mature or ripened ovary or seed vessel with the en- 

 closed seeds, whatever its nature and whether it is edible or not. 

 It also includes any appendages of the flower which are perma- 

 nently attached to it, such as the calyx of an apple or the fleshy 

 receptacle at the center of a blackberry. Tlie fruits of weeds, like 

 those of other plants, are therefore exceedingly variable in struc- 

 ture and form. 



In general, fruits are either fleshy or dry. Not very many 

 weeds have fleshy fruits. However the drupe or stone-fruit, hav- 

 ing the outer part fleshy and the inner part hard and stony and 

 enclosing the seed, is represented in the blackberry, where the little 

 drupes are massed together around the fleshy receptacle, and also 

 in the fruit of the poison ivy. The berry is another form of fleshy 

 fruit in which the hard coated seeds are enclosed in and directly 

 surrounded by the fleshy pulp. The fruits of pokeweed, horse 

 nettle, ground cherry, etc., are therefore true berries. When eaten 

 by birds and other animals the hard seeds of both drupes and ber- 

 ries are not digested but are passed with the excrement and thus 

 gain wide dispersal. 



Dry fruits are of two kinds, viz., the indehiscent which do not 

 open at maturity and the dehiscent which split open, usually along 

 regular lines, and scatter the seeds. Of the numerous kintfs of 

 indehiscent fruits but three are commonly met with among weeds. 

 The achene is a small dry one-seeded indehiscent fruit often so 

 seed-like in appearance that it is taken for a naked seed. However 



