222 



BOTANY. 



squashes, etc. They are climbing or running plants, and pro- 

 vided with tendrils. The flowers are usually unisexual, some- 

 times dioecious, but oftener monoecious (Fig. 123, /). 



The last and highest order of the Sympetalce, and hence of 



FIG. 125. Anisocarpous sympetalse (Aggregate). Types of Composite. A, 

 inflorescence of Canada thistle (Cirsium), x 1. B, vertical section of A. r, 

 the receptacle or enlarged end of the stem, to which the separate flowers are 

 attached. (7, a single flower, x 2. o, the ovary, p, the ''pappus" (calyx 

 lobes), an. the united anthers. D, the upper part of the stamens and pistil, 

 x 3 : i, from a young flower ; n, from an older one. an. anthers, yy. pistil. 

 E, ripe fruit, x 1. F, inflorescence of may-weed (Marutu). The centra} 

 part (disc) is occupied by perfect tubular flowers (G), the flowers about the 

 edge (rays) are sterile, with the corolla much enlarged and white, x 2. Q, 

 a single flower from the disc, x 3. H, inflorescence of dandelion ( Taraxa- 

 cum), the flowers all alike, with strap-shaped corollas, x 1. /, a single 

 flower, x 2. c, the split, strap-shaped corolla. 7, two ripe fruits, still 

 attached to the receptacle (r). The pappus is raised on a long stalk, x 1. 

 K, a single fruit, x 2. 



the dicotyledons, is known as Aggregatce, from the tendency 

 to have the flowers densely crowded into a head, which not 

 infrequently is closely surrounded by bracts so that the whole 

 inflorescence resembles a single flower. There are six families, 



