204 



ANTHOTAXY 



combined tori of all the flowers of the anthodium, is called a Receptacle 

 (6). It is to be studied as to its being solid or hollow; as to its general 

 form, and especially the form of its upper surface, whether concave, 

 plane, convex, rounded, or conical; as to its being smooth in surface, 

 honeycombed or otherwise pitted (foveolate), and if the latter, the 

 special characters of the pits and their margins; and as to its being naked 

 or clothed with hairs or scales, and the characters of the latter in their 

 every detail. The head is then to be considered as to the character of 

 its flowers. If these are all sexually similar, the head is said to be 

 Homogamous; if different, Heterogamous. If the flowers are aU Ugu- 

 late, the head is Liguliflorate. If it possess a disk (c), of tubular flowers 

 id), it is Discoid. If this disk is surrounded by one or more circles of 



Fig. 587. Vertical section through an anthodium: a, involucre; 6, receptacle; c, disk; d, disk- 

 flower; e, ray-flower. 



ligulate flowers called Rays (e), it is Radiate. If the ray-flowers and 

 disk-flowers are of the same color, the head is Homochromous; if 

 different, Heterochromous. The flowers must next be studied as to 

 their sex. The ray-flowers are commonly pistillate, while the disk- 

 flowers are perfect, or the disk-flowers may vary among themselves in 

 this particular. Very commonly, the ray-flowers are entirely neutral. 

 Even if pistillate, they may be sterile. If both classes of flowers are 

 fertile, the akenes which they produce may be heteromorphous, those 

 of the disk being commonly compressed, those of the rays commonly 

 triquetrous. Occasionally the heads are dioecious or monoecious. In 

 one tribe of the Compositae the coroflas are bilabiate. The character 

 of the pappus (Figs. 7-4 to S3) is invariably of the utmost importance, 



