LXXV. COMPOSITiE. 



311 



The Jtmoera are moreover said to be 



Cftne disk, where they stand in or near the centre of the head; 



Of (fie rail. \\\\vu \\\v\ stand in the outer rircic or rjrcnmflTence of the head; 



LiiTulati' (straii-.shap(<l), w hen the ImiiIj is spht on one side and Hjiread open in the form of a Strap. 



Tubular, wIrii tlicy an- nioiiuinialoiis uitli a rejjular limb. The licads are termed 



lJimviL^uiiU)Us, wlicrc they con.si.sl wholly orpcrlin-l llowerH; 



llitcros-ciitMus, where the flowers of the disk are perlect or staminute, while those of the ray or margin 

 are pistillate or neutral : 



Kudidiit, where the tlowers are all lipulale, as in the dandelion ; 



Radiate, where tiiose of tlie ray or mart'ln only arc Ululate, the rest being tubular, as in Aster; 



Discoid, where all the llouers are luliuhir, a;i in the t/iurouir'twirl : 



Moncrciuu-s, where the same head has l.otli stamniate aixi 'pistillate flowers; 



Hi-teroivpiw.liiu-'i. where the same individual i)laiit has some of its heads wholly of slaminate. and othera 

 wholly of pistillate flowers. 



Did nous, where tlie same species has some of its individuals with stnminate heads only, and others 

 M-ith pistillaie lieads only. The anthers are usually appendiculate, that is, prolonged at the summit into 

 a membranous appendage. The achenia are termed 



Rostrate, when they are prolonged at the summit into a slender neck supporting the pappus, as in the 

 dandelion ; 



Cmnpre^ed, when they are flattened parallel with the diameter of the head ; 



Obcompressed, when flattened parallel with the circumference of the head. 



FIG. 47.— 1. Helianthus strumosus— head radiate. 2. Vertical section of the head, showing the scales 

 of the involucre, and a single disk-flower remaining upon the convex receptacle. 3. A perfect disk-flower 

 magnified, showing the achenium. the 2 awns of the pappu.s, the 5-tootheil tubular corolla, the 5 stamens 

 united around the branched style, and the chaft'-scale at base. 4. Head (radiate) of ^olidago CiBsia. 

 5. A pistillate, ligulate flower of the ray. 6. A perfect di.'sk fl. 7. A (radiant) head of Taraxacum Dens- 

 leonis. 8. A perfect, li^'ulate fl. 9. Achenium, with it.s lonjj beak and plumose pappus, lo. A (radiant) 

 head of Nabalus altissimus. 11. A flower. _ 12. Lappa major, head discoid. 13. A flower. U. One of 

 the hooked scales. 15. A (discoid) head of Eupatorium purimreuni. 16. A flower. 17. Ambrosia arte- 

 misiafblia. 18. Staminate head enlarged. 19. Pistillate involucre eidarged. 20. The fertile flower. 



Conspectus of tlie Genera. 



\ Leaves alternate. . . . § I 

 < Corollas cj'anic. ( Leaves opposite or verticillate. § 2 



f discoid. I Corolks yellow § 3 



< Leaves alternate. . . . § 4 



i Rays yellow. . \ Leaves opposite or all radical. § 5 



< ^ Leaves opposite or all radical. § 6 



, radiate. ( Rays cyanic. . I Leaves alternate. . . . § 7 



Heads (.radiant § 8 



27 



