220 



THE FLORA. 



ant, when all the florets are ligulate (Fig. 504) ; discoid, when all the florets 

 are tubular, there being no rays (Fig. 509). The receptacle is the broad 

 top of the stalk on which the florets sit (Fig; 499). It is cTiaffy when there 

 are scales or bracts growing among the florets, and naked when none. 



The tubular florets constitute the di^lc, and the ligulate, if any, the ray ; 

 the disk is generally yellow, while the ray is about as often cyanic (that is, 

 blue, red, white, or' any color except yellow) as yellow. 



Fig 498. A Sunflower, — head radiate. 9. Vertical secition of the head, showing the scales of 

 the inTOlucre, and a single disk-flower remaining upon the convex receptacle. Fig. 500. A per- 

 fect disk-flower magnified, showing the acheninm, the 2 awns of the pappus, the 5-toothed tn-^ 

 bular corolla, the 5 stamens united around the branched style, and the chaff-scale at hose. 1. Head 

 (radiate) of Solidago cfesia. 2. A pistillate, ligulate flower of the ray. 3. A perfecUdisk-flower. 

 4 A (radiant) head of Dandelion. 5. A perfect, ligulate flower. 6. Acheninm, with ite long 

 beak and feathery pappus. 7. A (radiant) head of Nahalua altissimus. 8. A flower. 9. Lappa 

 (Burd ck), head discoid, 10. A flower. 11. One of the hooked scales. 12. A (discoid) head of 

 Eupatorium purpureum. 13. A flower. 14. .4m5rosia (Pigweed). 15. Stamiuate head enlarged. 

 16. PistiUato involucre enlarged. IT. The fertile flower. 



