104 



ACADEMIC BOTANY. 



Fio. 142.— a, 

 (Taraxacum Defis-Ieonjs) 



own proper calyx, -which is often pappose (Gr. 

 pappa, grandfather) ; that is, it has, instead of 

 sepals, long, silky hairs, called pappus, and 

 resembling an old man's heard ; as in the 

 Dandelion (Fig. 142), in which flie calyx, 

 after flowering, lengthens and ripens into a 

 long beak, which is tipped with the persistent 

 pappus. The composite receptacle, sometimes 

 Bat, sometimes cone-shaped, is also called a 

 disk (but it must be carefully distinguished 

 from the true disk of single flowers, as seen in 

 the Disciflorie). The bracts of the involucre 

 resemble sepals, but they are quite distinct 

 from sepals. In the Marigold (Pig. 143) the 

 central florets (florets of the disk, as they are 

 called) are tubular ; those at the circumference 

 are ligulate (strap-shaped) ; and because they 

 diverge like sun-rays, they are called ray-flo- 

 rets. In the Dandelion (Fig. 142) all the 

 florets are ligulate. In the Thistle, Edel- 

 weiss, and Artichoke (Fig. 214) all the florets 

 are tubular. 



224. In the Pea Order we find the Mimosa 

 (Fig. 130) and 

 the Clover (Fig. 

 132). In the Clo- 

 ver the r a oh is 

 often lengthens in 

 growing, so that 

 the head becomes 

 a spike. 



228. Taking the 

 raceme as a model, 

 the types are re- 

 duced on the one 

 hand through um- 

 £S'*t"2? bel and spike to 



!i,fr. 



Fig.. 143. —Section of Garden MarigoM 

 {CaXenAida, qfficinalis) : d, disk. 



head; and developed, on the other hand, Fig. 144.— Harebell (Campanula 

 into compound raceme, panicle, and ™ta<ii/b!ia) ; terminal flower with- 

 thyrsus. 



226. Definite Inflorescence (Cymose). Here the flower 



