270 



EECEEATIVE SCIENCE. 



fertilization upon the stamens of the disk, as 

 Trell they may. 



UTow, this colt's-foot blossom is a most 

 excellent example of this tribe of plants, the 

 Composites, which for all their appearance be- 

 lied them. Here you see one-pieced blossoms 

 after all, only the blossoms are collected into 

 a close bead or capitulum, instead of being 

 spread over a stem or peduncle. The part 

 on which the florets are placed (Figs. 49, h, 

 and 50, h), and which represents the peduncle, 

 is called in these plants the receptacle ; and 

 the green envelope which represents the 

 leaves of the peduncle, or hracts, is called 

 the involucre (Figs. 49, h, and 51, h). 



You must not run away with the idea, 

 however, that all our composite heads of 

 flowers are exactly similar to the colt's-foot. 

 In the daisy, in the ragwort (Fig. 44), in 

 the wild chamomile (Fig. 43), you will find 



Fiff. 50. — Section of Head, or Capitnlum, of Common 

 Thistle, a, florets; 6, common receptacle; c, bracts, 

 or involucre. 



them similar ; but not so in the hawkweed 

 (Fig. 51) or in the dandelion, which should 

 not have waited our special mention until 

 now. In the latter, the florets are all strap- 

 shaped, like those of the colt's-foot ray ; whilst 

 m the thistle (Fig. 50), and other allied com- 

 posites, they are all tubular, like those of the 

 colt's-foot disk. 



It will be an excellent lesson and exercise 

 for you to gather these composite blossoms 

 and examine them. You must expect, in 

 doing so, .to find considerable variation in 

 the distribution of the stamens and pistils in 

 the tiny florets. The composites form such 

 an extensive family, that botanists are fain 

 to divide them, according to these floret disr 

 tinctions, into tribes, whereof the lettuces, 

 dandelion, hawkweed, etc., belong to one, 

 the thistles and burdocks to another, the 

 daisy, ragwort, colt's-foot, and many another 

 to the third. 



Fig. 61. — Back View of Blossom of Common Hawk- 

 weed. a, strap-shaped florets of ray ; 6, bracts, 

 constituting the common involucre ; c, peduncle ; 



d, scale. 



We have already alluded to the peculiar 

 form which the calyx — not the involucre, 

 remember — assumes in the composite family ; 

 feathery in a greater or less degree, as fami- 

 liar to us all in thistle-down, and in the dan- 

 delion parachute, and botanically called the 

 pappus. It remains after the floret has 

 withered and fallen ofi", and untU the ripened 

 seed calls for its aid to transport it far from 

 the parent plant. Something more of this 

 aerial seed-sowing shall we learn when we 

 come to examine our fruit-basket. It is not 

 all composites, however, which have these 



