193 



of the genera. In many genera there may be seen growing among 

 the flowers, and upon the receptacle, scales, which assume 

 various forms, sizes, and textures, and on the contrary are want- 

 ing in others. Some receptacles are large, some extremely 

 small. To the unhiitiated, ahead, or capitulum, often gives the 

 impression of being a single flower, (as has been shewn,) while 

 it really may contain dozens of flowers. Examine a Sunflower, 

 or Chrysanthemum, dissect them, look at each carefully, and 

 then see for yourselves whether they bo one flower, or, an 

 aggregation of many. Reverting to the presence or non-presence, 

 of scales upon the receptable, w^e will examine a few plants for 

 the purpose of illustrating the differences assumed in their form 

 and texture in difi'ei'ent genera. In Tridax, as represented by 

 T. procumbens, L., a common weed at the Botanic Gardens, the 

 scales are of rather a firm chaffy nature : in Wulffia stenoglossa, 

 D.jU., ortheSuniiower (Helianthusannuus. L.,) they are decidedly 

 stiff and firm, whilst in Dahlia they are found to be the contrary, 

 being quite soft, which also characterizes the genera. Zinnia, 

 Wedelia, &c. Emilia, Erechthites, Senecio, Leria, and Sonchus 

 are examples of naked receptacles. 



The receptacle may be either flat as in Brickellia, or 

 conical as in Zinnia. The meaning of syngenesious, as applied 

 to the stamens, require no further explanation as that has 

 ilready been noticed. 



As to the stamens, or male organs, they are seen to number 

 five, and because they are attached to the inside of the 

 monopetalous corolla tube, the term epipetalous is applied to 

 their position which consequently places all Composite plants in 

 the gamopetalous division of Dicotyledons. If Ave take some 

 orders, for instance, Malvaceae instead of the stamens uniting 

 together by their anthers, as in the Composita;, they are seen to 

 be xmited by their filaments, with the anthers free. Such an 

 arrangement as this is called monadelphous. Now, what is meant 

 by a one-seeded achene previously alluded to as being one of the 

 chief characters of the Compositaj ? An achene is the fruit of 

 this order and contains but one solitary seed, the latter only 

 being able escape from its chafp-like external covering after 

 decay has set in. In this and similar fruits where the covering 

 does not split open and allow the seeds to escape before becom- 

 ing decayed the term indehiscent is used ; in others as in 

 Malvaceous plants whei'e the capsules, or covering, split open as 

 soon as the seeds are matured, they are designated as being 

 dehiscent fruits. The calyx of the Composita; assume in many 

 genera a ring of hairs knoAvn as the pappus by which means the 

 fruits are blown from one district to another as in the 

 Dandelion, or, of awns, as in Bidens when they are 



