CONCERNING ' 



1 pa: 



93 



202 308 804 



Fig. 802. A seed of the Cotton-plant, with it^ tnft of coma, or cotton. 



Fig. 803. A seed of the Cotton-tree {Populus), with its silky coma. 



Fig. 804. A winged seed of the Catalpa. 



Fi^. 805. Achenium of Eolipta; it has no pappus. 



Fig. 806. Acheninra of Horseweed; scarcely any pappus. 



Fig. SOT. Achenium of Sunflower; has two awns for pappus. 



Fig. 308. Achenium of Ageratnm ; has five sepals for pappus. 



Fig. 309. Achenium of Bluo Milkweed; has abundant pappus. 



Fig. 810. ' Achenium of Wild Lettuce ; with 'pappus raised on a beak. 



188. The learner must distinguish between the coma of a 

 seed and the pappus of a fruit. Tlie down of Thistle or Dan- 

 delion is pappus, for the little fruit on which it grows is not 

 merely a seed, but a pericai-p (achenium), also containing one 

 seed. In a word, the seed may be fledged with a coma, but 

 the fruii is fledged with a pappus, both intended as wings 

 to bear away the seed to distant p'laces. (See Class Book of 

 Botany, §485.) 



188. What is the distinction between "coma and pappus? 



