CONCERNING THE PAPPUS. 



9:^. 



302 303 



Fig. 302. A seed of the Cotton-plant, with its tuft of coma, or cotton. 



Fig. 303. A seed of the Cotton-tree {Populus), with its silky coma. 



Fig. 804. A winged seed of the Catalpa. 



Fig. 305. Aehenium of Eclipta; it has no pappus. 



Fig. 306. Aehenium of Horseweed ; scarcely any pappus. 



Fig. 307.' Aehenium of Sunflower; has two awns for pappus. 



Fig. 308. Aehenium of Ageratum ; has five sepals for pappus. 



Fig. 309. Aehenium of Blue Milkweed; has abundant pappus. 



Fig. 310. Aehenium of "Wild Lettuoc ; witli i->appus raised on a beak 



188. The learner must distinguisli between tlie 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 pericarp (aehenium), also containing one 

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

 \\\e fruit is fledged with a pappus, both intended as wings 

 .0 bear away the seed to distajit places. (See Class Book of 

 Dotany, § 485.) 



188. Wliat is the distinction bct'.veen coma iind paijnis? 



