88 NOMENCLATURE OF THE FLOWER. 



52. Tunic : The tunic or arillus, is cither a com- 

 plete or partial covering of a seed, fixed to its base only, 

 and more or less loosely or closely enveloping its other 

 parts. 



The mace which envelopes the nutmeg is a partial arillus. In the 

 oxalis or wood-sorrel, there is an elastic pouch-like arillus, serving 

 to project the seeds with considerable force. 



53. Seed-down : The pappus or seed-down, is a sort 

 of feathery or hairy crown, with which many seeds, 

 especially those of the compound flowers, are furnished, 

 evidently intended for the dispersion of the seed to a 

 considerable distance. 



Instances of the pappus are the feathery appendages to tlie seeds 

 of dandelion and goafs-heard, in which it is elevated on a foot-stalk 

 The seeds of the groundsel, hawkweed, and the thistle, are also 

 furnished with this kind of down. 



54. Tail : The cauda or tail, is an elongated (gene- 

 rally feathery) appendage to some seeds, formed from 

 the permanent style. 



The seeds of virgins bower, and pasque flower, may be selected 

 for illustrations of the cauda. 



55. Beak: The rostrum or beak is usually applied 

 to some elongation of a seed-vessel, originating likewise 

 from the permanent style. 



The seeds of geranium, hellebore, stone crop, and others, are 

 furnished with this species of appendage. 



56. Wing .-The ala or wing, is a dilated membra- 

 neous appendage to some seeds, serving to waft them 

 along in the air. 



