ON FRUITS AND SEEDS. 



361 



Another interesting geiius, again of the same family, is Myzoden- 

 dron (Fig. 16), a Fuegian species, described by Sir Joseph Hooker, 

 and parasitic on the beech. Here the seed is not sticky, but is provided 

 with four flattened, flexible appendages. These catch the wind, and 

 thus carry the seed from one tree to another. As soon, however, as 

 they touch any little bough, the arms twist round it and there anchor 

 the seed. 



In many epiphytes the seeds are extremely numerous and minute. 

 Their great numbers increase the chance that the wind may waft some 

 of them to the trees on which they grow ; and as they are then fully 

 supplied with nourishment they do not require to carry any store with 

 th^m. Moreover, their minute size is an advantage, as they are car- 

 ried into any little chink or cranny in the bark, while a larger or 

 heavier seed, even if borne against a suitable tree, would be more 



Fig. 17. Cardamine chenopodifolia. a a, ordinary pods ; b, subterranean pods. 



likely to drop off. In the genus JSfeumannia, the small seed is pro- 

 duced at each end into a long filament which must materially increase 

 its chances of adhering to a suitable tree 



Even among terrestrial species there are not a few cases in which 



