448 



FERTILIZATION AND FORMATION OF FRUIT IN PHANEROGAMS. 



fig. 340^) and in the Winter Green {Pyrola, fig. 340^), the holes and slits are not, 

 formed at the apex of the fruit, which is directed downwards, but at its base, close 

 to the insertion of the stalk. This position of the apertures would render thei 

 inside of the capsule liable to wetting fi-om rain, &c., and the contained seeds toj 

 injury therefrom, were it not for the fact the openings are closed when this danger 

 threatens. The wall of the capsule is very hygroscopic, and the slits and valves 

 quickly close in damp weather. In fig. 340 several examples of this opening and I 



Fig. 340.— Protection of seeds agaiust wet. 



« Capsules of Campanula rapunculoides in dry, i' in wet weather. 2 Capsule of Lychnis diurna in dry, 3' in wet weather 

 3 Capsules of Linaria Macedonica in dry, s' in wet weatlier. ■» Capsules of Cerastium macroearimm in dry, ■•' in wet 

 weather. ' Capsules of Silene nutans in dry, «' in wet weather. 6 Capsules of Pyrola chlorantha in dry, «' in wet weather. 

 ' Capsules of Gymnadenia Conopsea in dry, ?' in wet weather. 8 Capsule of Pinguicula vulgaris in dry, 8' in wet weather. 



closing are represented. In the already mentioned capsule of the Catchfly (fig. 340*) 

 the aperture at the summit is guarded by a number of divergent teeth ; the same 

 is true in the case of those of. various species of Toadfiax (e.g. Linaria Macedonica , 

 fig. 340 ^). In Cerastiwm macrocarpum (fig. 340*) the opening is directed laterally, 

 and in the Campion (Lychnis diurna, fig. 340^) the capsule is erect with re volute 

 teeth. In the Bellflower (e.g. Campanula rapunculoides, fig. 340^) small, circum- i 

 scribed portions of the wall near the base fold back as valves, giving rise to as ! 

 many a.pertures; in the Winter Greens (e.g. Pyrola chlorantha, fig. 340^) a number ; 



