DEGENEEACY OF FLOWERS. 259 



the same, but do not always reacli the gi-ound, or else pene- 

 trate it very slightly. They all bear fertile flowers. The 

 lowest are apetalous, if completely hypogean [and pre- 

 sumably cleistogamous]. Those which just reach the soil 

 have a corolla of four lobes nearly equal, and resemble the 

 corolla of Veronica. A little higher up, the irregularity of 

 the bilabiate character of Scrophularia is pronounced." 



The preceding quotation is interesting, first in showing 

 Low the subterranean cleistogamous form is derived from 

 the conspicuous flower, and also supplies a hint as to the 

 origin of Veronica, in that it is a 4-merous degradation from 

 a primitive 5-merous genus, which is lost or unrecognizable 

 now, unless it be some member of the subgenus Pygmcea, 

 which has five parts to the corolla.* 



As an illustration where geographical conditions favour 

 the development of autogamous forms of flowers, the follow- 

 ing passage may be quoted : — 



" Herr C. A. M. Lindman has examined the very rich 

 flora of the Dovrefjeld in reference to the arrangements for 

 fertilisation. He finds a distinct tendency to a deeper colour 

 in the flowers than is displayed by the same species in the 

 lowlands, red and blue predominating. The great length of 

 daylight appears to increase the size both of leaves and of 

 flowers, though in some species, on the other hand, the 

 flowers are diminutive in consequence of the low tempera- 

 ture. Crowded masses of small flowers are very common. 

 The number of scented species is comparatively small, 

 though the fragrance is sometimes powerful. The scarcity 

 of insects necessitates that there should almost always be 

 a provision for possible self-fertilisation ; and many species, 

 elsewhere heterogamous, are here homogamous. Notwith- 



* For Miiller's theory of the origin of Veronica, see Fertilisation, etc., 

 p. 465. 



