50 Robinson : Spines of Fouquieria 



Fouqnieria to test the effect of changed climatic conditions upon it, 

 but it has been observed that in greenhouses the leaves remain 

 attached to the plant a number of months, while in nature they are 

 usually cast off at the end of a few weeks ; and in some years, in 

 the wild state, no leaves are produced. Lothelier's experiments 

 upon the barberry (Rev. Gen. Bot. 2 : 276. 1890) showed that 

 when grown in moist air it loses its spines. Henslow (Jour. Linn. 

 Soc. Bot. 30: 223. 1895) has made a similar observation for Ononis 

 spinosa, one variety of which living upon sandy shores is covered 

 with spines, but becomes less and less spinose in favorable condi- 

 tions or under cultivation, and he cites the cultivated apple and 

 pear as similar examples. Miss Dale (Ann. Bot. 15 : 59> 497- 

 1 901) has noted that when tubers of Dioscorca sent out shoots in 

 light and without moisture, the leaves were scarcely developed at 

 all, and the same thing may now be observed in the Museum of 

 the New York Botanical Garden, where tubers of Dioscorea in the 

 exhibition cases have sent out branches, the leaves of which are 

 greatly reduced. 



There is a wide gap between Fouqnieria and Cantiia, its near- 

 est relative among the Polemoniales, which fact together with the 

 small number of species in the genus, its confinement to a limited 

 area, and its stability may be taken to indicate that it is an old 

 form, though there is no geological record so far as is known of 

 any similar spine-bearing form. 



