144 HETEROPHYLLY [ch. 



Lyte's Herball (i ^'j'^') contains a vivid description of hetero- 

 phylly in the Water Buttercup a free translation of that given 

 in Dodoens' Histoire des Plantes of 1557. Since this description 

 is also noteworthy for its insistence on the influence of external 

 conditions upon the form of the leaves, it may be cited here. 



" Amongst the fleeting [floating] herbes, there is also a cer- 

 tayne herbe whiche some call water Lyverworte, at the rootes 

 whereof hang very many hearie strings like rootes, the which 

 doth oftentimes change his uppermost leaves according to the 

 places where as it groweth. That whiche groweth within the 

 water, carrieth, upon slender stalkes, his leaves very small cut, 

 much like the leaves of the common Cammomill, but before 

 they be under the water, and growing above about the toppe of 

 the stalkes, it beareth small rounde leaves, somewhat dented, or 

 unevenly cut about. That kind which groweth out of the water 

 in the borders of diches, hath none other but the small jagged 

 leaves. That whiche groweth adjoyning to the water, and is 

 sometimes drenched or over- 

 whelmed with water, hath also 

 at the top of the stalkes, small 

 rounde leaves, but much more 

 dented than the round leaves of 

 that whiche groweth alwayes in 

 the water." 



The water and land leaves of 

 Ranunculus Purschii are illus- 

 trated in Fig. 92 A and B, The 

 heterophylly of the Water 

 Buttercups has been subjected 

 to a great deal of critical investi- 

 gation. It has been shown that, 

 in the case of Ranunculus aqua- 

 tilis^ L.^, it is impossible to say 

 at an early stage whether a leaf 

 rudiment will produce the floating or submerged form. Up 

 1 Askenasy, E. (1870}. See also Rossmann, J. (1854). 



Fig. 92. Ranunculus Purschii, Rich. 



A, water leaf (^ na,t. size) and B, leaf 



of the land form (reduced). [Goebel, 



K. (1891-1893).] 



