16 



Miss E. R. Saunders. On a Discontinuous 



shelter, 107 leaves, belonging to 72 different plants, suffered more or 

 less mutilation. Of these the leaf surface was glabrous in 94, inter- 

 mediate in 5, and hairy in 5; in the remaining 3, so much of the 

 leaf was devoured that its character could not be ascertained with 

 certainty.* 



It soon became evident that the individuals in which the uniform 

 character of the leaves was maintained (not only in the seedling, 

 but, as it proved, in the adult stage also) were those which as seed- 

 lings conformed to one or other of the extreme types, the leaves 

 being either very hairy, or else destitute of hairs, except perhaps 

 at the leaf-teeth. On the other hand, the plants exhibiting more 

 than one grade of hairiness were those in which the first formed leaves 

 corresponded to one of the types intermediate between these two 

 extremes ; among these latter the variations in different individuals 

 were always along the same lines, and consisted in a gradual diminu- 

 tion in the number of hairs in successive leaves, until sooner or later 

 a stationary point was reached, after which the character of the leaf 

 surface usually remained constant. f 



In enumerating the various grades cf hairiness occurring in a single 

 individual, I have intentionally disregarded the character of the 

 cotyledons, for the reason that they do not appear to bear any constant 

 relation (as regards texture) to the leaves which follow. In the 

 case of a seedling in which as yet only the cotyledons were developed, 

 I found it impossible to predict with certainty the character of the 

 succeeding leaves. It is true that in nearly all hairy plants the 

 cotyledons were also hairy, and that in many that were smooth the 

 cotyledons were almost glabrous; but exceptions to this rule were 

 not wanting, while in intermediates the cotyledons exhibited every 

 gradation between the two extremes. Hence there was always an 

 uncertainty as to whether hairy cotyledons indicated a hairy or an 

 intermediate plant, and whether smooth cotyledons would be suc- 

 ceeded by glabrous or intermediate leaves. That this want of agree- 

 ment between the cotyledons and the later leaves is a condition not 

 peculiar to this species, but is one of common occurrence, needs no 

 further proof than that furnished by a comparative study of the 

 leaves and cotyledons of other members of the same natural order. J 



* The insufficient protection against such attacks afforded by the marginal tuft3 

 of hairs has already been noticed by Stahl ('Pflanzen und Schnecken,' Jena, 1888, 

 p. 58). 



t The stunted leaves which are sometimes formed at the beginning or the close 

 of a period of vegetation, as, e.g., in late autumn or early spring, may prove excep- 

 tions to this rule; they are often distinctly less hairy than those of normal size 

 borne on the same individuals. But when active growth once more sets in, 

 the new leaves resemble the type previously established in those that developed 

 normally. 



% Lubbock, f On Seedlings.' 



