ELEMENTS OF STRUCTURAL IIOTANY. 70 



In the palmate or digitate forms, the leaHets spread 

 out from the end of the petiole, aud, iu describing them, 

 it is usual to mention the number of divisions. If there 

 are three, the leaf is ( ri-foUolate ; if there are five, it is 

 quinquejoliolate. 



115. In the examination of the Mallow, we found a 

 couple of small leaf-like attachments on the petiole of 

 each leaf, just at the junction with the stem. To these 

 the name siipidca was given. Leaves which have not 

 these appendages are e.vvtiinthtlc. 



110, Besides the characters of leaves mentioned 

 above, there remain a few others to be noticed. With 

 regard to their surface, leaves present every gradation 

 from perfect smoothness, as in Wintergreen, to extreme 

 roughness or woolliness, as in the Mullein. If hairs are 

 entirely absent, the leaf is ijlnhwus ; if present, the 

 degree of hairiness is described by an appropriate ad- 

 verb ; if the leaf is completely covered, it is villous or 

 rillose ; and if the hairs are on the margin only, as in 

 our Cliutonia, it is ciliiw. Some leaves, like those of 

 Cabbage, have a kind of bloom on the surface, which 

 may be rubbeu oil with the fingers ; this condition is 



described as (jlancvus. 



117. A few plants have anoma- 

 lous leaves, Thoseof the Onion 

 are jiUform. The Pitcher Plant 

 of our Northeru swamps has very 

 curious leaves (Fig, 181), appar- 

 ently formed by the turning in and 

 cohesion of the outer edges of an 

 ordinary leaf, so as to form a tube, 

 closed except at the top, and arme«l 



b 



