NOMENCLATURE OF THE LEAF. 57 



ra. Imbricated placed like tiles upon a honse, as in common 

 cypress and spiral aloe. (F. 46.) 



B. Rose-like when the leaves are imbricated in a manner re- 

 sembling a rose. (F.50.) 



o. Crowning when they terminate the stem or branches like a 

 plume of feathers, as in the palm tribe. 



p. Remote when at an unusual distance from each other. 



12. Duration: From the time which leaves live, 

 they are either called caduous, deciduous, withering or 

 persistent. 



a. Caduous falling off in the middle of the summer. 



b. Deciduous falling off at the approach of winter. 



c. Withering green the whole year, and falling off as the new 

 ones appear. 



d. Persistent lasting many years and always green. 



13. Insertion: According to the peculiar attach- 

 ment which leaves have, they are either described as 

 being sessile, decurrent, perfoliate or petiolate. 



a. Sessile without foot-stalks, lying immediately on the stem or 

 branch, as in officinal soap-wort and common butter-wort. Each leaf 

 represented in F. 54, is sessile. The varieties are 



Embracing clasping the stem with their bases, as in the milk 

 thistle and white poppy. (F. 72.) 



Connate when the embracing leaves are opposite and united 

 at their bases, as in the jagged teasel. (F. 51.) 



Sheathing when leaves embrace the stem with their bases, so 

 as to enclose it with a sheath. (F. 56.) 



Equitant when being opposite, they clasp each other, as in 

 the Iris tribe. 



b. Decurrent when the lamellar part of the leaf runs down the 

 stem or branch, as in great mullein. (F. 49.) 



c. Perfoliate when the stem runs through the leaf, as in thorough- 

 wax and perfoliated uvularia. (F. 73.) If the union be in the 

 whole, or nearly the whole breadth of the leaves, so as to give the 

 two leaves the appearance of being united into but one leaf, they are 



