540 CONSERVATIVE ORGANS. [LECT. X. 



Plate 4), 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. Connate leaves are .in some instances 

 united by a membrane, which stretching from the 

 margins of the opposed leaves, near the base, 

 forms a kind of pitcher around the stem ( 1 6 *) in 

 which the rain-water is retained ; as exempli- 

 fied in Fuller's Teasel, Dipsacusfullonum, which 

 has received its generic name SAJ/axof, or thirsty, 

 from this circumstance. A perfoliate leaf (fo- 

 lium perfoliatum) , (17), is itself perforated by 

 the stem. When leaves embrace the stem with 

 their bases, so as to enclose it as with a sheath, 



they are termed sheathing (vaginantia), ( 1 8, a 



