OF THE FULCRA. 167 



many genera allied to them, the stipulas are united 

 laterally to the footstalk, /. ]\6. See Potentilla 

 alba, t. 1384. In all these cases they are extrafo- 

 liacecE, external with respect to the leaf or foot- 

 stalk ; in others they are intrafoUacece, internal, and 

 are then generally simple, as those of Poli/gonum, 

 t. 1382, 756, &c. In a large natural order, called 

 Ruhiacecp, these internal stipulas in some cases em- 

 brace the stem in an undivided tube above the inser- 

 tion of the footstalks, like those of Polygonum]w^l 

 mentioned ; in others, as the Coffee, Coffea arabica, 

 and the Hamellia patens, E.vot. Bot. t. 24, they are 

 separate leaves between the footstalks, but meeting 

 just above their insertion. The Europ^ean Ruhiacece. 

 have whorled leaves, as Asperula, Galium, Riibia;^ 

 &c. ; but Asperula cijnanchica, EngL Bot, t, ^3, has 

 sometimes two of its four leaves so small as to look 

 like stipulas, seeming to form an intermediate link 

 between such as have whorled leaves^ and such as 

 have opposite ones with stipulas. The next step 

 from Asperula is Diodia, and then Spermacoce, In 

 the two last the bases of the stipulas and footstalks 

 are united into a common tube. 



Some stipulas fall off almost as soon as the leaves 

 are expanded, which is the case with the Tulip-tree, 

 Liriodendron tullpifera ; in general they last as long 

 as the leaves. 



The absence or presence of these organs, thougli 

 generally an indication that plants belong to the 



