DICOTYLEDONE^E. 79 



own roots perish. The twining stems of Convolvu- 

 lacece are a most unaccountable phenomenon ; and are 

 a fit subject for the investigation of the physiologist. 



The next peculiarity of structure requiring notice, 

 occurs in the Bignoniacece, which is the manner in 

 which some of them attach themselves to the bark of 

 trees, rocks, or buildings for support. This is accom- 

 plished by fibrous processes issuing from the bark 

 of the young shoots ; these produce other fibres 

 laterally, which, having flattened ends, seize on the 

 asperities and chinks of the supporting surface, thereby 

 gaining a firm and secure hold. 



The Asclepiadece and Apoci/nece are only remark- 

 able for the curious structure of their flowers and 

 deleterious qualities of their juices. The genus Sta- 

 pelia are succulent plants, consisting of thick fleshy 

 stems, either erect or lying on the ground. Many of 

 them have irregularly quadrangular shoots, bearing 

 flowers of the most grotesque shape and colours, but 

 wholly destitute of leaves. 



Jasmlnece and Olmce may be called household 

 orders, being so well known. That the Fraxinus 

 should be ranked with the olive is rather curious ; 

 but their natural relation is proved by the readiness 

 with which they take, when worked on each other. 



The Ebenacece are worthy of note, because the 

 Diospyros ebenum furnishes one of the most precious 

 and hardest kinds of wood. No other of the Corol- 

 liflorce require remark. 



At the bottom of sub-class Calyciflora are 



