THE WATER-PLANTAIN TRIBE. 209 



thor this plant is an Exogen or an Endogen? Its 

 leaves are in some measure those of both classes ; and 

 not exactly of either. The parallel ribs and netted 

 intervals are, of the two, most like those of an Exogen. 

 The branched vcrticUlate inflorescence is most common 

 in Exogens ; but then it occurs continually among 

 grasses. The ternary flowers are those of Endogens, 

 but, again, there are many cases among Exogens where 

 the ternary structure also exists : as in the Hepatica 

 which is a Ranunculaceous plant. So far, therefore, as 

 the structure of those parts you have been able to 

 examine is concerned, the evidence seems pretty well 

 balanced. 



Perhaps affinity may settle the point. What is 

 Alisma most like ? You have no where seen in En- 

 dogens an example of numerous carpels and stamens ; 

 six, or three, or fewer, having been the prevailing 

 number. We do not, therefore, seem likely to find a 

 parallel in that class. Turn to Exogens, and espe- 

 cially to those which have numerous hypogynous 

 stamens and carpels ; and the memory immediately 

 rests upon the Crowfoot Tribe. In that natural 

 order, although the leaves are usually veined in 

 the most legitimately Exogenous manner, yet in 

 some, in the water species in particular, such as the 

 common tongue-leaved Crowfoot (Ranunculus Lingua), 

 the veins are disposed upon a plan strikingly similar 

 to that of Alisma ; in Pileworty which is a species of 

 Crowfoot (Ranunculus Ficaria), there are only three 

 sepals ; and in the Mousctail (Myosurus minimus), the 

 stamens fluctuate between five and twenty. The fruit 



VOL. II. P 



