OP SEVERAL ORGANS. 25 



cases supply the clue, and in others the regularity of 

 form will indicate the nature of the malformation, for 

 in those instances where the cup is the result of ex- 

 pansion, its margin is more likely to be regular and 

 even than in those where the hollow form is the result 

 of fusion. 



Cohesion of several organs by their margins : leaves, &c. The 

 union of the margins of two or more different 

 organs is of more common occurrence than the pre- 

 ceding, the leaves being frequently subjected to this 

 change. Occasionally, the leaflets of a compound leaf 

 have been observed united by their margins, as in the 

 strawberry, the white trefoil, and others. Sometimes 

 the union takes place by means of the stalks only. I 

 have an instance of this in a Pelargonium, in Tropceolum 

 majiiSf and Strelitzia retina ; in other cases, the whole 

 extent of the leaf becomes joined to its neighbour, the 

 leaves thus becoming completely united by their edges, 

 as in those of Justicia, oxyphylla} M. Clos" has ob- 

 served the same thing in the leaves of the lentil Ervum 

 lens, conjoined with fasciation of the stem, and many 

 other examples might be given. Some of the recorded 

 cases are probably really due to fission of one leaf into 

 two rather than to fusion. Although usually the lower 

 portions of the leaf are united together, leaving the 

 upper parts more or less detached, there are some 

 instances in which the margins of the leaf at their 

 upper portion have been noticed to be coherent, while 

 their lower portions, with their stalks, were completely 

 free.' 



Cohesion of the leaves frequently accompanies the 

 union of the branches and fasciation as might have 

 been anticipated. Moquin cites the fenestrated leaves 

 of Dracontmm pertusum, as well as some cases of a 

 similar kind that are occasionally met with, as instances 



D. C, ' Organ. Veget.,' pi. xvii, fig. 3, and pi. xlviii, fig. 2. 



Mem. Acad. Toulouse/ 1862. 



' Bonnet, Becherchcs Us. feuill.,' pi. xxi, fig. 2. 



