FISSION OF LEAVES. 



63 



the leaves of which latter thus resembled those of TJrtica 

 hiloha, which are habitually bilobed at the summit. M. 

 Clos' mentions an instance where the terminal leaf and 

 first bract of Orchis savibuciua were divided into two 

 segments. The same author also mentions the leaves 

 of Anemiapsls callfornica, which were divided in their 

 upper halves each into two lobes also leaves of a lentil 

 springing from a fasciated stem and completely divided 

 into two segments, but \\ath only a single bud in the 

 axil. The axillary branches in like manner showed 

 traces of cleavage. Fig. 26 represents a case of this 

 kind in Lamiiim album, conjoined with suppression of the 

 flowers on one side of the stem. I have also in my her- 

 barium a leaf of Arum maculatum^ with a stalk single at 

 the base, but dividing into two separate stalks, each bear- 

 ing a hastate lamina, the form of which is so perfect that 

 were it not from the venation of the sheath it would 

 be considered that there was here a union of two leaves 

 rather than a bifurcation of one. A garden Pelar- 

 gonium presented the same appearance. 



Fio. 27. Bifurcated lea o{ Pelargonium. 



" Fern fronds are particularly liable to this kind of 

 subdi\4sion, and they exhibit it in almost every degree, 

 from a simple bifurcation of the frond to the formation 

 of large tufts of small lobes all formed on the same 

 plan by the repeated forking of the pinnules. These 

 may be considered as cases of hypertrophy. 



Moquin-Tandon, at a meeting of the Botanical Society 



' ' Mom. Acad. Scicn. Toulouse,' 5th series, vol. iii. 



