[Proc. Rot. Soc. Victoria, 21 (N.S.), Pt. I., 1908.] 



Ar'I'. V!. — Note on an Abnormal Developmerd on Leaves 

 of Prunus cerasus. 



By bertha REES 



(Melbourne University). 

 (With Plate X.). 



[Eead 7th May, 1908]. 

 (Coninmnicated by Prof. A. .J. Ewart, D.Sc, Ph.D.). 



The leave.<: in question were found by Mi'. C. French, junr., on 

 trees gi-own in an orchard in South Gippsland. The form of 

 growth was peculiar, and had the appearance of small leaflets 

 developed on the under surface of the large leaves. (Fig. 1.) 

 No such abnormality had been previously recorded, and conse- 

 quently it was of interest to note the relative positions of the 

 tissues in leaf and leaflet, and further to determine whether the 

 orienti.tion of the leaflet depended on the aiTangement in the 

 main leaf, or on light or gravity. 



However, microscopic examination of serial sections (obtained 

 by paraffin embedding) showed : — 



1. That the palisade pai'enchyma was developed on the lower 



surface of the leaflet (i.e., on the side away from the 

 larger leaf), so at first sight it appeared that the posi- 

 tions in the two did not correspond. (Fig. 2.) 



2. That the relative positions of the phloem and xylem 



were also reversed in the same way as was the paren- ■ 

 chyma. (Fig. 2.) 



3. That there was no vascular bundle running do\vn the 



centre of the leaflet, as might have been expected, also 

 that the veins were continuous with those of the main 

 leaf. (Fig. 2.) 

 ■i. That the two longitudinal halves of the apparent leaflet 

 were connected in some instances by epidermis only, 

 and in others by epidermis and a small amount of 

 parenchyma. (Fig. 2.) 



