Suckling. — Leaf -anal amy of 'frets and Shrubs on Port Hills. 181 



Leaf-anatomy. 



The plants of which the leaf-anatomy was studied were selected as repre- 

 sentatives of the following plant-forms : (1 ) Lianes, (2) deciduous trees, 

 (3) evergreen trees, (4) semi -parasites. 



Parsonsia heterophylla A. Cunn. 



This plant is a liane all through its life, not assuming different habits, 

 but the leaves at different ages are of most diverse shapes. There are all 

 transitions, from orbicular to linear, oblong, and partly lobed. The leaf of 

 the mature plant is oblong or ovate, subacute, entire, varying in size from 

 4m. to 8m. long, 2 m. to 3 cm. broad, and may have a few hairs on the 

 upper surface, which the young leaves seldom have. There is no essential 

 difference in the anatomy of the young and adult leaf, but in the former 

 often the row of cells next to the lower and upper epidermes contains 

 anthocyan as well as chloropyhll. and this gives the leaf a copper-coloured 

 appearance. (See fig. 1.) 



} 



1OT 



Fig. 1. 



Fig. 2. 



Fig. 1. 

 Fig. 2. 



-Upper epidermis of Parsonsia heterophylla leaf, showing hair ; x 41 8. 

 -Lower epidermis of same ; x 418. 



Leaf -anatomy . — The leaf-anatomy of one of the lianes, Parsonsia hetero- 

 phylla, was studied, and compared with that of Tetra/pathaea ausiralis, with 

 a view to finding in them some of the anatomical characters peculiar to 

 climbers. 



The epidermis is covered with a thick striated cuticle, and is composed 

 of rather large cells. Unicellular hairs often occur on the upper and some- 

 times on the lower surface, but not thickly enough to affect transpiration. 

 These hairs take on a bright-red colour with eosin, while the other epidermal 

 cells remain unstained. The epidermis is two-layered above the midrib. 

 Stomata occur only on the lower surface, with which they are level. 



The palisade layer is three or four eel's deep, tightly packed, with chlo- 

 rophyll grains distributed throughout the cell. Each cell contains a con- 

 spicuous oil-drop, soluble in ether. The palisade tissue composes about a 

 quaiter or one-third of the thickness of the leaf. The cells of the spongy 

 parenchyma are loosely arranged, and contain fewer chloroplasts than the 



