68 NOMENCLATURE OF THE LEAF. 



d. Hoary when the secretion is a dry, very fine, waxy powder, 

 of a blueish colour, devoid of gloss, and easily wiped off. 



e. Mealy when it resembles a mealy powder. 



22. Colour : The colour of leaves is not unfrequently 

 a subject of botanical distinction, and hence they are 

 sometimes described as being coloured, variegated, spot- 

 ted, or striated. 



a. Coloured being of any other than a green colonr, as in the 

 nmaranthus tricholor. 



b. Variegated when there is an intermixture of colonr, as in the 

 round-leaved mint. 



c. Spotted when the colour is in spots or blotches, as in the 

 spotted and officinal lung-wort. 



1. Striated when marked with coloured lines, as in the reed-like 

 eanary-graM. 



23. Substance: When the substance of the leaf is 

 to be considered in describing plants, the terms rigid, 

 membranous, chaff-like, chartaceous, fleshy, leathery, 

 and succulent are employed. 



a. Rigid easily broken on being bent, as in the butcher's broom 

 and Scotch fir. 



b. Membranous when there in scarcely any pulp between the 

 external membranes of the leaf, as in the orange-tree and Die leaves 

 of many plants. 



c. Chaff-like when the leaf is dry, or apparently sapless, and 

 somewhat translucent. 



d. Chartaceous when it resembles paper, as in the draco ter- 



e. Fleshy-when it is thick, and consists chiefly of a juicy but 

 firm cellular parenchyma, as in the house-leek, 



f. Leathery when it is thick, tough and elastic, as in the misletoe 

 and changeable hydrangea. 



g. Succulent when it is thick, and consists chiefly of a juicy 

 and oft cellular substance, as in the hedge-hog fig-marygold. 



