8 THE AMERICAN BOTANIST 



color in such cases may have a physiological use in protecting 

 the chlorophyll. 



Numerous leaves have a silvery mottled or blotched ap- 

 pearance of more or less definite pattern. Among such are the 

 following: Hydrophyllum appendiculatum, H. macro- 

 phyllum, H. virginicum, Hepatica hepatica, H. acuta, and 

 Chimaphila maculata. Smilax glauca has the same type of 

 markings at least in the young condition. Cucurbita pepo 

 and C. maxima have prominent angular silvery patches, cover- 

 ing the leaf blade, in the angles of the veins. In the Hydro- 

 phylliims, the main variegation usually extends on each side 

 of the midrib and occurs in smaller spots beyond, especially at 

 the notches of the serrations. 



Other plants having mottled or blotched leaves are Ery- 

 thronium americanum, E. albidum, Lamium album, L. macu- 

 latum, Trillium sessile and T. recurvatum. In Trillium sessile 

 the markings are usually very prominent, while in T.recurva- 

 tum they are not always visible. Arisaema triphyllum, has 

 beautiful reddish-brown and whitish spots on the sheathing 

 bracts, petioles and peduncles but the leave blades are green. 



The plants of the greatest interest are those with definite, 

 often symmetrical patterns, which can have no relation to the 

 general structure. For here we come face to face with the 

 difficult problem of symmetrical coloration in general. Oxalis 

 grandis has beautiful leaves with an ornamental brown mar- 

 gin. Euphorbia marginata has milk-white bands on the leaves 

 surrounding the flower clusters. In the second example the 

 claim might be made that the striking color patterns around 

 the flowers were developed through insect selection. In the 

 first case such an explanation would, of course, be out of the 

 question. In Euphorbia maculata and E. nutans, the leaf 

 blades have an irregular oval dark-red spot in the center, the 

 latter species having in addition the white streak over part of 



