244 
The Ohio Naturalist. 
[Vol. XI, No. 2, 
The leaf-markings distinguished in the second group, namely, 
those depending on some structural peculiarty, are perfectly 
normal and may also be present generally or only on some indi- 
viduals. The leaves may be covered with minute spots or dots 
caused by internal glands as in Hypericum maculatum where the 
dots are often black or dark blue, and as in Boebera papposa 
where they are oval in shape and of an orange color. In most 
species the dots or punctations are, however, too small to be seen 
by the unaided human eye, although conspicuous under a lens. 
Nelumbo lutea has a peculiar light-colored marking in the center 
of the large peltate leaf that has some resemblance in outline to 
certain species of beetles. The marking is purely structural and 
accidental, yet were green beetles in the habit of frequenting 
these leaves it might be cited as a remarkable case of mimicry. 
The most common markings of this general type are those 
which follow the venation of the leaf-blade, often forming retic- 
ulations. Examples of species with red veins and reticulations 
are Hieracium venosum, Viola hirsutula, and Rumex obtusifolius. 
Argemone mexicana is perhaps the most striking example among 
those with white markings over the veins. The leaves of Mitchella 
repens show a pale-green narrow stripe over the midrib and 
Euphorbia nutans has part of the midrib marked by a white 
streak. The leaves of Peramium pubescens has a beautiful white 
reticulation over a dark-green background, with occasional white 
blotches. 
The most interesting examples of leaf workings, however, 
come in the third group designated above. In the first place, the 
leaf blade may be some permanent, uniform color other than 
green. Oxalis rufa is a plant of this character. The color in 
such cases may have a physiological use in protecting the 
chlorophyll. 
Numerous leaves have a silvery mottled or blotched appear- 
ance of more or less definite pattern. Among such are the fol- 
lowing: Idydrophyllum appendiculatum, H. macrophyllum, H. 
virginicum, Hepatica hepatica, H. acuta, and Chimaphilamaculata. 
Smilax glauca has the same type of markings at least in the young 
condition. Cucurbita pepo and C. maxima have prominent 
angular silvery patches, covering the leaf blade, in the angles of 
the veins. In the Hydrophyllums, 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 Erythro- 
nium americanum, E. albidum, Lamium album, L. maculatum, 
Trillium sessile and T. recurvatum. In Trillium sessile the 
markings are usually very prominent, while in T. recurvatum they 
are not always visible. Arisaema triphyllum has beautiful red- 
dish-brown and whitish spots on the sheathing bracts, petioles 
and peduncles but the leave blades are green. 
