NOTES ON HETEROPHYLLY.
121
some with a large terminal lobe and the rest of the leaf wedge-
shaped and more or less entire; many with pinnate or lyrate
leaves, with the side lobes either oval or acuminate or growing
out into sickle-shaped hooks. In extreme cases these long-
tailed leaflets give quite a striking effect. All these forms may
be found within a few feet of each other. Seedlings of Buckhorn
Plantain, Plantago corouopus, growing on bare soil near the sea,
also show every variety from entire to deeply pinnatifid leaves;
usually the entire leaves are on the younger plants.
HETEROPHYLLY ASSOCIATED WITH JUVENILE AND
MATURE FOLIAGE.
Herbaceous Land Plants.—In these plants the lower or
root leaves are so often of a different shape or differently cut
from the upper stem-leaves that abundant examples occur to
the mind. In Buttercups the root leaves are usually less
deeply divided than the upper ones.
Goldilocks, Ranunculus auricomus, has the long-stalked root
leaves nearly round and little cut, while the upper leaves are
sessile and divided into narrow segments A similar contrast
between root and stem leaves is seen in Ranunculus sceleratus;
in Musk Mallow, Malva moschata, also, the first root leaves are
far less deeply divided than the later ones or than the stem
leaves. The same contrast is seen in many Umbelliferae.
Cow-Parsnip, Heracleum Sphondylium, has the first seedling
leaves undivided, while the older ones are, successively, three-
lobed, three-foliate and pinnate. Smyrnium perfoliatum, a
South European species, found last summer as an alien by my
friend Miss Greenaway on waste ground near Mitcham, Surrey,
illustrates strong contrast between pinnate root-leaves and
broad nearly entire stem-leaves. In Horse-Radish, Cochlearia
Armoracia, the lower leaves are cut into deep pinnatifid segments,
while most of the great stem leaves are undivided.
Water Plants.—Many water plants illustrate hetero-
phylly in a striking manner, and the contrast between the
first-formed submerged leaves and the later floating or aerial
leaves is familiar to all.
An example is seen in the Water-Crowfoot, Ranunculus
aquatilis, of our Forest ponds, where the first leaves, even of