Hart’s-Tongue 45 
In the development of the leaf of Phyllitis scolopendrium the 
blade assumes successively the following forms: spatulate; spatu- 
late-oval or suborbicular; suborbicular or roundish-ovate or 
ovate-oblong, becoming cordate; ligulate-cordate; and oblong- 
lanceolate or lanceolate or linear-lanceolate with cordate or auric- 
ulate base. 
The spatulate leaf contains either a simple vein or an incipi- 
ent midvein which does not extend beyond two basal primary 
branches. The midvein is evident in succeeding leaves. It 
gradually lengthens and sends out successive primary branches, 
and is finally contained in a midrib. 
The basal primary branches of the midvein may be once 
forked or even occasionally simple at first. They vary, but are 
mostly more complex than the primary branches above them. 
As development of the blade progresses they branch more and 
more, and in the mature leaves are markedly complex. 
The primary branches above the basal mostly vary at first 
from simple to once forked, but gradually become more com- 
plex. In the mature leaves they vary from once to three times 
forked, excepting the extreme uppermost, which, appearing later 
than those below, sometimes do not develop beyond the simple 
stage. 
The veinlets are mostly clubbed at apex. They end near the 
leaf’s margin: the veinless border is often pronounced. 
Occasional areole occur in the mature leaves. I have seen 
only one areole, near the midvein of a very small leaf, in the 
young leaves. 
At first the leaf-blade is decurrent on the petiole—so much 
so in the narrower of the spatulate leaves that the petiole resem- 
bles a winged midvein. 
