492 : Siosson: THE ORIGIN OF 
neuron, and in the other cuneate, like leaves of young C. r/uzo- 
phyllus. Later, the leaves of all four became cordate at the base, 
like leaves of mature C. rhizophyllus. 
There can be no doubt of the hybridity of these four plants: 
they have shown from the beginning a most curious combination 
of the characteristics of A. p/atyneuron and C. rhizophyllus. 
The leaves have varied from suberect to almost decumbent 
and, though none have taken 
root, some have rested their tips — 
upon the earth. 
That the leaf-blades are inter- 
mediate in outline between the 
leaf-blades of A. platyneuron and 
C. rhizophyllus may be seen from 
figures 1-7, in which the three 
ferns are shown in somewhat 
parallel stages of development, 
A representing leaves of A. platy- 
neuron, B and BB in f. 7, 2; 3) 
g and 7 leaves of the June plant 
of the hybrid, B in f. 5 a leaf, of 
one of the September plants of 
the hybrid from the fourth howe 
pot, and D leaves of C. rhizo- 
phyllus. The blades of the leaves 
of the hybrid combine fairly theif 
texture, which is characteristic of 
A, platyneuron but not of C. 
rhisophyllus, with veins forming 
slightly raised lines on the — 
of the leaf, which is characteristic 
of C. rhizophyllus but not of A. 
platyneuron. Their color, though a lighter and brighter gre? 
than that of C. rhizophyllus, suggests it. 
In one of the hybrid-plants in each pot the veins have been 
wholly free, and in the other, especially in the June plant, the 
veins, though mostly free, have formed a number of areolae. 
In all three ferns when very young the petioles are gree 
FIG. 6. . XX 855i 
