1906] CURRENT LITERATURE 453 
or cease to function, their work is taken up by the epidermis. The cells of this 
develop a vast amount of chlorophyll and all movement is to and from them.”’ 
“Only those cells exposed to light function as cotyledons, and hence all flow 
of material is to and from the lightest side. Light is then an indirect cause 
of the location of the buds, while the principal factor is determining the loca- 
tion in relation to movements of food materials in plants.” This would make 
it entirely a question of nutrition, a rather unusual condition, for in most 
cases of regeneration in plants, and in animals too, regeneration will occur 
while the parts concerned are but poorly nourishe 
Ficpor" cut off the apices of young fern fronds piepenciglir to the median 
axis and very close to the tip, removing only a fraction of a millimeter of the tip. 
Replacement occurs slowly, but the new tips become forked, two apical cells 
forming, one on each side of the midrib. The two sides extend outwards, leaving 
the midrib sunken in the center. By cutting very young fronds with a median 
longitudinal cut about 5™™ deep, regeneration of each half occurs, and a sub- 
sequent branching of the frond is obtained. The fern used was Scolopendrium 
Scolopendrium, a variety of which (daedalea) occasionally occurs in nature with 
forked fronds, and Frcpor considers this probably due to wounding of the tips 
by insects and subsequent regeneration. 
HILDEBRAND'S has continued his studies on regeneration in Cyclamen, 
and presents further interesting observations. Two forms are mentioned, 
Cyclamen Miliarakisii and C. creticum. On the former, when the leaf blade 
of the cotyledon is removed, leaving the petiole, there arise a little below the 
place of removal, froma point on one side of the petiole, four small leaves, each 
having the form of the cotyledon, and the four together aggregating the size 
of the blade removed. Each is borne on a distinct petiole of sufficient length 
to bring the blades out far enough to prevent shading each other. In this the 
author sees an exceptional example of the principle of utility in the development 
of plant structures. In the other species, C. creticum, HILDEBRAND observe 
a plant having no cotyledons, but upon which, arising from the center of the 
tuber, were three leaves with long petioles. Each blade was almost one- -third 
the size of the round cotyledon-blade, and in form intermediate between the 
cotyledon -and the foliage leaves. Investigation showed that the cotyledon 
had been destroyed to the base, and these three leaves arose together from 
the axis of the plant just below the point of attachment of the cotyledon, The 
originated as entirely new structures, replacing cotyledons, and were intermediate 
in form between these and the later leaves. 
4 Ficpor, W., Ueber bcaswageres der Blattspreite bei Scolopendrium Scol- 
opendrium, Bes Deutsch. sell. 24:13-16. 1906. 
ts HILDEBRAND, FRIEDRICH, Ueber eine eigentiimliche Ersatzbildung an einem 
Keimling yon Cyclamen Miliarakis:i und einem anderen von — creticum 
Ber. Deutsch. Bot. Gesell. 24: 39-43- 1906. 
