| 
1896 | CURRENT LITERATURE 67 
IN A SECOND CONTRIBUTION on “ The influence of light upon the form of 
Cacti and other plants,’ '* Goebel discusses the dependence of the form of 
the leaves of Campanula rotundifolia upon the intensity of light and intro- 
duces some remarks upon the dependence of the heterophylly of a few other 
plants upon external factors. 
The usual form of Campanula rotundifolia is well known in the northern 
states. The early round leaves, from which it takes its specific name, form a 
radical rosette, but often perish early, so that the name seems very inappro- 
priate when only the linear-lanceolate upper leaves are seen. The erect 
flowering branches arise in the axils of the lower leaves of the rosette and 
normally produce elongated leaves. Goebel was able, by diminishing the 
light, to cause shoots to produce round leaves exclusively until more strongly 
illuminated, when they formed long leaves. Others in weak light produced 
shoots in the upper axils bearing round leaves. But the most instructive case 
was that in which a shoot, after producing normal leaves, gradually returned 
to the development of round leaves, those at the tip of a 20™ shoot being of 
typical orbicular-cordate outline. To determine whether the formation of the 
round * leaves could be suppressed by strong illumination from the beginning, 
or whether the process of development is so ordered that under all conditions 
round leaves appear first, plants were subjected to artificial illumination, 
finally with two arc lamps of 2000 c. p. each. But in no case was the formation 
of round leaves hindered. Goebel argues, therefore, that Campanula rotund- 
ifolia has not inherited the An/age of two (or if one considers intermediate 
forms, many) leaf forms whose appearing is determined by the different 
degrees of intensity of light as a releasing factor, but only the An/age of the 
round form, which under the normal condition of sufficient light is trans- 
formed into the long type, not suddenly but gradually, so that various 
intermediate forms appear. In the course of the ontogeny of an individual 
leaf these intermediate forms do not appear because the transforming factor 
very early directs the development of the leaf Am/age into another course. 
But if this factor be removed the inherited form reappears, as in the cultures 
in weak light.—C. R. B. 
Dr. J. WiEsNER, who has contributed so much to the general subject of 
Physiology, gathers up™ in a rapid review the suggestions he has made in 
regard to the phenomena and terminology of the inequilateral growth of plant 
members. Having summarized the various forms of heterotrophy of tissues 
and members— evidently in many cases a complex phenomenon, which is 
Conditioned on the one hand upon innate peculiarities and on the other upon 
Flora nr I-13. 1896. 
“'Goebel says, apparently by a slip of the pen, “Lan r d of 
“ > gblattform,” instead o 
Rundblattform.” as P . 
“ Berichte der deutschen botanischen Gesellschaft 13 : 481-495. 1896. 
