1914] CURRENT LITERATURE os 543 
_ biological science on account of the lack of experimental methods of investiga- 
‘tion, and he has Soneeaey oe 4 indicate certain classes of prob- 
lems which ertain.species, for example, 
occupy habitats so diverse that there seems legitimate ground for doubting 
whether the different forms are specifically identical. Amphibious species of 
Polygonum furnish striking examples of form variation and specific relations 
only to be determined by extensive experimental cultures. Here he recom- 
mends that ‘‘accommodations” be limited to transformations of individuals 
in response to changed environment, and “adaptation” to those of species, the 
former not being hereditary, but the latter being transmitted to offspring. 
The author also urges the investigation by experimental methods of all ex- 
amples of apparent multiplicity of origin of species, and of natural hybrids 
and mutations.—Gro. D. FULLER. 
Vascular anatomy of the Cycadophytes.—Miss BANCRoFT™ has traversed 
the evidence of the relationship between the vascular anatomy of the Cycado- 
filicales and the Cycadales. The particular vascular type of Cycadofilicales 
from which the cycad line has developed is the problem to which at least three 
answers have been given. Scorr favors origin from the Lyginodendron type; 
WorSDELL from the Medullosa type; and Miss pE FRAINE from a situation 
represented by Swicliffia, which rather mediates between the two preceding 
views. iss BANCROFT has done good service in bringing the whole evidence 
of this critical situation together, and has reached the conclusion that the 
s 
the particular origin of a given group, it will generally be found that the dis- 
pute can be arbitrated by | tentilg all of the groups to a common origin.— 
j. M: €. 
Leaf and root.—Many find difficulty in identifying a stem in some vascular 
plants. CHAUVEAUD” diagrams the first leaf and root of Ceratopteris thalic- 
troides and calls the combination a phyllorhiza; the second leaf with its root 
constitutes the second phyllorhiza, etc. The fu portions are commonly 
called the stem. Cordyline anstralis presents a similar condition. In dicotyls, 
the first two phyllorhizas are not separated in time or space; they have a fused 
portion, the stem, and a common root. Why it should make any difference as 
to whether the fusion exists from the start, or occurs a little later, is not entirely 
clear. However, it must be admitted that even in some plants with two cotyle- 
dons, like the cycads, the two categories, leaf and root, seem sufficient for the 
8 Bancrort, NELLIE, Pteridosperm anatomy and its relation to that of the 
cycads. New Phytologist 13:1 and 2:41-68. jigs. 20. 1914. 
9 CHAUVEAUD, GusTAVE, La constitution et l’évolution morphologique du corps 
chez les plantes vasculaires. Compt. Rend. 158:343-346. figs. 8. 1914. 
