ae 
1913] CURRENT LITERATURE 519 
that the peripheral cells, irrespective of their form and thickenings, show a 
smaller number of plastids and oil bodies than the other cells of the leaf; that 
they are frequently distinguished from the flat cells by a greater capacity for 
taking up aqueous methylene blue and other basic anilin dyes, as well as by a 
greater blackening with silver nitrate; that the cells which color most strongly 
are in general those from which regeneration shoots develop and that the 
greater capacity for taking up color is not due to tannin. He concludes that 
the peripheral cells contain materials which are of significance for the pro- 
duction of adventitious shoots; that transportation of this material is very 
possible and consequently any cell of the leaf may thereby become capable of 
regeneration.—W. J. G. LANnp. 
The androecium of Parnassia.—Mrs. ARBER*® has made an anatomical 
investigation of the stamens of Parnassia, and has applied the results to the 
problem of the affinities of the genus. The vascular strands for the stamens 
arise at a lower level than those for the staminodia, and the two sets are 
independent. This seems to confirm the view that the staminodia represent 
an inner set of stamens. In P. palustris the vascular strand traversing the 
filament is mesarch, ‘‘and there are indications of numerous phloem groups 
arranged round the xylem.” This is thought to mean the presence of vestigial 
vascular strands which indicate that each stamen of Parnassia is reduced from 
an ancestral fascicle of stamens, such as occurs in Hypericum. DRuDE&’s view 
that Parnassia deserves to represent a family of its own, related to Saxi- 
fragaceae, Droseraceae, and Hypericaceae, is confirmed, and the view is 
expressed that the affinity between Parnassia and the Saxifragaceae “has been 
somewhat overestimated.”’—J. M. C. 
The life history of Thelygonum.—lIn a study of Thelygonum from the ger- 
mination of the seed to the mature embryo, SCHNEIDER“ deals with gross 
morphological features, the development of both staminate and ovulate 
flowers, the reduction divisions, the development of the gametophytes, fer- 
tilization, and the development of the embryo and seed coats. In the cyto- 
logical portions of the paper, it is seen that the root tips have 20 chromosomes 
arranged in definite pairs, the reduced number is 10, and fertilization is of the 
usual double character. In conclusion, the author agrees with HALuier in 
Placing the Thelygonaceae near the Haloragidaceae. While there is still 
toom for complete life history studies of new or unusual plants, in most cases 
the time has come for intensive work on special features. In this case it looks 
as if it might have been worth while to look for a differentiation among 
chromosomes.—C, J. CHAMBERLAIN. 
ear 
4s ARBER, AGNES, On the structure of the androecium in Peres and its bearing 
on the affinities of the genus. Ann. Botany 27:491-510. pl. 34. 
“ SCHNEIDER, Hans, Morphologische und tad ei Unter- 
Suchungen an Thelygonum Cynocrambe L. Flora 106:1-41. figs. 23. 1913 
