1905] CURRENT LITERATURE 73 
influence of organic substances on growth and form. In general, stem growth 
is checked in concentrated solutions. While this is doubtless partly due to the 
increased osmotic pressure, it is evident that chemical factors are also active, 
: since glucose and glycerin solutions of equal concentration give different results. 
4 A final chapter deals with the application of his results to agriculture —HENRY 
4 C. Cowles. 
KrrKwoop'’ has published the results of an extended investigation of Cucur- 
bitaceae, chiefly relating to the development of the ovary and the embryo sac 
} structures. The genera included are Fevillea, Melothria, Apodanthera, Bryon- 
+ opsis, Trichosanthes, Momordica, Luffa, Cucumis, Lagenaria, Benincasa, 
1 Citrullus, Cucurbita, Sicyos, Micrampelis, Coccinia, and Cyclanthera, a remark- 
} able list for one investigator in these days to present in a single paper; but the 
’ 4 work has been under way since 1898. ‘The mass of details will always be consulted _ 
’ for comparison with similar details in other families, and it is important to have so 
_ compact and clear a record. Certain general results, however, should be referred 
‘to even in a brief review. As is well known, the position of the family has always 
a ‘been a problem because of its contradictory characters, but it is generally placed 
', now among the higher Sympetalae. It is interesting to note that Kirkwood has 
‘| discovered that the sixteen genera studied unanimously contradict certain charac- 
F) ters of Sympetalae that have been thought to be fundamental. The ovule of this 
if great group is remarkably constant in its single and very prominent integument, 
4 its very much reduced nucellus, and its elimination of tapetal tissue (the hypo- 
i dermal archesporial cell passing over directly into the mother-cell). In all the 
_ # Cucurbitaceae studied, however, Kirkwood finds the ovules with two integuments, 
| a well-developed nucellus, and tapetal tissue by no means eliminated, but often 
4 very extensive. It seems to the reviewer that just as the single character of poly- 
4 g Petaly arbitrarily applied, has detained the Umbelliferae among the Archi- 
+chla 
Be 
% study of the peculiar pollen tubes reported for the family, or of fertilization and the 
7) development of the embryo. e endosperm is noteworthy for its extensive 
growth and nutritive activity, to which the author has given somewhat detailed 
attention. ‘The general conclusions from the development of the ovary, especially 
the growth of the variable “placenta” and the origin of the ovules, are used in an 
; interesting way to relate the genera in phylogenetic series.—J. M. C. 
f 
he 
FittINGc’s's preliminary report promises a paper which will be of special 
» interest because he has attempted a solution of several of the most fundamental 
problems of geotropism. The behavior of orthotropic organs upon a klinostat 
14 KIRKWOOD, JOSEPH EDWARD, The comparative embryology of the Cucurbi- 
| taceae. Bull. N. Y. Bot. Garden. 3: 313-402. pis. 58-O9. 1904. 
: 15 FITTING, H., Geotropische Untersuchungen. (Vor. Mit.) Ber. Deutsch. Bot 
- Gesells. 22: 361-370. 1904. 
