1907] CURRENT LITERATURE 147 
family containing the genera Balanites, Agialida, and Agiella (new); the same 
author (zdem 261-271) also breaks up the Boraginaceae into 4 families, Boraga- 
ceae, Ehretiaceae, Cordiaceae, and Heliotropiaceae.—C. V. Prper (Contrib. U. 
S. Nat. Herb. 10:1-48. pls. 1-15. 1906), in a revision of N. Am. species of 
Festuca, recognizes 34 and describes 3 as new.—A. A. HELLER (Muhlenbergia 
2:177-256. 1906), in an account of botanical exploration in California during 
1906, in which numerous species are noted and nomenclatural changes made, 
describes new species in Taxicoscordion, Eriogonum (2), Mirabilis, Lupinus (4), 
Hesperastragalus, Anogra, Chylisma, Phlox, Phacelia, Conanthus, Cryptanthe 
(2), Amsinckia, Pentstemon (2), and Orthocarpus.—Paitrm Dower (Bull. 
Torr. Bot. Club 33:547-556. pls. 18-22. 1906), in a revision of N. Am. species 
of Calceolaria, recognizes 16 and describes 6 as new.—J. M. C. 
Formative influence of light.—Prrrce has extended his studies on irritability 
in plants from algae to liverworts and ferns, recording the effect of light upon 
germination and early growth in Anthoceros jusiformis, A. Pearsoni, Fimbriaria 
californica, and Gymnogramme triangularis, and its effect on form in later 
stages of growth.?3 He finds that germination is dependent upon light of unde- 
termined intensity, and that direction of growth and of successive cell division is 
determined by the direction of light. The direction of light also profoundly 
modifies the form of the thalli of the liverworts. This was most marked in 
Anthoceros. On a clinostat they tend to become solid, erect, and cylindrical, 
conic or vasiform, with radial structure instead of dorsiventral. The author 
holds that his early results support the hypothesis that, aside from what is-actually 
transmitted from parents to offspring, likeness is due to likeness or identity of 
the physical environment, and that these factors are as essential determinants as 
the substance transmitted. Unfortunately PErRcE’s experiments were inter- 
rupted by the earthquake of April 16, so that conclusive tests have not been made 
in all cases. The work will be continued.—C. R. 
Assimilation of organic acids by algae.—An interesting contribution to our 
know'edge of the power of assimiJation of carbon compounds hy autotrophic 
plants has been made by Tr&Bovx.?4 This investigator experimented with some 
forty species of the lower algae, testing their power of assimilating various organic 
acids, which were given in the form of potassium or ammonium salts. Cultures 
were kept in absolute darkness. It was found that about one-half of the species 
flourished under the cultural conditions with an organic acid as the only source 
of carbon; and that of all the acids used acetic acid was most readily assimilated, 
while acids with larger carbon chains were assimilated in only a few cases. I 
some cases aminoacids were used with accompanying escape of ammonia. 
23 PerrcE, G. J., Studies of irritability in plants. Annals of Botany 20:449-465. 
Pl. 35. 1906. ; 
24 TréBoux, O., Organische Sauren als Kohlenstoffquelle bei Algen. Ber. 
Deutsch. Bot. Gesells. 23: 432-441. 1906. 
