No. 377.] REVIEWS OF RECENT LITERATURE. 369 
flasks were opened. No living bacteria were present in any of 
them, nor were the fluids able to produce tubercles when added to 
the roots of plants growing in sterile earth. Under these conditions 
the germs were not able to assimilate free nitrogen. 
8. It is not clear in just what way the tubercles originate. Their 
production is due to the action of specific organisms, but these are 
not always capable of causing them, as the frequent failures showed. 
The author was not able to produce them by direct inoculations, not 
even in the tissues of young roots and stems. He thinks that 
possibly infection takes place only through young root hairs. Con- 
trary to Laurent, the time of year makes no difference ; neither does 
the age of the plant, as Nobbe has also shown, since tubercles were 
obtained both on the roots of seedlings and on those of well-devel- 
oped plants. Gain’s observation that infections are more numerous 
in a damp soil is confirmed. Erwin F. SMITH. 
Recent Studies of Asarum. — The wild gingers of the Eastern 
and Middle United States, concerning the specific definition of which 
some doubt has long been felt, form the subject of papers by Bick- 
nell in the Bulletin of the Torrey Botanical Club for November last, 
Ashe in the first part of the current volume of the Journal of the 
Elisha Mitchell Scientific Society, and Kraemer in the American Journal 
of Pharmacy for March. In commenting on some of these papers in 
the Journal of Botany for March, James Britten and Edmund Baker 
analyze the synonymy of certain of the species and call rather em- 
phatic attention to the desirability of consulting types in serious sys- 
tematic work. Some slight bibliographic confusion is likely to result 
from the publication of Mr. Ashe’s paper in separate form long enough 
before the number of the Journal containing it was issued to enable 
him to revise the latter into quite a different article. oo 
Combs’s Flora of Santa Clara Province, Cuba. — The island of 
Cuba is one of considerable interest to the botanist, as is shown by 
the rich collections made by many early explorers. In recent years, 
however, the region seems to have been neglected. We have before 
us a contribution of considerable length devoted to the flora of 
Cienfuegos, province of Santa Clara, by Robert Combs.’ The 
author enumerates 713 species, of which Caesalpinia cubensis, Acacia 
1 Plants Collected in the District of Cienfuegos, Province of Santa Clara, Cuba, 
in 1895-1896. Zrans. Acad. Sci. of St. Louis, 7: 393-491, pls. 30-39, one map, 
1897. (Contributions Botanical Department, Iowa State College of Agric. and 
Mechanic Arts, No. 7.) 
