322 
Prof. Underwood referred to the influence of the Gulf Stream 
in permitting the occurrence of the subtropical genus Leyewnia on 
the coast of Ireland, a genus not elsewhere found in Europe. 
Comparing the Hepaticae of Florida, they are only in part known ; 
a few species are in common with the Appalachian flora; most of 
the Florida hepatica are close-creeping forms found on bark, as 
Frullania and Lejeunia, having water sacs on their leaves as aids in 
resisting drought. Some tropical Marchantiaceae occur in Florida, 
and also, especially, species of Azccia and Anthoceros. Thallocar- 
pus is known only from Florida and South Carolina. 
Index to recent Literature relating to American Botany. 
Atkinson, G. F. The Preparation of Material for general Class Use. 
Bot. Gaz. 23: 372-376. 21 My. 1897. 
Beal, W.J. Bromus secalinus germinating on Ice. Bot. Gaz. 23: 
204. 24 Mr. 1897. 
Britton, E.G. Emily L. Gregory. Bull. Torr. Bot. Club, 24: 221- 
228. fortrait. 29 My. 1897. 
Britton, N. L. The Metric System and the ‘Illustrated Flora.” 
Bot. Gaz. 23: 204, 205. 24 Mr. 1897. 
Burnap, C.E. Contributions from the Cryptogamic Laboratory of 
Harvard University—XXXVII. Notes on the genus Calostoma. 
Bot. Gaz. 23: 180-191. p/. 79. 24 Mr. 1897. 
Three American species are recognized, 
Burnett, K. C. Notes on the Influence of Light on certain dorsiven- 
tral Organs. Bull. Torr. Bot. Club, 24: 116-122. pl. 297. 30 
Mr, 1897. 
Calkins, G. N. Chromatin-reduction and Tetrad-formation in Pteri- 
dophytes. Bull. Torr. Bot. Club, 24: ro1—-115. pi. 295, 296. 30 
Mr. 1897. 
Chamberlain, C.J. Contribution to the Life-history of Sa/x. Bot. 
Gaz. 23: 147-179. pl. 72-18. 24 Mr. 1897. 
Coville, F. V. Bibliography of Aypoxis. Bot. Gaz. 23: 206. 24 
Mr, 1897. 
