I 
CONTENTS. 
No. XCVII, January, 1911. 
PAGE 
Oliver, F. W., and Salisbury, E. J. — On the Structure and Affinities of the Palaeozoic 
Seeds of the Conostoma Group. With Plates I— III and thirteen Figures in the 
Text i 
Lee, E. — The Morphology of Leaf-fall. With Plates IV-VI and twenty Figures in the Text 51 
Butler, O. — A Study on Gummosis of Prunus and Citrus, with Observations on Squamosis 
and Exanthema of the Citrus. With Plates VII-X and three Figures in the Text . 107 
Brenchley, W. E. — The Weeds of Arable Land in relation to the Soils on which they 
grow 155 
Sinnott, E. W. — The Evolution of the Filicinean Leaf-trace. With Plate XI and eleven 
Figures in the Text. ............ 167 
Berry, E. W. — A Lower Cretaceous Species of Schizaeaceae from Eastern North America. 
With Plate XII and one Figure in the Text 193 
Beer, R. — Studies in Spore Development. With Plate XIII 199 
Fames, A. J. — On the Origin of the Herbaceous Type in the Angiosperms. With Plate XIV 215 
Bailey, I. W. — The Relation of the Leaf-trace to the Formation of Compound Rays in the 
Lower Dicotyledons. With Plates XV-XVII and one Figure in the Text . . 225 
Carruthers, D. — Contributions to the .Cytology of Helvclla crispa, Fries. With Plates 
XVIII and XIX . 243 
Prankerd, T. L. — On the Structure and Biology of the Genus Hottonia. With Plates XX 
and XXI and seven Figures in the Text 253 
NOTES. 
Stopes, M. C. — A Reply to Prof. Jeffrey’s Article on Yezonia and Cryptomeriopsis . . 269 
Schwartz, E. J. — A New Parasitic Fungus found in the Roots of Grasses. — Preliminary 
Notice 270 
Osborn, T. G. B. — A Preliminary Note on the Life-history and Cytology of Spongospora 
subterranea, Wallroth . . . . . . . . . . . .271 
Horne, A. S. — Preliminary Note on Spongospora Solani, Brunch. . . . . .272 
Bentley, B. H. — An Arrangement for using the Blades of Safety Razors in the Microtome. 
With three Figures in the Text .273 
No. XCVIIX, April, 1911. 
Bower, F. O. — Notes on the Morphology of Ophioglossum (Cheiroglossa) palmatum, L. 
With Plates XXII-XX 1 V . ■ 277 
Woodburn, W. L. — Spermatogenesis in certain Hepaticae. With Plate XXV . . . 299 
Bailey, I. W. — A Cretaceous Pityoxylon with Marginal Tracheides. With Plate XXVI . 315 
Osborn, T. G. B. — Spongospora subterranea, (Wallroth) Johnson. With Plate XXVII . 327 
Essed, E. — The Panama Disease. I. With Plate XXVIII 343 
Essed, E. — The Panama Disease. II. With Plate XXIX 353 
Essed, E. — The Surinam Disease. A Condition of Elephantiasis of the Banana caused by 
Ustilaginoidella oedipigera. With Plate XXX ....... 363 
Essed, E. — Rice Disease caused by Ustilaginoidella graminicola. With Plate XXXI . . 367 
