CONTENTS 
STEINBERG, R.A. As study of some factors influencing the stimulative action of 
ie 



zinc sulphate on the growth of Aspergillus niger— A comparison of 
tWo Slrains Of fue tite ie (pate 2) i Gs ig Ge ae Se a ¥ 
Wituiiams, R. S. Notes on some western Lichens.............-..-e-ceceeee 21 
Brown, ELIZABETH DOROTHY WUIST. Apogamy i in Camptosorus rhizophyllus 
ie Pee ee, GOL 6A I EE ee Ch er ay 27 
RAMALEY, FRANC ds at diff Ititud Colorado 37 
OSTERHOUT Sas. 7 ‘Additions vi the flora: ot Colorada. a Oe: Sz 
Levine, MicuareL. The sporadic a ulate of non-edible mushrooms in 
cultures of Agaricus campestris (plates 3-5)... 0270 oe ee. 57 
WEATHERWAX, PAUL. Gametogenesis sal fecundation in Zea Mays as the 
basis of xenia and heredity in the endosperm (plates 6, 7).........-..+0.005 43 
ANDREWS, F. M., and Brats, C. C. The effect is soaking in water and of 
Seration-an tie growth Of Zea Mavs. ie ee pcb ee eee eS or 
ARTHUR, JOSEPH CHARLES. News Ale OF Uredinede-—KEs oa ee 107 
Brown, Forest B. H. The preparation and treatment of woods for micro- 
es ie ee ee ei es ev bcc Cw eb bede ave 127 
STEWART, E.GrRaAcE. Mucilage or slime formation in the cacti (plate 8)........ 157 
Evans, ALEXANDER W. A taxonomic study of Dumortiera........../...... 167 
PENNELL, FRANCIS W. Notes on plants of the southern aoa States—V.. 183 
GRIFFITHS, Davip. New and old species of Opuntia (plates 9, 10)........... 195 
Wi111aMs, R.S. The genus Desmatodon in North America (plate 11)....... 207 
ASHE, W. W. Notes on trees and shrubs in the vicinity of Washington....... 22% 
GLEASON, HENRY ALLAN. Taxonomic studies in Vernonia and related gene 235 
Recorp, SAMUEL J. Storied or tier-like structure of certain dicotyledonous 
NI ee ens ie i ee a ak ae et eae 253 
WEATHERWAX, Paut. The ancestry of maize—a reply to criticism.......... 275 
Berry, Epwarp W. A new Matonidium from Colorado, with remarks on the 
distribution of the Matoniaceae (plates 12; 13)... 2... 2... eee ee ee 285 
RypsBerc, P. A. Phytogeographical notes on the Rocky Mountain region— 
VIII. Distribution 7 the Montane poe NS angst Serer tne 1g? Sel Ata 295 
Cavace, MaArGARET B. The develop truct f the bulb in Cooperia 
Pirnmmondit (ties Ta-16) ae i a se nae ee ae 337 
PENNELL, FRANCIS W. A brief conspectus of the species of Kneiffia, with the 
characterization ob. a new allied Benus. {o65 ccyc eee iS ae eee 363 
Hitrcucock, Romyn. Preliminary note on a differential staining of the cyto- 
Aah ts CUA ACCRC Ss fi go eg Po ac es es Pie 5 ss i 375 
SMITH, CHARLES PIPER. Studies in the genus peg — Pua; ec; 389 
ARTHUR, J. C., and Mains, E. B. Grass rusts of unusual structure.......... 4it 
BICKNELL, EUGENE P. The ferns and flowering plants of ae! 423 
Tuurston, H. W., Jr. Sex in the Conjugatae and the relative frequency of 
the difteress) types of COMpUSALION... . oo rs eee so a ee ees 441 

