— 8o— 



of Mnium punctatum. In Dicranum scoparium the dorsal protuberances are 

 formed by the swelling of dorsal cells. In Catharinea undulatum the margin of 

 the leaf in cross-section consists of 4 cells. In the 2-cell stage the dorsal and 

 ventral cell each divides by an anticlinal wall, perpendicular to the surface of 

 the leaf. The leaf margin is not comparable to the midrib. In Barhula ruralis 

 two-thirds the length of a young leaf measuring .05 mm. is the hair point which 

 in cross section is more or less a quadrant of cells. The greatest development 

 of the hair point takes place at the beginning of leaf development. In the cross- 

 section of a Leiicohryum glaucum leaf a green cell situated more to the dorsal side 

 than the other chlorophyll cells marks the plane of symmetry of the leaf. 



The apex and the margin of moss leaves are differentiated first. The process 

 of cell division in moss leaves is transferred from the apex to the base during 

 the progress of development. 



W. H. Emig, 



University of Pittsburgh 



DUPLICATE SPECIMENS FOR EXCHANGE 



Among Members of the Sullivant Moss Society only. Return postage, 

 rather than a stamped envelope, should be sent with the request for specimens: 



Dr. W. H. Emig, Dept. Botany, University of Pittsburgh, Pittsburgh, Pa. — 

 Plagiochasma Wrightii Sull., collected by W. H. Emig, on travertine, Price's 

 Falls, Arbuckle Mts., Okla. {See The Bryologist 20: 17, March, 1917). 



Dr. John W. Bailey, 4541 Fourteenth Ave., N. E., Seattle, Wash. — Gymno- 

 mitrium ohlusum (Lind.) Pears., Cascade Mts., Snohomish Co., Wash. 



Miss Daisy J. Levy, 403 West 115th St., New York City. — Sphagnum magel- 

 lanicum Brid., collected at Farmingdale, N. J., by Miss Daisy J. Levy. 



Mr. D. Lewis Dutton, Brandon, Vermont. — Anthoceros laevis L., Umhili- 

 caria pustulata var. papulosa (Ach.) Tuck., and Sphagnum suhsecundum Nees. 



Miss Helen E. Greenwood, 12 Hudson St., Worcester, Mass. — Odontochisma 

 denudatum (Mart.) Dum., collected near State College, Pennsylvania, and 0. 

 prostratum (Sw.) Trev., c9llected near West Barrington, R. I., both by Miss 

 Helen E. Greenwood. 



A CORRECTION 



While noticing for The Bryologist the second list of Additions to the Flore 

 des Mousses de la Suisse, published by Dr. J. Amann, I regret to have made an 

 awkward error. In the tenth line from the foot of page 29 (Volume 24. 192 1.) 

 the statement should read number of cells per square millimeter, and not "linear' 

 as printed. 



Edward B. Chamberlain 



