I 58 
A marginal cell on the shed leaves of R. obconica darkens, enlarges, and the 
cell-wall thickens, though not as noticeably as in Frullania. This enlarged 
cell divided by a horizontal wall, forming an inner and an outer cell. The outer 
one divides by a wall perpendicular to the leaf-margin, these divide in turn, 
and one side cuts out a triangular apical cell. The shoot develops directly 
from this, its first leaves being rudimentary, but it soon forms regular leaves 
with lobules, and is then easily detached from the parent leaf. 
The cell-masses are not produced in as great abundance as in Frullania , 
but were observed on perhaps half of the specimens studied. They occur upon 
$ bracts as well as upon the leaves; none were observed upon the lobules. 
The habitat has no apparent effect upon the production of brood-leaves, 
for while all the New England material examined by the writer grew on rocks, 
some particularly fine specimens were found on Miss Biddlecome’s Ohio plants 
growing upon Juniperus. 
The accompanying figures are drawn mainly from material collected by 
Dr. Evans in Connecticut, and the writer would thank him for lending his mate- 
rial of R. obconica for these investigations. 
Hartford, Connecticut, March, 1918. 
LITERATURE CITED 
1 . Goebel, K. — Organographie der Pflanzen. 
Zweiter Teil, erste Heft. Bryophyten. p. 674. 1915. 
2 . Lorenz, A. — Vegetative Reproduction in the New England Frullaniae. Bull. Torrey 
Club 39 : 279-284, f. 1-3. 1912. 
3 . Miiller, K. — Lebermoose, in Rabenhorst. Kryptogamen-Flora Deutschlands, &c. 62 : 
539 - 553 - 1915 . 
4 . Stephani, F. — Species Hepaticariim. Vol. 4, p. 216, 1910. 
5 . Stevens, N. E. — Discoid Gemmae in the Leafy Hepaticae of New England, Bull. Torrey 
Club 37 : 365-373. f- i- 4 - 1910. 
6. Sullivant, W. S. — Gray’s Manual, Ed. 1, 1848. 
7 . Underwood, L. M. — Descriptive Catalogue of the North American Hepaticae North of 
Mexico. Bull. Illinois State Lab. Nat. Hist. 2 : 1-133. 1884. 
8. Underwood, L. M. — In Gray’s Manual, Ed. 6, p. 708, 1889. 
9 . Williston, R. — Discoid Gemmae in Radula. 
Bull. Torrey Club 39 : 329~339- f- i~37- 1912. 
PLATE XXV. EXPLANATION OF FIGURES 
Radula obconica Sullivant 
1. Plant with perianth. X22.K 
2. Plant with perianth. X22K 
3. Sterile shoot. X22.K- 
4. Sterile bract. X43K- 
5. Sterile bract. X 43 K* 
6. Leaf-cells. X285. 
All figures drawn by the writer from material from Mt. Carmel. Branford and N. Stoning- 
ton, Conn. (A. W. E.), and Mt. Washington, Mass. (A. L.). 
7. Marginal cells. X285. 
8 . Leaf with cell-masses. X43X. 
9. Leaf with cell-masses. X43K. 
10. Leafy shoot. X 43 M- 
11. Leafy shoot. X43K. 
