390 BOTANICAL GAZETTE [May 
spherical mass of cells gives rise to two opposite and distinct cotyledons, 
with the plumule between them. Later the cotyledons become hemispheri- 
cal and concave, applied against each other all round by the edges, and 
enclosing a central cavity occupied by the plumule. This seems to indicate 
that the embryo of Nelumbo must be regarded as dicotyledonous and unsym- 
metrical, rather than monocotyledonous with a two-lobed cotyledon.—J. M.C, 
GeorGE H. SHULL has made a quantitative study of variation in the 
bracts, rays, and disk florets of certain species of Aster. His conclusions 
are that there is a close correlation between bracts and rays, arising from the 
fact that the rays are axillary to the bracts; that the degree of imbrication 
of the bracts bears a relation to the number of empty bracts; that in a single 
group of specimens of A. prenanthoides the number of bracts, rays, and disk 
florets decreases continuously from the beginning to the end of the flowering — 
season ; and that the character of the curves and the position of their means 
and modes likewise change continuously. Curves and constants were deter- 
_ mined for the material studied; and constants determined for several indi- 
viduals of A. punicus, growing in identical surroundings, indicated how great 
Variations may exist in the variability constants of individuals.—]. M.C. 
__1N HIS THIRD PAPER® on-American ferns, Professor Underwood discusses : 
the order of their relative importance, are (1) type of venation, (2) eae 
5 sity ‘oft ‘some erection for anchoring ginece names. ~ 
can genera of Aspidieae, only three of which are pee the 
tates, are recognized as follows: Leptogramma J. Sm., Phegoper® 
cosorus Fée, Polystichum Roth., Cyclopeltis J. Sm., Didymoe 
Jesv., | Camptodium Fée, Dryopteris Adans., Phanerophilebia’ J 
teris Presl, Meniscium Schreb., Cyclosorus Link, Fadyenia Hook. 
e ectaria Cav., and Sagenia Presl.— J. M.C 
ANOTHER PAPER proving that the ae mother cell of Ascleplas 
: tise to four “microspores has just appeared.” baauosaay a and Fi S 
244 quantitative study of variation in the bracts, rays, and d Yel 
Shortt, A. Novae-Angliae, a a and A. prenanthoides, from 
Ohio. Amer. Nat. 36: 111-152. 1902 
S oe 5 Bull, ‘Tor. Bot. Club 29 : 121-136. ac 
: the genera of Aspidieae. The any yee he sakes in - 
*°Gacer, C. S., The ce gT of the pp aninae and — beets. 
p17 F 
aman of eed ee 123-148. fi. 
"Deon of the eps in some Ascendant 
