ERR] Botany. 569 
BOTANY. 
Cæoma nitens.—The development of Cwoma nitens has recently 
been studied by Mr. H. M. Richards, and the results published in an 
interesting paper in the Proceedings of the American Academy .of 
rts and Sciences, The particular question investigated was whether 
or not the spermogonia are developed within the cavities of the 
epidermal cells of the host. By means of carefully made sections, Mr. 
Richards demonstrates that they arise as masses of hyphæ which push 
up between the epidermal cells, and that later the walls of some of these 
cells become absorbed. The spermogonia are therefore at first inter- 
cellular, but by the absorption of the walls they become intracellular. 
CHARLES E. BESSEY, 
Our Naiads.—Thomas Morong’s monograph “The Naiadacex of 
North America ” has been brought out in the Memoirs of the Torrey 
Botanical Club. It contains descriptions and plates of 54 species 
distributed as follows: Triglochin, 3 species; Scheuchzeria, 1; Lilea, 
1; Potamogeton, 37 ; Ruppia, 2; Zannichellia, 1; Naias, 4; Zostera, 
3; Phyllospadix, 2. Among these we find one new species Potamoge- 
ton faxonit from Lake Champlain, and several new varieties of pre- 
viously described species. Quite a number of changes have been made 
in the nomenclature of the species. vs 
Thus comparing Dr. Morong’s list with that in the 6th edition of 
Gray’s “ Manual,” we note the following changes: Potamogeton penn- 
sylvanicus Cham. and Sch. becomes P. nuttallii Cham. and Sch., since 
the latter was described on an earlier page of Linnea than the former 
(II. 1827) ; P. hybridus Mx. (1803) being preoccupied (by Thuillier 
in 1790), gives way to P. diversifolius Raf. (1808) ; P. rufescens Schrad. 
(1815) is antedated by P. alpinus Balbis (1804) ; P. fluitans Roth. 
(1788), gives way to P. lonchites Tuck. (1848), inasmuch as it is 
highly improbable that the European and American species are 
identical ; P. zizii Mert. and Koch. of the “ Manual” appears to have 
included two species which are now to be known as P. thulaformis 
(Robbins) Morong, (P. gramineus, var. (?) spathulaformis Robbins, P. 
spatheformis Tuck., and P. varians Morong), and P. angustifolius 
Berch. and Presl. (P. lucens, var. minor Nolte); the var. lanceolatus 
Robbins (1867) of P. perfoliatus L. being preoccupied by Blytt (1861) 
- Must give way to var. richardsonii Ar. Bennett (1889) ; P. pauciflorus 
Pursh. (1814) must be replaced by P. foliosus Raf. (1808) ; P. mueron- 
