102 BOTANICAL GAZETTE | FEBRUARY 
Chetophora calcarea Tilden, Am. Alg. Cent. I. no. 11. 1894 
(pl. VII. and pl. IX., figs. 6-7) —Thalli globose, subglobose, 
or confluent into ridges, encrusted with lime. Lower cells 
gv in diameter, 3~5 times as long; upper cells 8—12.5¢ in diam- 
eter, two times as long; articulations distinctly contracted at 
joints; terminal cells usually rather blunt, sometimes ending in 
very long articulated sete. 
The presence of lime in the thallus has been employed as a varietal char- 
acter in the genus Chetophora in two instances, viz.: Chetophora cornu-dam@ 
(Roth) Ag. var. crystallophora Kg. and var. incrustans Rabenh. An exam- 
ination of herbarium material comprised under eight species indicates the 
presence of lime in quantity in twenty-seven out of forty-five cases. Eigh- 
teen specimens show no trace of the substance. Out of twenty specimens of 
C. cornu-dame, ten showed strong indications of lime, four of these being of 
the var. crystallophora, and two being of the var. clavata. Eight out of the 
nine specimens of C. ¢uberculosa were encrusted with lime. 
Kjellman’s specimen from the polar sea, C. Jeflicula, said to form a crust 
200-300 in thickness, is in all probability a lime secreting plant 
C. calcarea and a plant nearly related to this genus, Stigeoclonium fia- 
gelliferum Kg. (Pilinia diluta Wood), both studied in this laboratory, possess 
the capacity of secreting lime to a remarkable degree. In both the calcium 
carbonate is deposited in the form of crystal plates, which are penetrated by 
the filaments and branches of the plant. 
Taking these facts into account, it would seem that the presence or 
absence of lime in Chetophora thalli should be regarded as a factor in the 
determination of the species. 
CHANTRANSIA PyYGMHA (Kg.) Sirodot, Les Batrachospermes 
244, 245. 1884. Am. Alg. Cent. II. no. 112. 1896 (pl. 7X, 
fig. 8) Stratum very thin, when dry forming a violet-colored 
calcareous crust on lower shaded surface of dead twigs. Fila- 
ments straight; branches erect, sometimes appressed to stem, 
apices somewhat attenuate; articulations 11-12» in diameter, in 
general 2-3 times the diameter in length; branches bearing 
sporules short, situated in upper portion of the plant; sporules 
in general 2-3 upon a branch. 
_ The description of the asexual form of p Dn eee crouanianum, 
as given by Sirodot, seems to cover fairly well the characters of the above - 
plant. But, so far as is known, the capacity for secreting lime has not 
_ hitherto been same: in connection with this ; — 
