256 BOTANICAL GAZETTE : [MARCH 
is due to the high osmotic pressure. It is suggested that in these plants absorp- 
tion by aerial organs (involving both sea water and atmospheric water) may 
in nature supplement root a although the latter doubtless is the more 
important.—H. C. Cow 
Xerophytic fern prothallia.—The very delicate character of fern prothallia 
in general and their usual development under humid conditions have made it 
cult to account for the establishment of various ferns in dry, rocky situa- 
tions. Some light has recently been shed upon the subject by experi 
cultures of the prothallia of Camptosorus rhizophyllus by Pickett.% Exposed 
to conditions of desiccation arranged to simulate as far as possible ‘those of dry 
limestone ledges under conditions of natural drought, the prothallia showed 
complete recovery after 34 days, and 25 per cent recovery after 55 days. 
Under rather more rigorous conditions, only 50 per cent of the prothallia died 
after 38 days’ exposure to conditions of drought that killed all the prothallia of 
Onoclea Struthiopteris in 48 hours; while under the most rigorous aridity in @ 
sulphuric acid desiccator a small proportion of the prothallia survived 4 days’ 
exposure. All these tests go to prove that the drought-resisting character of 
the prothallia of Camptosorus must be a very important factor in the establish- _ 
ment of this fern in its characteristically xerophytic habitats —Gro. D, FULLER. 
Rhodophyceae of the Indian Ocean.—Mrs. WEBER VAN BOSSE” has 
reported upon a collection of Rhodophyceae made in 1905 on the Percy Sladen 
Trust Expedition to the Indian Ocean. The geographical distribution shows 
a great resemblance between the algal flora of the Indian Ocean and that of 
the Malay Archipelago, as well as that of the east coast of Africa. A table 
shows the locality, bottom, depth, and distribution of each of the 79 species 
collected, among which there are 18 new species, and a new genus (P. seude- 
nosiphonia) of Rhodemelaceae.—J. M. C. 
Plant — making 
recognizes 
Th 
groups as ‘disest Thallophytes 79,450, of which the Ascom 
Basidiomycetes include 64,000; Bryophytes 16,600; Pteridophytes 4,524; 
Gymnosperms 540; Angiosperms 132,500.—J. M. C. 
# PicKETT, F. L., Resistance of the prothallia of Campiosorus rhizophyllus to 
desiccation. Bull. Torr. Bot. Club. 40:641-645. 191 
27 WEBER VAN Bosse, Mrs. A., Marine algae, chotenhiecai of the ‘“Sealark” 
expedition, collected by Mr. J. STANLEY Garnier. Trans. Linn. Soc. London ei 
II. 8:105-142. pls. 12-14. 1913. 
% Bessey, CHARLES E., Revisions of some plant phyla. 
73. 1914. Lincoln, Nebraska. 
Univ. Studies 14" 
