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less, porous cells in the leaves and frequently also in the stem and branches; 
(2) the close overlapping of the leaves on the branches; (3) the sponge-like mat- 
ting of the pendent branches around the stem. 
Sphagnum moss was officially adopted by the American Red Cross as a 
standard surgical dressing material early in March of this year, but the enter- 
prise here has not yet attained the magnitude which it is reasonable to expect 
that it will in the near future. For one thing, the project here is comparatively 
new and our American army surgeons, accustomed to using absorbent cotton, 
seem reluctant to adopt the substitute, notwithstanding that its superiority 
has been conclusively demonstrated. But another very serious handicap to 
the sphagnum enterprise in this country is the lack of exact knowledge regarding 
our resources of surgical sphagnum. In the Pacific Northwest, largely through 
the efforts of Professor Hotson and his associates, the situation is now well in 
hand; but in the east, while we know in a general way that the material is here, 
we have all too few exact data regarding sources of supply. It is primarily 
with the object of eliciting information on this subject from bryologists, who 
of all people should be best qualified to furnish it, that the present article is 
written. The writer is associated with the Department of Development of 
the American Red Cross in the capacity of Botanical Adviser on Sphagnum 
and will be pleased to examine any specimens of material which may be sub- 
mitted. 
For the benefit of those who may be willing to cooperate, it should be em- 
phasized that there is a great difference in different lots of sphagnum when it 
comes to the selection of material for use in surgical dressings. First of all, 
different species differ greatly in their capacity for absorption, degree of softness, 
etc. Thus, of the forty species of sphagnum native to North America, only 
those belonging to the Inophloea group (the group which includes A. papillosum , 
S. palustre, S. imbricatum, S. magellanicum , etc.) have been found wholly satis- 
factory. Species of the Compactum group (S. compactum, S. strictum ) have 
not been tried out, but ought to furnish excellent material. S. squarrosum seems 
excellent as to foliage and probably is open to objection only on account of its 
usually wiry stem. The species in the remaining groups, comprising about 
three-quarters of our native sphagnum flora, are virtually useless for surgical 
purposes, although some of them may be employed to a limited extent for special 
purposes or in combination with material of the more suitable species. 
Speaking in general, it can be said that the more robust species of sphagnum 
are superior to the more delicate; forms with large leaves, dense foliage and 
close-set branches are greatly preferable to those with small leaves, skimpy 
foliage and scattered branches. Harsh, stiff, or brittle forms must be avoided. 
In this connection it should be further pointed out that not only is there a wide 
range of variation in the suitability of different species of sphagnum for surgical 
use, but in that of the same species from different regions or from different hab- 
itats within the same region. Thus, the average quality of material from the 
humid districts of western Washington and Vancouver is much higher than 
anything that has been seen from the east. In grading his western material, 
