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WHEN DOCTORS DISAGREE. 
Dr. Grout has recently printed the following- remarks on No. 196 of his 
North American Musci Pleurocarpi, which Cardot and Theriot have 
described in the May number of the Botanical Gazette as Plagiothecium 
Groutii. 
“No. 196. This is a most interesting form about which “ Doctors dis- 
agree ” very widely. Mrs. Britton has called it a variety of Plagiothecium 
denticti latum, but I do not believe many others will agree with her view. 
M. Cardot has named it as above. Dr. Best is sure it is a depauperate form of 
Raphidostegium recurvans. “ The perichaetial bracts, the pedical, the 
cilia, one or two, imperfect and shorter than the typical teeth, the imperfect 
annulus, the conical short-beaked operculum, about one-half the length of 
the urn and the quadrate-rectangular exothecial cells, are all about as we 
might expectin a starved form of R. recurvans-, “only this and nothing 
more.” Whatever else it may be it is not a Plagiothecium ! ” “I believe it 
is a new species which is more at home in Raphidostegium because of the 
enlarged alar cells in some of the larger plants. The smaller size, the 
shorter less slenderly acuminate leaves with alar cells much less strongly 
developed, complanate but not recurved and only very slightly unsym- 
metric, and the smaller capsules with shorter beak, seem to me so distinc- 
tive as to make this form worthy of specific rank. It hardly seems 
depauperate as it was growing with typical R. recurvans in a favorable spot 
(possibly a little dry at times) and besides it is fruiting freely. There is a 
little R. recurvans intertangled with it.” 
Now in this case there is every reason for disagreement because the 
specimens distributed as No. 196 were collected at Hempstead. Long Island, 
on December 1, 1899, and the specimens sent to me were collected at Law- 
rence, Long Island, May 25, 1899. I have recently examined No. 196, and 
am convinced that I have never seen these specimens before ! 
Furthermore they are mixed with Rhyne hostegium serrulatum not 
Raphidostegium recurvans , and the cells of the basal angles are not inflated 
and only slightly differentiated, two or three being rectangular instead of 
Ion g prosenchymatous like the rest of the leaf as figured by Theriot. There 
is no marked resemblance to any species of Raphidostegium , and it is 
incredible that Dr. Best should have mistaken it for a “depauperate form 
of R. recurvans ,” especially as Dr. Grout admits that this species was 
“intertangled” with it! I have just compared these two species and No. 
196 has the flattened unequaled leaves of Plagiothecium , and the apex 
though serrate is much shorter and broader and not strongly recurved as in 
R. recurvans! 
The description in the Botanical Gazette for May, p. 379, states that P. 
Groutii was collected in “Delaware: Hampstead ’’—this is also evidently a 
mistake according to Dr. Grout’s label ! The moral of this is that it is not 
worth while to print useless remarks about species that are mixed, nor to 
attribute wrong determinations of specimens which have never been sent! 
Elizabeth G. Britton, 
New York Botanical Garden. 
