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RHACOPILUM TOMENTOSUM (Sw.) BR1D. 
Elizabeth G. Britton. 
This genus and species are not recorded within the limits of the United 
States in Lesquereux and James’ Manual, though Rau and Hervey listed 
them in their catalogue of 1880. Specimens were first collected at Donaldson- 
ville, Louisiana, by Dr. Charles Mohr in November, 1856, and named for him 
by Dr. Carl Muller, who indicated its wide tropical and subtropical distribution. 
This species was described as Hypnurn by Swartz in 1788 and the type local- 
ity was Hispaniola, presumably from the western part of Haiti or Santo 
Domingo. 
Scraps of the type material have been examined at Kew and the British 
Museum, and a duplicate West Indian specimen from Swartz has beenTound 
in the Mitten Herbarium. Drawings have been made by Miss Taylor from 
one of these co-types and from the specimens collected by Dr. Charles Mohr 
in Louisiana for the accompanying plate. 
My first acquaintance with this species was made in Bermuda in Septem- 
ber, 1905, where it was found in great abundance in Church Cave, growingon 
damp rocks in shade and fruiting. Since then it has been found in Jamaica, 
and all the West Indian and Central American specimens have been care- 
fully studied and compared. This seemed imperative for the names, syno- 
nyms and varieties given by Paris Index Ed. 2. 4: 164. 1905, indicated that 
there was a mixture and very wide distribution with considerable variation. 
The synonymy of the North American species is as follows: 
Rhacopilum tomeiitosum (Sw.) Brid. Bryol. univ. 2:719. 1827. 
Hypnum tomentosum Sw. Prod. FI. Ind. occid. 141. 1788. 
Hypnurn tomentosum Hedw. Muse, frond. 4: 48, t. 19. 1797. 
Plants dark green: stem creeping, branching and tomentose with brown 
radicles: branches erect; leaves curled and twisted when dry, the upper 
smaller than the lower; lower leaves 1-2 mm. long by half as broad, vein 
excurrent with a subulate awn, upper leaves fewer, smaller with points 
nearly as long as the blade: margins more or less coarsely and unevenly ser- 
rate above the middle; cells hexagonal, basal oblong, slightly decurrent, 
median cells o 008-0.017 mm. X 6.008-0.012 mm., inflated or slightly mamil- 
lose, occasionally minutely papillose. Monoicous, perichaetial leaves smaller 
and long-subulate. Seta 2-3 cm. long, stout and red; calyptra 2 mm. long, 
cucullate and hairy; lid conic-rostrate, annulus simple, falling with the lid, 
neck slightly strumose; capsule curved, 5 mm. long, walls ribbed when dry, 
with 4-10 rows of quadrate collenchymatic cells alternating with narrower, 
longer parenchymatic cells; peristome double; teeth brown with paler papil- 
lose tips; endostome white and papillose, carinate segments split; cilia 
appendiculate and papillose: spores green, 0.013-0.016 mm., smooth. 
On decaying trunks of trees in deep woods and Cypress swamps. On the 
shore at the Bay of Bayou Lafourche, Donaldsonville, Louisiana, Chas. 
Mohr. November and December, 1856. 
Type locality: “Hispaniola,” O. Swartz. “On roots of trees near 
