10S The Scottish Naturalist. 



cens vel sordide flavescens, apicibus ramulorum et fibrillarum 

 nigricantibus, stipitibus et ramis papilloso-asperrimis seque 

 ac receptaculis apotheciorum ; axis centralis gracilis. 



Prope Darjeeling (Himalaya), J. Thomson. 



Usnea subfusca sp. nov. — Similis U. floridcx sed stipitibus et 

 ramis primariis papilloso-asperis, axi centrali crasso solido 

 rufescente, centro rufo-fusco. Thallus extus K — C pallide 

 flavescens. 



Prope Owen Sound in Canada (Mrs Roy). 



Of U Icevis (Eschw.) I possess one specimen from the 

 Brazils (Mr Weir), whose characters correspond sufficiently 

 with those described by Nylander in his Synopsis. 

 Fibrillse medullares K fl. dein rubentes ; thallus extus K flavens. 



Usnea cavernosa (Tuck.) has the medullary fibres K yellow. 



I possess only one specimen of an Usnea from South Africa, 

 by Mr H. Bolus, which can be ranked with U angulata (Ach ) 

 It is a robust species. At the bifurcations the thallus assumes 

 the form of broad flat plates (breadth from 1-2.5 mm.), while the 

 plate-like form is also seen throughout the main stems, and so 

 disposed as often to give them a triangular appearance in 

 section. The central axis is thick, dense, and solid, nearly as 

 in U longissima, but I — ; medullary fibres white, forming a 

 thin layer surrounding the axis K — C — , I — ; apothecia 

 large, latitude often as much as 15 mm. Meanwhile this may 

 be ranked as a sub-species of U. angulata, under the name Usnea 

 goniodes. 



Addendum. 



The Usnea which, in Scotland at least, has most frequently 

 the reactions, fibrillar medullares K flaventes, I violascentes, is 

 that which has the branchings most nearly allied to what I have 

 defined under U hirta. Casually looked at, specimens of this, 

 loosely huddled together, give the impression of Hypnum 

 taniariscinum. This may be called Usnea subpectinata. Thallus 

 pallide cinereo-glaucescens vel pallide cinerascens. 



Amongst my Scottish collections there is a fair sprinkling of 

 another form, whose reactions argue in favour of a place near U 

 articulate but whose stems are erect and not smooth, but here 

 and there slightly rough. 



