The Scottish Naturalist. 10 



o 



Neuropogon trachycarpus (Strn.) — Similis N. melaxantho sed 



receptaculo apotheciorum fibrilloso - ciliato et papilloso- 

 rugoso ; fibrillar merlullares K — ; axis centralis gracilis 

 et fibrillar medullares arachnoideae, I — . 



Kerguelen's Land (Challenger Expedition). 



The central axis in N. melaxanthus is thick, and the medul- 

 lary fibres rather compact. I have a vague recollection that K 

 gives a negative reaction on the medullary fibres of a specimen 

 of N. melaxanthus from Greenland; but I cannot at present cor- 

 roborate this statement, as the specimen is not now in my 

 possession. 



Neuropogon Taylori (Hook.) has reactions — viz., thallus intus 

 K— C— , extus K— C fl. 



Usnea dasypoga (Fr.) — In a specimen of this from Peak's Island, 

 Maine, North America, I find the central axis thick, solid, 

 the medullary fibres compressed, and the reactions K — , I — . 



There is another resembling this from Niagara Falls (Mrs 

 Hawley, 1879) viz. — 



Usnea variegata sp. nov. — Thallus cinereo-glaucescens, cinereo- 

 virescens vel cinereus, gracilis, elongatus, pendulus, fibril- 

 losus ; axis centralis fusco-rufescens (praesertim stipitum) 

 crassiusculus ; fibrillar medullares (K — vel vix tinctas), eae 

 axin tegentes I caerulescentes dein violaceas. 



Usnea longiss'una (Ach.) is constant in its chemical reactions — 

 viz., the thick corneous central axis is, without and within, 

 blue, or a sordid blue, with Iodine. The medullary fibres 

 are scarcely discernible, as the axis occupies nearly the 

 whole stem, being merely covered by the thin cortical layer. 

 Where perceptible, these fibres are scarcely, if at all, tinted 

 yellow by K. In the great majority of cases the axis is of 

 a pale colour, merging, though rarely, to rufescent. 



In one specimen from the Himalayas (No. 17 18, Hooker and 

 Thomson) the axis is a brownish or violaceous black colour, and 

 it gives a negative reaction with I. This lichen is also much 

 more robust than usual, and has a crisped appearance. To this 

 I propose giving the name Usnea mekista. It certainly deserves 

 the rank of a sub-species. 



Another Usnea, common apparently in South Africa (Professor 



