26 BOTANICAL RESULTS OF THE SCOTTISH NATIONAL ANTARCTIC EXPEDITION. 



USNEA MELAXANTHA, Ach., is common both in the Arctic and Antarctic regions of 

 America and Europe, and also in New Zealand and the Andes. A number of species 

 appear to be -nearly related to this plant, but they are not all quite clearly defined. 

 I am referring to U. Taylori (Hook.) ; U. Hieronymi, Krphbr. ; U. trachycarpa, Miill.- 

 Arg. ; aiid even U. sulphured, Konig, which is probably only a synonym of U. melax- 

 antha, Ach. Some of the specimens were found growing on and firmly attached to 

 Gyrophora rellea. 



BRYOPOGON JUBATUM, Link. Cosmopolitan, Arctic, and typically Alpine. Small 

 plants were found in between specimens of Usnea melaxantha from the South Orkneys. 



RINODINA TURFACEA ( Wahlenb.), Fr. Europe, Asia, and America, Alpine and Arctic. 

 The material collected from a rock on the South Orkneys must, I think, be included in 

 this species. It has a remarkably well-developed, thick thallus, but this may be due 

 to its unusual habitat on rocks. 



PLACODIUM ELEGANS (Ach.), Nyl. -Cosmopolitan, Arctic, and typically Alpine. 

 Good fertile specimens were found on rocks on the south-west shore of Scotia Bay, 

 South Orkneys. 



PLACODIUM REGALE, Wainio ( = Placed ium fruticulosum, Darbish., Trans, and Proc. 

 Bot. Soc. Edin., xxiii. 1. (1905) *). Thallus fruticulosus, basi substrato affixus. 

 Protothallus gonidiis destitutus, chondroideus, margo effusus et hyphis instructus 

 solitariis vel conglutinatis. Podetia fruticulosa, ad marginem thalli prostrata et leviter 

 compressa, inferne albida, nondum substrato affixa nisi protothallo ; ad centrum thalli 

 erecta, 1-2 cm. alta, dichotome sed irregulariter divisa, 1-1 '5 mm. crassa, ad apices 

 bene divisa; apices juxtapositi thallum crustaceum simulantes ; aurantiaca aut flaves- 

 centia, KHO purpurascentia ; stratum corticale hyphis instructum transversalibus, 

 cuticulo valde distincto obtectum 6-8 M lato ; stratum medullare dense strupeum. 

 Gonidia protococcoidea. Apothecia lecanorina, 1-4 mm. lata, emergentia, sed adpressa, 

 lateralia; amphithccium distinctum, gonidiis instructum; parathecium decoloratum ; 

 epithecium flavescens aut aurantiacum, KHO purpurascens ; hypothecium decoloratum, 

 strato gonidiali inferne instructum; thecium 90-100 M crassum ; paraphyses simplices, 

 apice cellulis brevibus terminantes ; axi cylindrici, elevati 10 M lati ; sporse octonae 

 hyalinae bicellulares orculiformes, 5-6xll'5 M magnse. Spermogonia et soralia non 

 visa. Habitat ad saxa, S. Orkneys. 



Placodium regale was found growing on rocks around Scotia Bay, South Orkneys. 

 It is apparently very common from the shore right up to the summit, evidently repre- 

 senting an important constituent of the lichen vegetation. The podetia are fruticulose 

 and erect, branching frequently and in an irregular way. The tips of the branches, 

 however, are pretty much of the same height, and being very closely applied to one 



1 This species was described independently by M. Wainio and Dr Darbishire from the Belgica and Scotia collections. 

 -B. N. B. B. 



