Gyrophora.] LICHENBS. 155 



2. C. islandica, ACH. Thallus membranaceous, rigid, erect; 

 olive-brown, the segments entire, marginate, ciliated with stipi- 

 tate buds ; apothecia flat, the border narrow. Ach L. Un. p. 

 512. Eng. Bot. t. 1330. 



On the top of Mangerton. It grows more tufted in colder situa- 

 tions, than with us. The cilia are dark, often with a subrotund blacker 

 and wider top, which may be observed in certain states expanding into 

 new fronds. 



31. GYROPHORA, Ach. 



Thallus coriaceous or membranaceous, fixed by the centre. 

 Apothecia orbiculate, sessile, with the border of their own 

 substance, (not thallodal) the disk covered by a dark mem- 

 brane, usually rough with gyrose plaits. 



1. G. pustulata, ACH. Thallus coriaceous, with coarsely 

 pruinose pustules at the centre, laciniated or pertuse towards 

 the margin, greenish-grey ; buds granular dark- brown, near the 

 margin ; apothecia broadly marginate, the disk even or tubercu- 

 late. Ach. L. Un. p. 226. Eng. Bot. t. 1283. 



On rocks in the mountains ; not uncommon, but without apothecia. 

 The pustular appearance of the thallus is striking, but it likewise oc- 

 curs in a lesser degree in G. proboscidea, Ach. in G. vellea, Ach. and 

 even in some states of G. heteroidea, Ach. The degree of plication 

 of the disk of the apothecia likewise varies in this genus. So, in G. 

 vellea the disk is as in Lecidea ; in G. hirsuta, Ach. out of the cen- 

 tre of the disk (which is that of a Lecidea) often rises a single young 

 minute apothecium, sometimes two or more with margins gyrose by 

 mutual pressure. The buds may be observed expanding into new 

 fronds. 



2. G. erosa, ACH. Thallus coriaceous, rugged, dark-brown, 

 eroso-laciniated at the margin, beneath dark-grey, rough ; buds 

 granulate, rotundate, flattened at the top ; apothecia with the 

 gyrations on the disk grooved, the border nearly obliterated. 

 Ach. L. Un. p. 224. Eng. Bot. t. 2066. 



On Mangerton, on rocks ; and on other high mountains not uncom- 

 mon. 



3. G. cylindrica^ ACH. Thallus coriaceous, bluish or glau- 

 cous-grey, the segments subimbricate and ascending, ciliated 

 with flattish linear acuminate buds ; apothecia substipitate, the 

 gyrations on the disk grooved. Ach. L. Un. p. 223. Eng. Bot. 

 t. 522. 



On rocks at Connavalla, Dr. Whitley Stokes; on Mangerton. The 

 length of the cilia to the segments of the thallus is very remarkable ; 

 the cilia however appear to be truly buds, as their expansion into new 

 fronds may, with a little care, be observed. 



4. G. pellita, ACH. Thallus coriaceous, sinuato-lobate, 

 smooth above, dark-grey or copper coloured, beneath with dark, 

 rigid, branched fibres ; buds mostly marginal in minute flat 



