LEPTOGirM.] 



C'OLLEMEI. 



63 



to tlu! auatoniical stiuctiire of tlie thallus and the charact*^r of the apo- 

 thecia, it is divided by Nylander into four subgenera, all of which occur in 

 our Islands. 



Subgen. HOMODIUM Xyl. Flora, 1875, p. 297 (<//•. Cromb. 

 Grevillea, xv. p. 12). — Thallus microphylline, granulosc, or variously 

 lobed or fruticulosc, entirely cellular within : gonimia rarely in part 

 moniliform. Apothecia urceolate or biatoroid; spores variously 

 septate and divided. 



Leptogium tenuissimum Koerb. — a. Thalline laciniae, x30. b. Transverse 

 section of thallus, x200. c Section of apotheeium (when dry), x30. 

 d. Spores, x500. 



Fig. 16. 



Leptogmm museicola Fr. — a. Thalline branch, XoO. a'. Branchlet with a 

 spcriiiogoue, X30. h. Transverse and longitudinal sections of thallus, X 200. 

 c. Spores, XoOO. d. Sterigmata and spermatia, x500. 



