22 Jllhioh Stdfp Laho)-aiori/ of Nattiral Hhtorij. 



tenuis). Thallus at first racliately divided from the centre, 

 which often soon decays; the divisions bifid or di-trichotomous, 

 plane, depressed or canaliculate above, and usually convex and 

 naked or squamulose beneath; margins either naked or spinu- 

 lose-ciliate. Epidermis usually distinct, eporose; air cavities 

 evident in some species, wanting in others. Rootlets papillose 

 within (except in 7?. Frosfri ). Named for F/cc/'. an Italian 

 botanist. 



§ 1. LicHENODES Bisch. T/ialJus solid, witliout air cari- 

 fies; fruit mostly protuherant above; spores about 0.084 mm. in 

 diameter, angular, issuing through oj)enings which at length ap- 

 pear in the upper surface of the thalJus. Terrestrial species 

 growing on damp, usually trodden or cultivated ground, and 

 closely adhering to it. 



* Thallus n(drd on tlie margins or underneath (irithout cilia or 

 scales). 



1. R. Frostii Aust. Thallus orbicular, 1.3 — 2.5 cm. in 

 diameter, subsolid, thinnish, subpalraately or radiately divided, 

 cinereous-green, fibrously reticulate, minutely pitted and either 

 plane or channeled above, concolorous or tinged with prnrple 

 toward the apex beneath, very narrowly membranous, somewhat 

 papillose-squamulose, and often tinged with pmrple on the )uar- 

 gin; divisions linear or subspatulate-linear, subdichotomous; 

 lobes subtruncate and indistinctly emarginate; rootlets smooth 

 or obsoletely papillose within; capsules irregularly disposed, 

 very prominent underneath; spores nearly round, barely 0.051 

 mm. in diameter, fuscous, somewhat margined, minutely and 

 obscurely reticulated and granulose-papillose, tJie sides strongly 

 depressed when dry. 



Ifoft.— Nev. (Watson), Col. {Wolfe), 0. (Beardslee), 111. (HaU). 

 5i?).— Toriey Bull. VI, p. 17. 



2. R. Watsoni Aust. Dioecious; thallus of male plant 

 small, fuscous-pnrple both sides, orbicular, deeply and many 

 times divided, thick, fleshy, broadly pitted, papillose, fibrous- 

 reticulate and with ratlier large, terete subclavate, gland-like 

 papillw (ostioles?) abore, densely radiculose and nodulose be- 



