1895.] Botany. 481 
R. laevigata Fr. Trees. Orizaba. (Smith 52). 
R. denticulata (Eschw.) Nyl. Trees. Orizaba. (Smith and Bruner 
53). Spores more or less curved, 13-16 
4—5 
mic. 
R. denticulata canalicularis Nyl. Trees. Orizaba. (Bruner 54). 
Differs from the species in being smaller, slenderer, and the 
main branches becoming divided inte many attenuate, chan- 
nelled branches. Apothecia much as in the species. Spores 
smaller 
R. aay pA (Pers.) Fr. Trees. Orizaba. Alt. 12,000 ft. 
(Smith 56). 
R. ce fraxinea (L.) Fr. Trees. Orizaba. (Smith 55). 
Apparently not as common as the preceding. 
R. pollinaria Ach.? var.? “ Trees in forest, slope of Mt. Orizaba, 
alt. 9-12,000 ft.” (Smith 89). 
Though this lichen has the aspect of pollinaria it differs in be- 
ing more rigid, larger, and more densely branched, and in 
having narrower spores. It may prove to be undescribed. 
Cetraria. 
C. madreporiformis (Ach.) Müll. A single specimen on earth on 
= Orizaba. (Smith 3). 
Evern 
E. PEPEN (L.) Mann. Trees. N. W. slope of Mt. Orizaba. 
Smith 5). 
Very plentiful at an altitude of 11,000-12,500 ft. 
Usnea. 
U. florida (L.) Hoffm. Trees. Orizaba. (Smith 6). 
Abundant at 12,000 ft. alt i 
U. florida strigosa Ach. Trees. Orizaba. (Bruner 8). 
Plentiful. 
U. florida mollis (Stirt.) Wainio. On oak trees, slope of Mt. Orizaba 
at Jalapasco. Alt. 9-11,000 ft. Notuncommon. (Smith 80). 
U. florida rubiginea Michx. Trees. Orizaba. Rare. (Smith 79). 
U. hirta (L.) Hoffm. Trees. Orizaba. (Smith 7) 
U. ceratina Ach. Trees. Orizaba. (Smith 9). 
U. angulata Ach. Trees. Orizaba. (Smith 13). 
U. longissima Ach. Trees. Orizaba. (Smith 14). 
U. cavernosa Tuckerm. “ Hanging from branches of oak trees, Jala- 
pasco.” Alt. 10-12,000 ft. Abundant. (Smith 15). 
This species is sometimes mistaken for U. plicata, but may be 
readily distinguished by the scarcity of fibrils and by the lacu- 
-nose surface, even when sterile. 
