R. H. Howe: MANUAL OF THE GENUS USNEA 11 
OBSERVATIONS : This species is certainly closely allied to U. 
cavernosa. Except for articulate inflated thallus, it is in every 
way similar. None of the specimens I have examined have been 
truly papillate. That it is an accidental monstrosity was the 
opinion of Fries and later writers. If not a ‘ monstrositas’’ its 
morphological differentiation certainly deserves for it full specific 
rank. The scarcity of plants of this species in herbaria points to 
its rarity and limits its study. Only a field investigation of grow- 
ing plants can solve its true identity. 
The variety dinorpha of Miller from Cuba I have been unable 
to see. The following original description must uphold its own 
case: “ Usneaarticulata Hoftm. v. dimorpha Mill. Arg. ; straminea, 
rami tenues et laevissimi, parce articulati, ramillis modice numerosis 
aliis capillaribus elongatis laevibus aut minute nodulosis et simul 
aliis intermixtis confertim divaricato-ramosissimis et crebre tuber- 
culosis quasi nodulosis praediti; apothecia parvula, straminea, 
crebre ciliata, cilia breviuscula, simplicia et rudimentarie divaricato- 
ramulosa et partim nodulosa.— Habitu ad U. dasypogotdis v. 
exasperatum Mull. Arg. accedit, sed rami minus dense ramilligeri, 
tenuiores et distincte articulati, parce impressuli, ramilli demum 
dimorphi. — Cuba, ramulicola in Pinal de Sta. Ana, alt. 2400 
ped.: Eggers Flor. Ind. Occ. exs. n. 5015.’’ Disposition of 
type not indicated. 
UsNEA CAVERNOSA Tuck. 
Type: In the Tuckerman herbarium, Botanic Museum, Har- 
vard University, Cambridge, Mass. 
Type Locauity : ‘Ad arbores in oris Lacus Superioris.”’ 
ORIGINAL DESCRIPTION: ‘‘Thallo pendulo laxo molli glaberrimo 
tereti:compresso plus minus cavernoso ochroleuco, ramis primori- 
bus simpliciusculis subventricosis attenuatis ad apices dichotome 
ramosis, ramulis ultimis tenuissime capillaceis ; apotheciis sessilibus 
radiatis disco albido-pruinoso demum subcarneo margine obscuriori 
evanescente.’’ Agassiz & Cabot, Lake Superior, etc. 71. 1850. 
Ficures: None. 
Synonymy: Usnea cavernosa Tuck. Agassiz & Cabot, /oc. cit. 
Fi EOS 
Diacnosis: Zhal/us pendulous, terete or subterete, /oveolate 
fibrils capillaceous, 
