OF ARTS AND SCIENCES : SEPTEMBER 11, 1866. 227 



lato pallide stramineo, hypothallo nigricante ; apotlieciis minutis sessili- 

 bus lecanorinis, margine obtuso mox fusco-nigricante, disco concolore 

 papillate, demum rugoso-plicatis. Sporge octonje in thecis, parvie, obtu- 

 sissime ellipsoidete, diblastoe, diam, subduplo longiores, fuscae. — Volcanic 

 rocks, Oahu (Mann). — Apothecia at length rather elevated, and cu- 

 riously contorted ; illustrating, both in this respect and in their decol- 

 oration, those of Umbilicaria. 



Pertusaria velata (Turn.) Nyl, Scand., the states resembling 

 Lindig, Lich. N. Gran. u. 2,G58. — Trees, Waialua Mountains, Oahu 

 (Mann). 



Pertusaria Wulfenii, DC. — Volcanic rocks, Oahu (Mann). 



Pertusaria leioplaca (Ach.) Schser. — Trunks, Oahu (Mann). 



Gyalecta lutea (Dicks.) Tuck. — Hawaiian Islands (Remy), 

 Nyl. 1. c. ; Oahu, Lanai (Mann). 



Urceolaria cinereo-c^sia (Sw.) Ach. — On the earth, Kaala 

 Mountains, Oahu (Mann). 



Urceolaria actinostoma, Pers. — Volcanic rocks, Oahu (Mann). 



Thelotrejia calvescens, Fee. — Trunks, Oahu (Mann). 



Thelotrema terebratum, Ach. — Trees, Oahu (Mann). 



Thelotrema cavatum, Ach., Nyl., var. — Trunks, Oahu (Mann). 

 * Thelotrema piluliferum (sub-sp. nov.) : thallo subtartareo con- 

 tiguo 1. aequabili 1. verruculoso glaucescente albidove cum hypothallo 

 confuso; apotheciis confertis superficialibus globularibus subclausis, 

 excipulo exteriori apice poro pertuso propi'ium integrum fuscum 

 fovente, disco concavo pallido. Sporas octonce, cocciformes, muriformes 

 (ser. transv. dein 6, long. 2-3) diam. subduplo longiores, incolores. — 

 Trees, Oahu (Mann). — With quite the aspect, in some of the speci- 

 mens, of a Pertusaria, not remote from conditions of P. velata. The 

 Lichen is evidently closely allied to Thelotrema pachystomum, Nyl. 

 (Wright, Lich. Cub. n. 131; Lindig, herb. N. Gran. n. 55, 88, coll. 

 2dae^ from which it especially differs in its cocciform, muriform-pluri- 

 locular spores ; the spores of the other being regularly quadilocular, 

 and affording no indications of ulterior development. But both alike 

 of these decolorate spore-forms belong, we believe, to the colored type ; 

 and in fact one of them expresses what is exactly the younger condi- 

 tion of the other. The discrepancy in shape and in the measurements 

 between the spores of the Oahu Lichen, and those of the West Indian 

 and South American ones appears to be due entirely to the distention 

 which so commonly accompanies the evolution of the muriform stage. 



