Lichens of Santa Cruz Peninsula 345 



7. USNEA LONGISSIMA Ach. 



Thallus pendulous, finally exxessively elongated, terete or 

 basally slightly compressed, sparingly branched; thickly 

 clothed with simple, nearly straight, horizontal, comparatively 

 short fibrils. Apothecia small or very small, lateral or terminal ; 

 concolorous or pale tan ; color a soft but bright silvery or gray- 

 green ; herbarium specimens fading badly, becoming finally a 

 yellowish green. 



On trees above 1500 feet, in the redwood formation. 



About the head of Purissima Creek, at an altitude of 1900 

 feet, the long, swaying, silver gray fronds of this lichen form 

 a conspicuous feature of the landscape. Here it attains a length 

 of eight or nine feet, but owing to its inaccessible situation only 

 fragments are obtainable, my largest specimens being but about 

 five feet in length. 

 Usnea longissima Ach. Lich. Univ. 626. 1810. 



8. USNEA CALIFORNICA Herre, sp. nov. 



Thallus large, stout, terete, much elongated and pendulous, 

 smooth ; the coarse branches irregularly divided and wide- 

 spread, readily traceable nearly to the extremity of the plant ; 

 secondary branches long and sub-divided ; sparsely clothed with 

 fibrils ; branchlets and fibrils occasionally sorediate ; color gray- 

 green to yellowish green. Fruiting specimens rare ; apothecia 

 borne on second branches, terminal or lateral, small to medium 

 size ; concolorous or tan. 



On trees. 



As yet only seen about the head of Alpine Creek Canon at 

 an altitude of 1000 feet ; locally abundant. 



A robust, conspicuous plant, reaching a length ordinarily of 

 2-3 feet and probably the bulkiest of our Usneas. Quite dif- 

 ferent in habit and general appearance from all our other species. 



" Species adhuc non descripta, similem in Mexico lectan vidi 

 in herbario Horti Vindobonensi." — Zahlbruckner. 



Type, No. 194, Stanford Univ. Herbarium. Cotypes in Royal 

 Botanical Museum, Vienna, Austria ; Stanford Univ. Her- 

 barium; Herbarium of Dr. H. E. Hasse ; and Herbarium of A. 

 C. Herre. Type locality, head of Alpine Creek Canon, San 

 Mateo County, California. Coll. A. C. Herre, July 28, 1903. 



