THE LICHEN FLORA OF THE SANTA CRUZ PENINSULA 225 



redwood formation, often reaching a length of four feet. Native to 

 Europe, North and South America, the East Indies, and Madagascar. 

 We have the typical form as well as the following variety. 



6. var. PLICATA (Hpffm.) Hue. 



Usnea plicata Hoffmann, Deutsch. Fl. 132. 1791. 



Usnea dasypoga plicata Hue, Nouv. Arch. Mus. Paris. Ser. 4, 1 : 



1899. 



Usnea barbata d. plicata Tuck. Syn. N. Am. Lich. I: 41. 1882. 



Usnea plicata Herre, Proc. Wash. Acad. Sci. 7: 344. 1906. 



Thallus greatly elongated and pendulous, rather coarser than in 

 the type; sub-dichotomously divided, the branches without spread- 

 ing fibrils ; varying from gray-green to straw-color. Apothecia very 

 small and rare. 



Frequent on trees and shrubs above 600 feet; often growing in 

 inextricable confusion with the type. 



7. USNEA ARTICULATA (L.) Hoffm. 



Lichen articulatus Linn. Sp. Plant. 2: 1156. 1753. 



Usnea articulata Hoffmann, Deutsch. Fl. 2: 35. 1791. 



Usnea barbata e. articulata Tuck. Syn. N. Am. Lich. I: 41. 1882. 



Thallus moderately elongate, pendulous, much branched, more 

 or less dichotomous, smooth or minutely sorediose-tuberculate; 

 broken into joints, these more or less inflated basally; my Calif or- 

 nian specimens without fibrils, though material collected in Europe 

 has them present on the entangled secondary branchlets. The artic- 

 ulations are sometimes so distinct and numerous as to suggest beads 

 strung on the medullary axis. 



Sterile with us. 



A distinct and not very abundant plant of the mountain forests. 

 Widely distributed over the earth, absent only from the frigid zones, 

 but not well marked in North America except on the Pacific coast. 



8. USNEA LONGISSIMA Ach. 



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



Usnea longissima Tuck. Syn. N. Am. Lich. I: 43. 1882. 



Usnea longissima Herre, Proc. Wash. Acad. Sci. 7: 345. 1906. 



