The Genus Porella in North America West of the Hundredth Meridian

Abstract

Eleven species of Frullania occur in North America west of the hundredth meridian. species are discussed and a key is provided. following are new reports: F. bolanderi in Alaska and Arizona; F. brittoniae in Arizona; F. inflata in Nebraska; F. eboracensis in Arizona, New Mexico, and South Dakota; and F. riparia in Arizona and Colorado. generic name Frullania was first established by Raddi (1818) using Frullania major Raddi (= F. tamarisci (L.) Dum.). genus is characterized by 1) dioicous, rarely paroicous or autoicous sexuality; 2) reddish-brown to blackish color; 3) pinnately branched stems 8-16 cells across in transverse sec- tion; 4) Frullania-type lateral branching; 5) un- equally complicate-bilobed leaves with incubous dorsal lobes and inflated ventral lobes; 6) filiform stylus; 7) bilobed (rarely undivided) underleaves; 8) 2-5 pairs of bracts with innermost pair sometimes adnate to the bracteoles; 9) strongly trigonous peri- anth with crenulate mouth; and 10) pyriform-obo- void calyptra. earliest work that dealt with western North American Frullania was that of Mitten (1865) who listed Frullania nisquallensis, collected in Vancou- ver and Orcas Islands by Dr. Lyall (as F. tamarisci L.), with the comment The species are very slen- der, and at first sight would scarcely be supposed to belong to the same species as the European forms. In 1937-1947, Frye and Clark treated the following eight species for the western half of North America: F. bolanderi Aust., F. brittoniae Evans, F. califor- nica (Aust.) Evans, F. chilcootiensis Steph., F. fran- ciscana M. A. Howe, F. inflata Gott., F. nisqual- lensis Sull., and F. riparia Hampe ex Lehm. Recently Godfrey and Godfrey (1980) described F. hattor- iana from British Columbia, Canada. Except for the work of Frye and Clark, no previous study of the genus has been attempted for western North American species. Two subgenera, Frullania and Trachycolea Spruce, with eleven species are treated here.