John R. Spence

Fire History of Piñon-juniper Woodlands on Navajo Point, Glen Canyon National Recreation Area

Abstract Navajo Point, on the southeast tip of the Kaiparowits Plateau, supports Pinus edullis Engelm. var edulis-Juniperus osteosperma (Torrey) Little (piñon-juniper) woodlands undisturbed by large wildfires in the recent past. We developed a fire history and characterized the current fuel structure and plant biodiversity in the piñon-juniper woodlands on Navajo Point. Using a combination of 18 stand ages, stand structural characteristics classified from satellite imagery, and line intercept sampling, we determined that it would take 400–600 years to burn a cumulative area equal in extent to Navajo Point. Despite a long history of livestock grazing and fire suppression policies, the woodlands on Navajo Point still retain most of their primeval character. Specifically, the landscape patch mosaic on Navajo Point has not been fundamentally altered by 20th century fire exclusion. We conclude that the old-growth woodlands that cover at least half of Navajo Point are a natural and ecologically significant component of this ecosystem, resulting from the combination of the areas soils, climate, and inherently infrequent disturbance regime. Today, the rich understory supports 207 plant species of which only 6% are exotic. Despite the current pristine character of this woodland, the greatest potential threat comes from Bromus tectorum L. (cheatgrass), which occurs intermittently throughout the area. If expansion occurs, this flashy fuel (which has no native counterpart) could significantly shorten the centuries-long fire cycle that has allowed for the development of the biologically rich woodland on Navajo Point.

An annotated checklist of the bryophytes of Nevada, with notes on collecting history in the state

Abstract A checklist of the 310 bryophyte taxa (two hornworts, 46 liverworts and 262 mosses) reported to occur within the political boundaries of the state of Nevada is presented. 238 new county records are also listed. Notes are provided for species with complex synonymies, taxonomic difficulties or interesting histories. This checklist is intended to improve efforts towards a complete bryophyte flora of the state by identifying those species, habitats and geographic regions that have been neglected or poorly sampled.

CONTRIBUTIONS TOWARD A BRYOFLORA OF NEVADA: BRYOPHYTES NEW FOR THE SILVER STATE. PART II.

Abstract Forty-two mosses and three liverworts are reported as new for Nevada. The genera Amblyodon, Campyliadelphus, Isopterygiopsis, Mesoptychia, Myurella, Plagiobryoides, Plagiobryum, Platydictya, Pseudocampylium, and Preissia are new for the state of Nevada. Splachnobryum obtusum and Pseudoleskeella rupestris are now confirmed for Nevada based on recently collected material. Grimmia texicana is excluded from the Nevada checklist based on a herbarium label locality error. The bryoflora of Nevada with 355 taxa is comprised of two hornworts, 49 liverworts, and 304 mosses.

Ptychostomum pacificum (Bryaceae), a new Fen Species from California, Oregon, and Western Nevada, USA

Abstract Ptychostomum pacificum J. R. Spence & Shevock, a new and highly distinctive species restricted to fen habitats within coniferous forests in California, Oregon, and extreme western Nevada is described and illustrated. This species appears to be related to P. turbinatum (Hedw.) J. R. Spence but is easily distinguished by a combination of features including large size, percurrent yellowish-brown costa with numerous incrassate cells at the leaf tip, strongly recurved leaf margins, and elongate cylindrical to narrowly pyriform capsules.

New Combinations in North American Rosulabryum (Bryopsida, Bryaceae)

Abstract For the Flora of North America Project, five species are transferred to Rosulabryum J. R. Spence (Bryaceae). Two weedy European species, Bryum bornholmense Winkelmann & R. Ruthe and B. rubens Mitten, are transferred based on morphology and recent molecular results, as R. bornholmense (Winkelmann & R. Ruthe) J. R. Spence and R. rubens (Mitten) J. R. Spence. The western North American endemics B. erythroloma (Kindberg) Syed and B. gemmascens Kindberg are also transferred to Rosulabryum, as R. erythroloma (Kindberg) J. R. Spence and R. gemmascens (Kindberg) J. R. Spence. Finally, the rare eastern North American Brachymenium andersonii H. A. Crum is transferred to Rosulabryum as R. andersonii (H. A. Crum) J. R. Spence. In all, 13 species of Rosulabryum are found in North America north of Mexico. A key to the species is included.

Four Species of the Bryaceae New to the U.S.A.

Abstract. Recent floristic and herbarium work has revealed four species of the Bryaceae new to North America north of Mexico. Brachymenium exile is reported from southern Florida, while Brachymeniun vinosulum is reported from springs in Arizona, Colorado and New Mexico. Bryum mildeanum is reported from Maine and the mountains of Colorado, while Bryum veronense is reported from Colorado in a semiarid site in the Front Range.

New and Interesting Species of Gemmabryum J.R. Spence & H.P. Ramsay (Bryaceae, Bryopsida) From California and the West

Abstract Three species in the genus Gemmabryum J.R. Spence & H.P. Ramsay are described and illustrated. Two species, G. brassicoides J.R. Spence & K.M. Kellman and G. vinosum J.R. Spence & K.M. Kellman, are new to science. The third species, G. californicum (Sull.) J.R. Spence, previously considered to be part of G. dichotomum (Hedw.) J.R. Spence & H.P. Ramsay, is re-instated as a full species due to its highly unusual bulbil morphology. Gemmabryum vinosum is distributed in California, Oregon, and Montana, while the other two species are endemic to California.

Imbribryum torenii (Bryaceae), A New Species From Western North America

Abstract Imbribryum torenii J.R. Spence & Shevock is described and illustrated. This species appears related to I. alpinum (Hudson ex Withering) N. Pedersen and I. muehlenbeckii (Bruch & Schimper) N. Pedersen. Imbribryum torenii is readily distinguished from these two species by a combination of characters including broadly ovate leaves, short excurrent costa, hexagonal distal laminal cells, cylindric capsule, and large spores.

Comments on the Cryptogam Vegetation in Front of Glaciers in the Teton Range

The cryptogamic vegetation on neoglacial till at eleven sites in the Teton Range, Grand Teton National Park, Wyoming, was investigated. Nine of the sites are moraines fronting glaciers, while two sites are rock glaciers. The distribution and abundance of terricolous cryptogams is strongly correlated with aspect: north and northeast facing sites support better developed vegetation than south and southeast facing sites. Distribution of saxicolous lichens is controlled more by substrate age and type than aspect. The steep moraine slopes are too dry and unstable to allow the establishment of terricolous cryptogams. Cryptogams often play an important role in the early stages of succession in front of retreating glaciers. Studies have shown that cryptogam colonization is generally rapid, often within one to three years following ice recession (Palmer & Miller 1961; Persson 1964; Einarsson 1970; Worsley & Ward 1974). The first pioneers are often species of Rhacomitrium, Pohlia, Bryum, and Polytrichum (Cooper 1923; Stork 1963; Hedberg 1968; Beschel & Weidick 1973; Scott 1974). Most studies have focused on the actual successional sequences, while differences in species distributions and vegetation cover caused by vari- ations in edaphic, topographic, and microclimatic features are overlooked. This paper considers the distribution of cryptogam species and cover in response to differences in aspect and topography on recently formed glacial landforms in the Teton Range, Grand Teton National Park, Wyoming. No long-term climatic data exist for the Teton Range. The climate on the floor of Jackson Hole to the east of the range is continental, with long, cold winters and short, cool summers. Average annual precipitation is about 580 mm yr1, coming mostly as snow in the winter months. Average annual temperature is about 1.3oC (Reed 1952; Shaw 1958). Limited temperature data collected from 3100 m.s.m. in front of the Teton Glacier in the range show that, at ground level, temperatures during the months of July, August, and September are roughly comparable to temperatures on the floor of Jackson Hole during these same three months, despite an elevational difference of about 1000 m. Despite oc- casional snowstorms during the summer months, the lowest temperature recorded at Teton Glacier was about VlC (Spence 1980). METHODS Eleven sites were visited during the summers of 1979 and 1980. These sites, with some charac- teristics, are listed in Table 1. The glacial deposits at the sites were observed as thoroughly as possible on foot, and species abundances visually noted. At several sites data were collected with a 0.5 x 0.5 m quadrat. Total vegetation cover was noted in each quadrat visually. Site data on rock types and topography were collected from site observations, 7.5 min USGS topographic maps, and a geological map produced by Reed (1973). Specimens are deposited in vBc. Data on several crustose lichens are

Grimmia olympica Britt. (Grimmiaceae) is transferred to Brachydontium (Seligeriaceae)

Traditionally, Grimmia olympica Britt. is placed in the genus Grimmia sensu lato. A combination offeatures, however, including habit, size, laminal shape and areolation, morphol- ogy of the leaf apex and costal anatomy, suggest that the species is better placed in the genus Brachydontium (Seligeriaceae). We propose the following transfer and combination: Brachydon- tium olympicum (Britt.) McIntosh & Spence. Comparisons with the other three species of Brachy- dontium are made, and the distribution and ecology of B. olympicum is discussed. A species of moss collected in the Olympic Moun- tains of Washington in 1907 by T. C. Frye was subsequently described by Mrs. E. Britton as Grim- mia olympica Britton (Frye 1910). The decision to place the taxon in the genus Grimmia has been ques- tioned by several workers familiar with the Grim- miaceae. Deguchi (1978), for example, noted that the small size of the gametophore, the lack of a peristome and the appearance of the leaves suggest that G. olympica may be a member of the Seliger- iaceae, in particular the genus Brachydontium. The purpose of this paper is to examine the taxo- nomic position of G. olympica by comparing it with Grimmia (in the strict sense, excluding the genera Schistidium and Coscinodon), as well as with Brachydontium and Seligeria of the Seligeriaceae. Herbarium material, in addition to published de- scriptions and illustrations in Frye (1910), Nyholm (1954), Lawton (1971), Stone (1973), Vitt (1976), Deguchi (1978) and Churchill (1981), were used.