Leila M. Shultz

Modeling distributions of rare plants in the Great Basin, western North America

Abstract In this 2-phase study, we developed field-validated site and landscape-level predictive models for identifying potential rare and endemic plant habitat in the Great Basin of western North America. Four species were chosen to include a range of environmental variability and plant communities. Herbarium records of known occurrences were used to identify initial sample sites. The geographic coordinates, environmental attributes, and vegetation data collected at each site were used to develop 2 predictive models for each species: a field key and a probability-of-occurrence or predictor map. The field key was developed using only field data collected at the sites on environmental attributes and associated species. Predictive maps were developed with a geographic information system (GIS) containing slope, elevation, aspect, soils, and geologic data. Classification-tree (CT) software was used to generate dichotomous field keys and maps of occurrence probabilities. Predictions from both models were then field-validated during the 2nd phase of the study, and final models were developed through an iterative process, in which data collected during the field validation were incorporated into subsequent predictive models. Cross-validated models were >96% accurate and generally predicted presence with >60% accuracy. These models identified potential habitat by combining elevation, slope, aspect, rock type, and geologic process into habitat models for each species. Nomenclature and distributions: Welsh et al. 2003, Shultz et al. 2005.

Sphaeromeria, a genus closer to Artemisia than to Tanacetum (Asteraceae: Anthemideae)

A new species,Sphaeromeria ruthiae, from Zion National Park, and three new combinations,S. martirensis,S. compacta, andS. potentilloides var.nitrophila, are presented. Morphological and anatomical evidence is used to support the recognition ofSphaeromeria as distinct fromTanacetum.

STUDIES OF A NEW HYBRID TAXON IN THE ARTEMISIA TRIDENTATA (ASTERACEAE: ANTHEMIDEAE) COMPLEX

ABSTRACT . Members of the Artemisia tridentata complex (ASTERACEAE; Anthemideae: Artemisia subgen. Tridentatae) have adapted to changing environmental conditions through geographic migration, introgression, and hybridization. These processes have resulted in morphologic and genetic variation. A presumed hybrid (“Bonneville” big sagebrush) of the complex occurs in the moister ranges of A. t. ssp. wyomingensis and can be found growing with shrub species commonly associated with A. t. ssp. vaseyana. These populations appear to be preferred habitat for sage-grouse and are more heavily grazed by ungulates than the parental populations. We determined ploidy levels and conducted a detailed morphological analysis to determine if “Bonneville” is a hybrid entity. Sixteen populations (12 in Oneida Co., ID, and 4 in Rich Co., UT) were selected for the study, representing the putative hybrid (Taxon B) and the putative parents— A. t. ssp. vaseyana (2n = 18), A. t. ssp. wyomingensis (2n = 36), and A. t. ssp. tridentata (2n = 36). Each population consisted of 25 randomly selected individuals for a total of 400 samples. Our analysis showed 3 populations with morphological and chemical characteristics indicating introgression of A. t. ssp. wyomingensis with populations containing A. t. ssp. vaseyana. Based on these results, we designate the Bonneville sagebrush with formal hybrid status of nothotaxon: Artemisia tridentata ssp. × bonnevillensis H. Garrison, L. Shultz, and E.D. McArthur [pro subsp.], 2n = 36.

Penstemon pinorum (Scrophulariaceae), a new species from Utah

Penstemon pinorum, from the Pine Valley Mountains of southwestern Utah, is described and illustrated. It is compared morphologically and ecologically to other members of sectionCristati.

A new species of Townsendia (Asteraceae) from northern Arizona

Townsendia smithii, from northwestern Arizona, is described, illustrated and contrasted with other Arizona species in a key.

A new species of penstemon (Scrophulariaceae) from southwestern Utah

Penstemon ammophilus, an endemic to Canaan Moutain in Washington Co., Utah, is described and illustrated. On the basis of anther characteristics it is placed in sectionGlabri, seriesVirgati, where it nearly links the group to sectionCristati. It is distinct from all the species of both sections with its peculiar papillose-glandular pubescence.

A new Haplopappus (Asteraceae: Astereae) from Nevada

A new species, Haplopappus graniticus, is described and illustrated. Its relationships seemingly lie with section Tonestus but its narrow heads and imbricated phyllaries are anomalous in that section.

A new species of Hackelia (Boraginaceae) from Utah

Hackelia ibapensis, a new species of Boraginaceae (Subfamily Boraginoideae, Tribe Eritrichieae) from the Deep Creek Range of Utah is described and illustrated.