Dudleya Cymosa Subsp. Costafolia (Crassulaceae), A New Subspecies from the Southern Sierra Nevada, Tulare County, California

Dudleya cymosa subsp. costafolia, a new subspecies from the southern Sierra Nevada, Tulare County, California, is described and illustrated. Along with bright yellow flowers, the cespitose plant produces numerous, small rosettes with rib-shaped linear to linear-oblanceolate leaves, which are unique to the subspecies. The authors have searched numerous other rock outcrops, especially limestone, in the general area for additional plants with no success. Dudleya cymosa subsp. costafolia evidently is restricted to a solitary limestone outcrop north of the South Fork of the Middle Fork of the Tule River

Monardella Stebbinsii (Lamiaceae), A New Serpentine Endemic Species from the Northern Sierra Nevada, Plumas County, California

Monardella stebbinsii (Lamiaceae ), a new species from the northern Sierra Nevada of Plumas County, California, is described and illustrated. Characterized by ovate leaves, multiple verticillasters per infiorascence, a matlike habit, reddish papery bracts, and purplish-red leaves with a soft white pubescence, the species is not closely related to any other species of the genus. The new species is apparently restricted to the central portion of a serpentine outcrop located north and east of the confluence of the North Fork of the Feather River and its East Branch

Forty Years of Change in Piute Cypress (Hesperocyparis nevadensis), a Rare California Tree, After Frequent Fire and Drought

Piute cypress (Hesperocyparis nevadensis) is a rare cypress species endemic to the Lake Isabella region in the southern Sierra Nevada in California. Piute cypress groves have not been quantitatively studied in the last 40 years and with recent fires (some in short succession) and observed mortality, we had questions surrounding conditions in groves recovering from fire compared to other groves with no recorded fire histories. Piute cypress rarely survive fire and are obligate seeders with serotinous cones and, as such, require sufficient time after fire to grow to reproductive maturity to be able to withstand future fire. We visited five of the 12 known groves of Piute cypress to evaluate current stand conditions and make comparisons with an assessment conducted 40 years ago. We evaluated two recently burned groves nine years post-fire. One grove with a shorter interval between fires (~20 years), has only limited regeneration and is at risk of local extinction. Based on our findings, we extrapolated to unstudied groves to conclude that five recently burned groves are vulnerable to immaturity risk if these stands were to reburn soon. We recommend aggressive fire suppression tactics to protect these groves if threatened by fire. Another recently burned grove with a longer period between fires (~90 years) appears to be recovering and capable of becoming a self-sustaining population that can survive another fire based on regeneration data. While the 90-year-old trees did not have nearly the level of canopy seed bank that older trees (~200 years old) did in another part of the grove, seedling and sapling regeneration after fire occurred at higher densities than tree densities in mature stands and were already developing cones. Though theoretically long-unburned groves also may be at risk, we found no evidence of age-related decline in this long-lived species and some non-fire induced regeneration. We did discover evidence of cedar bark beetle attack (Phloeosinus), particularly in smaller trees at two unburned groves. which was correlated to high tree mortality (31.6%) at one site. While we found no evidence of encroaching non-cypress tree species threatening long-unburned groves among mature cohorts, we did document relatively high densities of regenerating non-cypress tree species in groves. We strongly recommend further monitoring in groves to assess fire, insect, and disease vulnerability in cypress populations

Infraspecific variation in Hesperocyparis abramsiana: ISSRs and terpenoid data

Volume: 91Start Page: 287End Page: 29

DUDLEYA CALCICOLA (CRASSULACEAE), A NEW SPECIES FROM THE SOUTHERN SIERRA NEVADA

Volume: 30Start Page: 210End Page: 21

DISTRIBUTION, ECOLOGY, AND TAXONOMY OF ERYTHRONIUM (LILIACEAE) IN THE SIERRA NEVADA OF CALIFORNIA

Volume: 37Start Page: 261End Page: 27

Geographic variation in the leaf essential oils of Hesperocyparis arizonica and H. glabra

Volume: 92Start Page: 366End Page: 38

NOTEWORTHY COLLECTIONS

Volume: 28Start Page: 184End Page: 18

Polyploidy in Cupressaceae: Discovery of a new naturally occurring tetraploid, Xanthocyparis vietnamensis

While polyploidy (whole-genome multiplication) is generally considered rare in extant gymnosperms (with the exception of Ephedra, Ephedraceae), the occurrence of sporadic polyploid individuals belonging to various genera in the conifer family Cupressaceae has been reported in the literature. In addition, recent studies have revealed that polyploidy is not uncommon in the genus Juniperus (Cupressaceae), with tetraploid and hexaploid individuals reported in individuals collected from wild populations. Given these findings, we undertook a comprehensive screening of ploidy levels in 32 species belonging to the four genera that are phylogenetically closest to Juniperus (i.e., Callitropsis, Hesperocyparis, Xanthocyparis, and Cupressus), referred to as the CaHXCu complex. In addition, we also determined the ploidy level of two accessions in the poorly studied tetraploid, Fitzroya cupressoides. Using flow cytometry together with published chromosome counts to assign ploidy levels, we show that all species of the CaHXCu complex are diploid except Xanthocyparis vietnamensis, which is tetraploid, with a genome size of 44.60¿pg/2¿C. This study opens up new opportunities for studying the impact and consequences of polyploidy on the evolution and adaptation of species in Cupressaceae.This research was supported in part by funds to RPA from project 0324512, Baylor University1 Introduction 2 Material and Methods 2.1 Plant material 2.2 Genome size assessment and ploidy level determination 3 Results 3.1 Ploidy level screening of species belonging to the CaHXCu complex 3.2 Genome size assessment of Xanthocyparis vietnamensis 4 Discussion 4.1 Novel tetraploid uncovered in Cupressaceae—the endemic Xanthocyparis vietnamensis 4.2 Polyploidy in Cupressaceae 5 Conclusion Acknowledgement