California Floristic Province Research Articles

Fire History, Stand Origins, and the Persistence of McNab Cypress, Northern California, USA

Despite their substantial contribution to the uniqueness and diversity of the California Floristic Province’s flora and vegetation, surprisingly little is known about the region’s native cypress species (genus Hesperocyparis Bartel & R.A. Price). Current ideas about the fire regimes that maintained these species in the past are based largely or solely on assumptions about the expression and function of life-history characteristics. Empirical studies of fire history are generally lacking. I used a combination of dendrochronological methods, field observations, and contemporary fire records to investigate the history of fire and its role in stand development in McNab cypress (Hesperocyparis macnabiana [A. Murray bis] Bartel), an uncommon serotinous cypress endemic to northern California. Although even-aged stands were present within all 20 populations surveyed, 4 populations also contained stands exhibiting uneven age structure. Fire records and field observations confirmed that even-aged stands originated following stand-replacing fires, but no link between fire and recruitment was found for uneven-aged stands. Rather, trees within uneven-aged stands were generally older, larger, and exhibited higher rates of senescence than those found in even-aged stands, suggesting that inter-fire tree mortality and inter-fire establishment may be linked. When aggregated, the dates of stand-replacing fires (derived from stand recruitment dates and fire records) revealed that relatively few stand-replacing fires occurred in McNab cypress populations during the 50 yr period between 1940 and 1989 (1 fire per decade) compared to either the previous 100 yr period (at least 3 fires per decade) or the subsequent 20 yr period (3.5 fires per decade). This suggests that short fire return intervals do not appear to be a significant threat to McNab cypress persistence at the present time, and there is little ecological justification for fire exclusion.

Homalothecium californicum (Brachytheciaceae), a new endemic species to the California Floristic Province, Pacific Coast of North America

A new species of Homalothecium from California is described and illustrated. This species was first recognized as distinctive during analysis of a DNA investigation into members of Homalothecium and related genera. Homalothecium californicum sp. nov. is distinct in its frondose branching, patent to loosely erect leaves, size intermediate between the somewhat similar H. megaptilum and H. nevadense, and cylindrical, straight, and orthotropous capsules with basally reddened exostome teeth. Subsequent herbarium and field exploration determined this new species to be a rather common and widespread species in central and northern California within a mixed conifer-hardwood transition zone. Several herbarium collections of this new species were found previously determined as Homalothecium megaptilum, H. nevadense, H. fulgescens or H. aeneum.

Analysis of the non-native flora of Ensenada, a fast growing city in northwestern Baja California

Urbanized areas show a high proportion of non-native plants and can work as dispersal points to the surrounding areas. Ensenada is a fast growing city located in the northwestern peninsula of Baja California (Mexico). It is the southern extreme of a bi-national, coastal urban corridor that extends from Los Angeles, California south to Ensenada. This corridor is part of the biodiversity hotspot of the California Floristic Province. The aim of this study was to analyze the composition and distribution of the spontaneous flora in the city of Ensenada. We systematically sampled two differentiated urban environments, vacant lots and arroyos, in 2006 and 2007. We found a total of 158 plant species, 61% of them were non-native species. Arroyo areas showed higher non-native species richness than vacant lots (21.9 vs. 13.6 species/transect) and could be potential dispersal vectors for non-native species to natural areas outside of the city, or in the reverse direction also.

Phylogenetic Relationships and Taxonomic Status Of the Paleoendemic Fagaceae Of Western North America: Recognition Of A New Genus, Notholithocarpus

Abstract We investigated the phylogenetic relationships and taxonomic status of the castaneoid component (Lithocarpus and Chrysolepis) of the family Fagaceae that is endemic to the California Floristic Province (CA-FP). Over 7800 basepairs of nuclear and chloroplast DNA were analyzed in 17 taxa representing the breadth of phylogenetic diversity in the family. The genus Lithocarpus, as currently defined, is clearly polyphyletic due to the inclusion of L. densiflorus. Here, we designate this taxon as a new genus, Notholithocarpus, which can be recognized morphologically by its relatively small, subprolate pollen. Notholithocarpus is more closely related to Quercus, Castanea, and Castanopsis; Chrysolepis was resolved as the sister group to Lithocarpus sensu stricto. These results indicate that Notholithocarpus does not possess true ‘flower cupules,’ which define Lithocarpus sensu stricto, but like the oaks, the single flower per cupule is derived through the abortion of lateral flowers within each cupule. Fu...

Guadalupe Island: Lost paradise recovered? Overgrazing impact on extinction in a remote oceanic island as estimated through accumulation functions

Guadalupe Island, an oceanic island in the northwest of Mexico, is an outlier of the California Floristic Province that has been disturbed by introduced goats for more than a century, with dramatic effects of goats on plant communities and local species extinctions. In 2004 the island went through a successful eradication program. Since then, six previously unrecorded species have been discovered and four supposed extinct species have been found again. Quantifying the true species richness of the island at the time of eradication, to set a benchmark for the future monitoring of this large-scale natural experiment, is both a challenge and a necessity. For this purpose, we estimated (a) current and (b) accumulated historical plant species richness of the island through accumulation functions. Estimation of current species richness was based on the geographical accumulation process of species richness (80 species) obtained from sampling 110 (50 m × 2 m) transects distributed along the island in year 2004. Historical species richness was estimated through the temporal accumulation of species richness (119 species) from botanical records (1,960 specimens reviewed) between 1875 and 2000. The predicted value of historical richness (213 species) is similar to known historical records (218 species), but estimation of current richness (203 species) is significantly higher than accepted extant plant richness (187 species). Our results suggest that currently there may be more plant species living in the island than estimated through recent botanical exploration. Future monitoring of the island as it recovers will clarify this hypothesis.

Coyotes Demonstrate How Habitat Specialization by Individuals of a Generalist Species Can Diversify Populations in a Heterogeneous Ecoregion

The tendency for individuals to disperse into habitat similar to their natal habitat has been observed in a wide range of species, although its population genetic consequences have received little study. Such behavior could lead to discrete habitat-specific population subdivisions even in the absence of physical dispersal barriers or habitat gaps. Previous studies of coyotes have supported this hypothesis in a small region of California, but its evolutionary significance ultimately depends on the extent and magnitude of habitat-specific subdivision. Here, we investigated these questions using autosomal, Y chromosome, and mitochondrial markers and >2,000 coyotes from a broad region, including 2 adjacent ecoregions with contrasting levels of habitat heterogeneity--the California Floristic Province (CFP) (heterogeneous landscape) and the Desert-Prairie ecoregion (DPE) (homogeneous landscape). Consistent with predictions, we found a close correspondence between population genetic structure and habitat subdivisions throughout the CFP and virtual panmixia over the larger DPE. Conversely, although genetic diversity was similar in these 2 ecoregions overall, it was lower within sites of the CFP, as would be the expected consequence of greater genetic drift within subregions. The magnitude of habitat-specific genetic subdivisions (i.e., genetic distance) in the CFP varied considerably, indicating complexity (e.g., asymmetric gene flow or extinction/recolonization), but, in general, was higher than that due to geographic distance or recent human-related barriers. Because habitat-specific structure can enhance a species' adaptive potential and resilience to changing environments, these findings suggest the CFP may constitute an evolutionarily important portion of the range for coyotes and sympatric species exhibiting habitat-specific population structure.

Conservation genetics of three flightless beetle species in southern California

Regional scale conservation decisions can be aided by information on the distribution of intraspecific diversity, especially the extent to which patterns are common to multiple species. We compare patterns of intraspecific mitochondrial cytochrome oxidase I (COI) variation among three flightless beetles (Coleoptera: Tenebrionidae: Nyctoporis carinata LeConte; Staphylinidae: Sepedophilus castaneus (Horn); Carabidae: Calathus ruficollis Dejean) in the southern part of the California Floristic Province biodiversity hotspot. All species exhibit moderate to high levels of total variation, ranging from 2% to 10% (maximum uncorrected distance). Most populations of all species exhibit unique haplotypes, but few populations’ haplotypes constitute exclusive clades. Many adjacent pairs of populations show indications of some, though limited, genetic connectedness, due either to gene flow or ancestral polymorphism. However, in most cases this diminishes sharply over greater distances. By both statistical and phylogenetic measures, Sierra Nevadan populations are highly distinct from those in the coast and transverse ranges. Among the latter, the eastern transverse ranges are generally most unique and isolated, with diversity in the western parts of these ranges showing fewer barriers. Otherwise, few measures agree on areas of highest conservation value, and overall patterns tend to be species-specific.

A phylogeographical analysis of the range disjunction for foxtail pine (Pinus balfouriana, Pinaceae): the role of Pleistocene glaciation

Biogeographical patterns within the California Floristic Province have been greatly affected by geological and climatic events. Here, we investigate the phylogeography of foxtail pine (Pinus balfouriana) in an effort to date its range disjunction using molecular data and to further our understanding of phylogeographical patterns for plants within the California Floristic Province. The distribution of foxtail pine is characterized by a 500-km disjunction separating populations located in the Klamath Mountains from those in the southern Sierra Nevada. Previous authors suggested that this disjunction occurred approximately 4000-8000 years ago during the Holocene Xerotherm when western North America became warmer and drier. Those dates, however, are inconsistent with the morphological differences that separate regional populations into formally recognized subspecies. Using the coalescent-based isolation with migration model and DNA sequence data from the chloroplast, mitochondrial, and nuclear genomes, we evaluate several hypotheses addressing the timing of this range disjunction and its effects on subsequent patterns of gene flow. Results from all three genomes are largely consistent with Middle to Early Pleistocene divergence dates. Those dates correspond to the Sherwin glaciation, which was the largest Pleistocene glacial episode in the Sierra Nevada. Gene flow, moreover, was only documented using data from the chloroplast genome, suggesting that low levels of long-distance pollen dispersal (N(e)m < 0.5) have occurred since this divergence event. These results are extended to a discussion of the biogeographical development of subalpine forests in California.

Flora and Vegetation of an Isolated Mountain Range in the Desert of Baja California

Abstract The presence of species disjunct from more northern distributions and quantitative aspects of species associations were studied on the Sierra La Asamblea, an isolated range reaching 1,661 m elevation at about 29.3°N on the Baja California Peninsula. The flora above 800 m is composed of ≥299 species of tracheophytes, notably including Pinus monophylla and Adenostoma fasciculatum. Eighty-seven species are considered disjunct from more northern distributions, of which only 19 have affinity limited to the California Floristic Province. Data from 10 transects and adjacent flora show few species that are either broadly distributed or locally common, and both composition and structure differ from studies at lower elevations. Disjuncts were most common in association with P. monophylla. Range extensions (38) are reported, including three new records for the peninsula, and a floristic list is provided.

A molecular phylogeny of the wild onions (Allium; Alliaceae) with a focus on the western North American center of diversity

Nuclear ribosomal DNA (ITS and ETS) sequences from 39 native Californian (USA) Allium species and congeners were combined with 154 ITS sequences available on GenBank to develop a global Allium phylogeny with the simultaneous goals of investigating the evolutionary history (monophyly) of Allium in the Californian center of diversity and exploring patterns of adaptation to serpentine soils. Phylogenies constructed with ITS alone or ITS in combination with ETS provided sufficient resolution for investigating evolutionary relationships among species. The ITS region alone was sufficient to resolve the deeper relationships in North American species. Addition of a second marker (ETS) further supports the phylogenetic placements of the North American species and adds resolution within subgenus Amerallium, a clade containing many Californian endemics. Within the global phylogeny, the native North American species were found to be monophyletic, with the exception of Allium tricoccum and Allium schoenoprasum. All native Californian species included in the analysis fell into a monophyletic subgenus Amerallium section Lophioprason, although endemic Californian species were not monophyletic due to the inclusion of species with ranges extending beyond the California Floristic Province. The molecular phylogeny strongly supports previous morphology-based taxonomic groupings. Based on our results, serpentine adaptation appears to have occurred multiple times within section Lophioprason, while the ancestor of the Californian center of diversity may not have been serpentine-adapted.

Regional patterns of recruitment success and failure in two endemic California oaks

ABSTRACTOak woodlands and savannas are key defining landscapes in the California Floristic Province, making up almost a quarter of the region's forests and woodlands. Two endemic Californian oak species, valley oak (Quercus lobata Neé) and blue oak (Quercus douglasii Hook. &amp; Arn.), are widely considered at risk of decline from persistent recruitment failures in the last century. However, decades of research have produced no definitive conclusion about the existence, extent, or causes of this ‘regeneration problem’. Underlying causes of perceived recruitment failure are unclear and could include drivers at distribution‐wide to local scales including climate and atmospheric changes, habitat fragmentation, altered herbivore populations, changing fire regimes, exotic plant and animal invasions, livestock grazing, and soil conditions altered by past land uses. We performed meta‐analyses of existing stand‐scale data from the published and grey literatures on seedling and sapling recruitment in blue and valley oaks throughout each of their distributions. We sought to evaluate whether distribution‐wide regeneration ‘problems’ exist for either species and to assess what factors correlate with distribution‐wide recruitment patterns. Nearly 80% of sites surveyed for blue oaks but fewer than 50% of sites surveyed for valley oaks contained some evidence of seedling or sapling recruitment. A majority of sites surveyed for both species appear to have insufficient recruitment to replace adult populations, though further demographic work would be required to quantify minimum replacement recruitment rates. Reserve sites were seven times more likely than non‐reserve sites to contain valley oak populations with evidence of recruitment. Blue oak recruitment patterns were weakly related to climate and geographical factors and strongly variable at subregional scales. We suggest several lines of additional research that could fill gaps in the existing literature and clarify the patterns emerging from this analysis.

Species richness and complementarity of beetle faunas in a mediterranean-type biodiversity hotspot

Regions of mediterranean-type climate represent most extra-tropical biodi- versity hotspots, being both highly diverse and highly endangered. Though renowned for their plant richness, these regions' insects constitute the bulk of their alpha diversities. Data on insect distribution and rarity are generally lacking for such regions, and are often considered unattainable. Intensive field inventories combined with statistical extrapolation methods can provide a sufficient understanding of alpha, beta, and gamma diversity components for application to conservation planning. These are essential to assessing the adequacy of a regional reserve network for the conservation of insect diversity. Here the beetle faunas of three protected areas spanning three major ecoregions in the California Floristic Province were inventoried and analyzed for species richness, complementarity, and uniqueness. These surveys produced collectively nearly 1,200 species from all three sites, estimated to be about 80% of their total faunas. Diversity was highly partitioned among sites, no one site containing more than 60% of the species. Dissimilarity was moderate to high for all comparisons, and all sites contained >40% unique species. Comparison of these results with those based on species of co-occurring plants reveal incongruent species richness but congruent similarities among sites. These results provide quantitative support to the perception that mediterranean insect faunas show high spatial variability. Along with online specimen level data on distribution, rarity, and seasonality, these results will help speed the incorporation of insect data into serious conservation planning.

RESTORATION IN A CHANGING WORLD: CASE STUDIES FROM CALIFORNIA INTRODUCTION TO SPECIAL ISSUE

As the human footprint occupies an ever increasing proportion of the earth’s surface and resources (e.g., Vitousek 1994; Vitousek et al. 1997; Tilman et al. 2001; Wackernagel et al. 2002), conservation biologists must develop strategies that both protect remnant natural areas and rebuild the ecological integrity of highly altered landscapes (Young et al. 2005). In almost no other region on earth is this need more imperative than in California. California is home to over 36 million residents and has roughly the 7th largest economy in the world, making it a highly human-influenced environment. Yet, the state possesses an exceptional diversity of ecosystems and taxa, many of them threatened with extirpation. The California Floristic Province has been classified as a World Biodiversity Hotspot because of its exceptional level of species endemism and the conservation challenges it faces (Meyers et al. 2000; Konstant et al. 2005). While the mission of the California Botanical Society is to advance the science of western American botany, today it is evident that a key element to that science is learning how to restore native plant communities so that native biodiversity can be sustained over time. There is still much to be learned and the science of restoration ecology is still in its infancy. Furthermore, the practice of ecological restoration must be accomplished in the face of dynamic global changes. In 2005, our board was invited to sponsor a symposium at the 2006 annual meeting of the Society for Conservation Biology (SCB) to be held in San Jose, CA in June 2006. The theme of the conference was ‘‘Conservation without Borders’’. This opportunity inspired us to organize the symposium ‘‘Restoration in a changing world: Case studies from California’’ which took place on Wednesday, June 28, 2006. This special issue is the culmination of that effort. The symposium delivered eight 15 min papers by Michael Vasey, Stuart Weiss, Jeffrey Corbin, K. Blake Suttle, John Callaway, Nathan Stephenson, Jodi McGraw, and Alison Purcell. There was a remarkable congruence between most of these talks and, in fact, several other talks and symposia at the SCB meeting. The common theme was that the threats posed by such elements of global change as climate change (including associated sea level rise), invasion of non-native species, alteration of disturbance regimes, and the input of nitrogen via air pollution are exerting unprecedented pressure on biodiversity, trophic interactions, and the physical structure of ecosystems in California and throughout the world. As many authors have recognized, multiple components of global change are also capable of interacting with each other to affect ecological interactions and the prospects for successful restoration (e.g., Dukes and Mooney 1999; Weiss 1999; Vila et al. 2007). Although Rein et al. (this volume) did not participate in the symposium, we welcome their contribution to this special issue as yet another good example of the challenges that invasive species pose to restoration practitioners. Taken collectively, the results presented in the symposium and in this special issue suggest that the challenges that face sensitive ecosystems will be substantial and will, in some cases, require wholly new strategies if we are to successfully preserve biodiversity and ecosystem function in this age of global change. California is hardly unique in North America, let alone worldwide, in confronting the challenges of climate change, invasive species, and changing land-use. Indeed, nearly every part of the globe must deal with one or more of them. This special issue considers the future of conservation and restoration efforts in California in the face of the myriad threats posed by the local and regional manifestations of several of the most important drivers of global change. We hope that insights gained from these papers can be helpful to scientists and habitat managers in other regions who must also confront the challenge of restoring ecosystems in the face of these challenges.

Limited phylogeographic structure in the flightless ground beetle, Calathus ruficollis, in southern California

ABSTRACTThe California Floristic Province is home to more than 8000 species of beetles, yet their geographical patterns of supra‐ and infraspecific diversity remain largely unexplored. In this paper, we investigate the phylogeography and population demographics of a flightless ground beetle, Calathus ruficollis (Coleoptera: Carabidae), in southern California. We sampled 136 specimens from 25 localities divided into 10 populations using a fragment of the mitochondrial cytochrome oxidase I gene. We tested several hypotheses, including the association of geography with particular clades and populations, the degree of differentiation among regions, and the expansion of populations. Parsimony and Bayesian phylogenetic analyses along with nested clade analysis and amova indicate a deep split between the southern Sierra Nevada population and populations south and west. This split corresponds closely to the split between subspecies C. ruficollis ignicollis (southern Sierra Nevada) and C. ruficollis ruficollis. Populations otherwise exhibit limited geographical structure, though Fst values indicate some local differentiation. Mismatch distributions and Fu's Fs indicate range expansion of several populations, suggesting that some structure may have been obscured by recent exchange. The population of C. ruficollis on Santa Cruz Island, which might have been expected to be isolated, shares several haplotypes with mainland populations, appearing to represent multiple colonizations.

Statistical Assessment of Congruence among Phylogeographic Histories of Three Avian Species in the California Floristic Province

Statistical Assessment of Congruence among Phylogeographic Histories of Three Avian Species in the California Floristic Province

Integrating DNA data and traditional taxonomy to streamline biodiversity assessment: an example from edaphic beetles in the Klamath ecoregion, California, USA

ABSTRACTConservation and land management decisions may be misguided by inaccurate or misinterpreted knowledge of biodiversity. Non‐systematists often lack taxonomic expertise necessary for an accurate assessment of biodiversity. Additionally, there are far too few taxonomists to contribute significantly to the task of identifying species for specimens collected in biodiversity studies. While species level identification is desirable for making informed management decisions concerning biodiversity, little progress has been made to reduce this taxonomic deficiency. Involvement of non‐systematists in the identification process could hasten species identification. Incorporation of DNA sequence data has been recognized as one way to enhance biodiversity assessment and species identification. DNA data are now technologically and economically feasible for most scientists to apply in biodiversity studies. However, its use is not widespread and means of its application has not been extensively addressed. This paper illustrates how such data can be used to hasten biodiversity assessment of species using a little‐known group of edaphic beetles. Partial mitochondrial cytochrome oxidase I was sequenced for 171 individuals of feather‐wing beetles (Coleoptera: Ptiliidae) from the Klamath ecoregion, which is part of a biodiversity hotspot, the California Floristic Province. A phylogram of these data was reconstructed via parsimony and the strict consensus of 28,000 equally parsimonious trees was well resolved except for peripheral nodes. Forty‐two voucher specimens were selected for further identification from clades that were associated with many synonymous and non‐synonymous nucleotide changes. A ptiliid taxonomic expert identified nine species that corresponded to monophyletic groups. These results allowed for a more accurate assessment of ptiliid species diversity in the Klamath ecoregion. In addition, we found that the number of amino acid changes or percentage nucleotide difference did not associate with species limits. This study demonstrates that the complementary use of taxonomic expertise and molecular data can improve both the speed and the accuracy of species‐level biodiversity assessment. We believe this represents a means for non‐systematists to collaborate directly with taxonomists in species identification and represents an improvement over methods that rely solely on parataxonomy or sequence data.

Cryptic species within the cosmopolitan desiccation-tolerant moss Grimmia laevigata

The common cushion moss Grimmia laevigata (Bridel) Bridel grows on bare rock in a broad range of environments on every continent except Antarctica. As such, it must harbor adaptations to a remarkably broad set of environmental stresses, the extremes of which can include very high temperatures, prolonged nearly complete desiccation, and high ultraviolet B (UVB) exposure. Yet, like many mosses, G. laevigata shows very little morphological variability across its cosmopolitan range. This presents an evolutionary puzzle, the solution to which lies in understanding the phylogeographic structure of this morphologically simple organism. Here we report the results of an analysis of amplified fragment length polymorphisms (AFLPs) in G. laevigata, focusing on individuals from the California Floristic Province. We found evidence that populations within California constitute two distinct geographically overlapping cryptic species. Each clade harbors multiple private alleles, indicating they have been genetically isolated for some time. We suggest that the existence of cryptic species within G. laevigata, in combination with its life history, growth habits, and extreme desiccation tolerance, makes this moss an ideal research tool and a candidate for a biological indicator of climate change and pollution.

Population-level history of the wrentit ( Chamaea fasciata): Implications for comparative phylogeography in the California Floristic Province

The phylogeography of a variety of species has been studied within the California Floristic Province; however, few studies have examined genetic variation in bird species across the entire region. This study uses mitochondrial DNA data to investigate the phylogeography of the wrentit ( Chamaea fasciata), a sedentary bird native to scrub and chaparral habitats of this region. Analysis of molecular variance shows geographic structure, and maximum likelihood, Bayesian, and parsimony analyses consistently identify six main clades that are each restricted geographically. Nested clade phylogeographic analyses infer an overall range expansion for the entire cladogram, and a range expansion is also inferred from the mismatch distribution. Thus, our results suggest that the wrentit was isolated into southern refugia during the Pleistocene and has undergone a recent range expansion. Southern refugia and a range expansion were also identified in a previous study of the California thrasher ( Toxostoma redivivum). The wrentit did not show marked divergence between northern and southern California defined by the Transverse Ranges, a pattern seen in a variety of other taxa within this region, including some birds.

A synoptic review of the ants of California (Hymenoptera: Formicidae)

The taxonomy and composition of the California ant fauna is reviewed, leading to the recognition of 281 species (in 44 genera), of which 255 are considered indigenous and 39 are endemic. Species-level endemism (13.9%) is higher than in adjacent regions, as is the percentage of non-native species (9.3%). About one quarter of the indigenous ant species are endemic to the California floristic province (sensu Hickman 1993). Approximately 36 species appear to be undescribed. Most of these undescribed species are assigned code names, which match those used on the “Ants of California” web site (http://www.antweb.org/california.jsp). One new species is described, Camponotus maritimus Ward, sp. nov., which corresponds to the taxon previously called Camponotus maculatus subsp. vicinus var. maritimus Wheeler (unavailable quadrinomen). Three species names are revalidated: Leptothorax calderoni Creighton stat. reval., stat. nov., Myrmica glacialis Emerystat. reval., stat. nov., and Temnothorax rudis (Wheeler) stat. reval., comb. nov. The following new synonymy is proposed (senior synonym listed first): Forelius pruinosus (Roger) = F. analis (André); Monomorium ergatogyna Wheeler = M. wheelerorum DuBois; Temnothorax andrei (Emery) = T. nitens heathii (Wheeler) = T. nitens occidentalis (Wheeler) = T. ocellatus (MacKay); Temnothorax nevadensis (Wheeler) = T. lindae (MacKay) = T. maryanae (MacKay); Temnothorax nitens (Emery) = T. mariposa (Wheeler) = T. melinus (MacKay). The genus Acanthomyops Mayr is demoted to subgenus (stat. rev.) within Lasius Fabricius, in accord with recent molecular phylogenetic results. A key to the ant genera of California (based on the worker caste), a synopsis of each genus, a comprehensive bibliography, and a species list are also provided.Keywords. ant taxonomy, distribution, biogeography, endemism, Camponotus, Lasius, Forelius, Monomorium, Myrmica, Leptothorax, TemnothoraxLike other components of the California biota, the ant fauna of this state shows considerable biological diversity and regional endemism. Yet there has been no comprehensive systematic treatment of the ants of California, much less a reliable checklist or a set of identification keys. Part of this stems from the complexity of the fauna and an attendant rash of taxonomic problems whose resolution requires additional study at a larger geographical scale. In light of these constraints, the present paper aims to provide no more than a cursory survey of the ant genera, a provisional list of species, and a guide to the literature. A few necessary taxonomic changes are introduced, mostly involving new synonymy at the species level. A prime motivation for this paper stems from the need to establish a reference checklist for a new web site illustrating the ants of California (http:// www.antweb.org/california.jsp). This web site, developed in collaboration with Brian Fisher (California Academy of Sciences), is designed to facilitate identification by providing high-quality digital images of the known California ant species. The first descriptions of California ants appeared in the nineteenth and early twentieth century, in widely scattered taxonomic papers by Buckley, Emery, Forel, Mayr, W. M. Wheeler and others. Mallis (1941) and Cook (1953) published a species list and a booklength treatment, respectively, of the ants of California but both of these are out-of-date and error-ridden. Revisionary studies on specific groups of ants, carried out within the last 60 years and usually at a continent-wide scale, have had a more salutary effect on our knowledge of the California ant fauna. This includes taxonomic contributions by Bolton (1979), Brown (1950d, 1953g), Buren (1968b), Cole (1968), Creighton (1950a), Francoeur (1973), Gregg (1959, 1969b), Mackay (2000), Snelling (1970, 1973c, 1976, 1982a, 1982b, 1988, 1995a), Trager (1984b, 1991), Ward (1985b, 1999), Watkins (1976, 1985), Wilson (1955a, 2003) and Wing (1968a). Among the more useful publications for those seeking information about the ants of California are the regional treatments of the ants of Deep Canyon, Riverside County (Wheeler &amp; Wheeler 1973e), the California deserts

Geographic cohesion, chromosomal evolution, parallel adaptive radiations, and consequent floral adaptations inCalochortus(Calochortaceae): evidence from a cpDNA phylogeny

Summary •W e developed a molecular phylogeny for Calochortus (Liliaceae) to reconstruct historical patterns of evolution. • Three cpDNA segments were sequenced and analyzed using parsimony. •W e identified seven major, geographically cohesive clades centered mainly in the California Floristic Province. Section Calochortus is monophyletic; section Mariposa , paraphyletic; and section Cyclobothra , polyphyletic. Calochortus arose in the Coast Ranges, which were uplifited 3‐5 million yr ago. Three of the four major floral syndromes evolved at least twice, associated with particular environments. Serpentine tolerance evolved at least seven times. •W e argue that limited dispersal led to the narrow endemism of individual species, the geographic cohesion of clades, and parallel radiations in habitat preference, floral morphology, and serpentine tolerance. Chromosomal evolution allowed Calochortus to ‘double-up’ its regional radiations, preventing crosses between pairs of clades with overlapping ranges. Floral evolution in Calochortus is an example of consequent radiation, with selection for local diversification in habitat driving secondary specialization of flowers on the range of pollinators and abiotic conditions within each habitat, rather than selection to partition pollinators within habitats driving adaptive radiation.