STUDIES IN THE QUERCUS UNDULATA COMPLEX. V. THE TYPE OF QUERCUS UNDULATA

The original material of Quercus undulata Torr. was collected by Edwin James on Major Long's expedition to the Rockies in 1820. The type locality was stated by Torrey as “sources of the Canadian and the Rocky Mountains.” Evidence is here adduced that the type locality is on Ute Creek, a tributary of the Canadian River, in northeastern New Mexico. The site was found to harbor Q, gambelii, Q. grisea, and numerous intermediate hybrid forms. Certain of the latter match the type of Q. undulata quite closely. The type sheet includes three elements—a branchlet regarded as the type, a twig of Q. grisea, and an isolated acorn of Q. havardii. Torrey's new species was illustrated by a figure which does not closely resemble the type, but which is more similar to Q. havardii. The acorn of Q. havardii on the type sheet must have been collected in the Texas Panhandle or western Oklahoma, where Long's party would have encountered this species. In my opinion, Torrey's figure could have been drawn from a specimen collected there, which, except for the isolated acorn, has since been lost.     

STUDIES IN THE QUERCUS UNDULATA COMPLEX. III. THE CONTRIBUTION OF Q. ARIZONICA

Tucker, J. M. (U. California, Davis.) Studies in the Quercus undulata complex. III. The contribution of Q. arizonica . Amer. Jour. Bot. 50(7): 699–708. Illus. 1903.—Of the 7 oak species involved in the Quercus undulata complex, Q. arizonica contributes the least of all. The latter has hybridized with Q. gambelii at a few widely separated localities (listed in Table 1) in central Arizona, and northern Sonora and Chihuahua, Mexico. The putative hybrids (identifiable as Quercus undulata) occur as isolated individuals with the parental species. The parents, although regionally sympatric, are usually ecologically isolated. They differ in a number of morphological characters, 6 of which were analyzed in detail. The resulting data, presented as pietorialized scatter diagrams, demonstrate that the putative hybrids are intermediate, in general. This is taken as evidence of their hybrid nature. Factors limiting hybridization in oaks are discussed. It is speculated that hybridization between Q. arizonica and Q. gambelii has occurred since the postglacial hypsithermal interval.     

STUDIES IN THE QUERCUS UNDULATA COMPLEX. II. THE CONTRIBUTION OF QUERCUS TURBINELLA

Tucker , J. M. (U. California, Davis), W. P. Cottam , and R. Drobnick . Studies in the Quercus undulata complex. II. The contribution of Quercus turbinella. Amer. Jour. Bot. 48(4): 329–339. Illus. 1961.—Quercus undulata has been interpreted as a hybrid complex involving Q. gambelii and several other species, including Q. turbinella (Tucker, 1961). In the present paper, the total distribution of the hybrids between Q. gambelii and Q. turbinella is given. Lacking direct genetic evidence, proof of hybridity is sought in a demonstration of the morphological intermediacy of these putative hybrids. Population samples of both parental species, other samples containing hybrids, and numerous individual hybrids, are analyzed on the basis of 6 differences between the parental species. The data obtained, presented in the form of pictorialized scatter diagrams, clearly show the general intermediacy of the hybrids. Of the various binomials that have been applied to forms in the Q. undulata complex, Quercus pauciloba Rydb. applies to this hybrid. The appropriate change in status (Quercus × pauciloba Rydb.) is made.     

HOW DISCRETE ARE OAK SPECIES? INSIGHTS FROM A HYBRID ZONE BETWEEN QUERCUS GRISEA AND QUERCUS GAMBELII

The white oaks Quercus gambelii and Q. grisea overlap in distribution in New Mexico and Arizona. Within the region of overlap, there are numerous instances of contact between the two taxa. In some areas of contact morphologically, intermediate trees are common, whereas in others, morphologically intermediate trees are rare or absent. We describe a set of RAPD markers that distinguish between the two species and use these markers to examine patterns of gene exchange in an area of contact in the San Mateo Mountains of New Mexico. The markers are highly coincident with morphology and confirm that hybridization between the two species takes place. Despite the occurrence of hybrids, both species remain distinct, even in areas of sympatry, and marker exchange appears to be limited.     

STUDIES IN THE QUERCUS UNDULATA COMPLEX I. A PRELIMINARY STATEMENT

Tucker , John M. (U. California, Davis.) Studies in the Quercus undulata complex. I. A preliminary statement. Amer. Jour. Bot. 48(3): 202–208. Illus. 1961.—The taxonomic history of Quercus undulata, a highly variable, problematic complex of the Southwest, is discussed. Conservatively treated as a single species, it comprises a wide range of forms which at one extreme approach Q. gambelii morphologically, and, at the other, Q. grisea, Q. turbinella, and other species. The postulate was made that Q. undulata had arisen through hybridization between these very different oaks. Field observations and preliminary study of numerous population samples confirm this postulate. (Detailed morphological analyses are in progress.) Seven species have apparently been involved—Q. gambelii (the “common denominator” of the complex) has hybridized in different parts of its range with one or another of the following: Q. arizonica, Q. turbinella, Q. havardii, Q. muehlenbergii, Q. mohriana, and Q. grisea. The latter 6 species are discussed individually, and the extent to which each contributes to the complex, and the area in which this occurs, are indicated.     

From middens to molecules: phylogeography of the piñon pine,Pinus edulis

Aim Data from packrat middens have established a hypothesized historical biogeography of piñon pine, Pinus edulis, including locations of glacial refugia in the south‐western USA and subsequent migration out of the refugia. In this study, we used molecular techniques to test the glacial refugial hypotheses inferred from packrat (Neotoma) midden data for P. edulis. Location South‐western USA. Methods Two fragments of chloroplast DNA (a portion of the matK gene and a portion of the rbcL gene) for a total of 1045 base pairs were amplified and sequenced for 100 individuals. Thirty‐one populations were sampled throughout the range of P. edulis. Phylogenetic analyses included maximum parsimony and maximum likelihood. Results Very little variation existed among the individuals sampled. Four haplotypes were identified. The inferred ancestral haplotype was the most widespread; it was most common in Texas and New Mexico where, with the exception of one individual, it was the only haplotype found. Arizona and Utah populations were more diverse, with almost half of the populations containing two or more haplotypes. The most derived haplotype was most abundant in Arizona. Main conclusions The distribution of haplotypes is geographically informative. Only one haplotype exists in the south‐eastern portion of the range of P. edulis whereas up to four haplotypes are found in other populations, suggesting one of two hypotheses: either all modern populations are descended from a refugial population in central Arizona, or modern populations are descended from two refugial populations, one in central Arizona and another in Texas–southern New Mexico. Interpreting these data in the light of packrat midden data gives more support for the latter hypothesis.     

A NEW SPECIES OF BLACK OAK (QUERCUS,SUBG. ERYTHROBALANUS,FAGACEAE) FROM THE SIERRA MADRE OCCIDENTAL,MEXICO

Quercus mcvaughii is described as a new species of black oak (subgenus Erythrobalanus) from the Sierra Madre Occidental, in northern Durango and western Chihuahua, Mexico. It is most closely related to the more southern Q. crassifolia. Sessile or subsessile hairs, usually of different sizes, on the abaxial leaf surface distinguish Q. mcvaughii from Q. crassifolia, where hairs are similar in size and conspicuously stipitate. A key is provided for distinguishing similar species in the region. Intergradation of Q. mcvaughii with Q. crassifolia, Q. hypoleucoides, and Q. sideroxyla is reported.     

Factors controlling the distribution of a subtropical corn borer,Diatraea grandiosella (Lepidoptera: Pyralidae)

During this century the southwestern corn borer, Diatraea grandiosella (Lepidoptera: Pyralidae), has extended its range from subtropical Mexico into the United States, below 38° N latitude. This maize‐feeding insect is now found from Arizona east to Alabama and north to Kansas, Missouri, and Tennessee. The species has adapted to the shorter growing seasons, longer summer daylengths, and lower winter temperatures present in the southern US than are present in Mexico. Life history, morphological, and behavioral traits were compared for populations of D. grandiosella from southeastern Missouri and southcentral Mexico and revealed differentiation in a suite of characters, some of which show clear adaptation to a northern climate while others are obviously less adaptive. An electrophoretic comparison of enzymes from D. grandiosella from the central portion of its range in the US and from a population from southcentral Mexico indicated that considerable genetic differentiation has occurred. Quantitative genetic studies should be undertaken on the original and dispersed populations to differentiate between those characters that have been directly responsible for the adaptation of this insect to northern maize‐growing regions and those that have changed merely due to genetic correlations with characters undergoing selection. Data from such studies, together with available information about the dispersal of this insect, should provide insight into factors regulating the movement of tropical insects into temperate regions.     

A three-trophic-level analysis of the effects of plant hybridization on a leaf-mining moth

We investigated relationships between host plant hybridization in the Quercus grisea x Q. gambelii species complex and the distribution and performance of a leaf-mining moth in the genus Phyllonorycter. In 2 years at two sites Phyllonorycter densities were lowest on Q. grisea and increased through the categories of hybrid host plants to Q. gambelii. Direct host plant effects on Phyllonorycter performance were consistent with Phyllonorycter distribution; unexplained mortality of larvae in the mines, which is often associated with direct plant effects, decreased from Q. grisea through the hybrids to Q. gambelii. Plant hybridization influenced parasitism of Phyllonorycter. Parasitism was density dependent, and across all densities was higher on Q. grisea and Q. gambelii than on hybrid host plants.     

Another look at Hymenoxys subgenus Plummera (Asteraceae: Heliantheae: Gaillardiinae) from Arizona and New Mexico

The recent merger ofPlummera intoHymenoxys is followed here. The two previously recognized species ofPlummera are here treated as a single polymorphic species ofHymenoxys, H. ambigens, consisting of three varieties: var.ambigens from the Mescal, Santa Teresa, and Pinaleno Mountains of southeastern Arizona; var.floribunda from the Chiricahua, Dos Cabezas, Dragoon, Little Dragoon, and Mule Mountains of southeastern Arizona; and var.neomexicana described here from the Animas and Peloncillo Mountains of southwestern New Mexico.     

Triploid and tetraploid hybrids from diploid x tetraploid crosses in Grindella (compositae)

Crosses between the diploids G. oxylepis var. eligulata Steyermark (Mexico) and G. havardii Steyermark (New Mexico) and the tetraploid G. aphanactis Rydb. (New Mexico) were made. With G. aphanactis as the pistillate parent and G. havardii as the pollen parent a triploid hybrid was obtained in which the maximum meiotic configuration observed was 6m. The plant was 10 % fertile. Two triploid hybrid plants were also obtained when G. aphanactis was used as the pistillate parent and G. oxylepis var. eligulata was the pollen parent. One plant was about 20 % fertile and the other had a maximum configuration of 3_II + 4_III. The reciprocal cross produced a tetraploid which had a maximum configuration of 6_II + 3_IV and was 8 % fertile. The tetraploid plant undoubtedly resulted from the union of an unreduced gamete from the 2n parent and a normally reduced gamete from the tetraploid. Morphology of the hybrids was usually intermediate when compared with the parental species, although some characters in the triploids were those of the diploid parent. Chromosome end arrangements of the respective genomes and putative pairing relationships are presented and phylogenetic implications are discussed. It is concluded that G. aphanactis is more closely related to G. havardii than to G. oxylepis var. eligulata.     

A new species of Cymopterus (Apiaceae) from the Rocky Mountain region, U.S.A.

Cymopterus constancei is described as new from mostly western portions of Wyoming, Colorado, and New Mexico and from eastern Utah and Arizona. It has been confused withC. bulbosus A. Nelson but differs in several features of its bractlets, phenology, and habitat. The novelty is among the earliest of the native flora to bloom and is quite uniform morphologically. The number of collections encountered exceeds 200, a fourfold increase, in the past 22 years.     

Mitochondrial DNA Variation and Phylogeography of the Ferruginous Pygmy-Owl (Glaucidium brasilianum)

Sequences from the mitochondrial cytochrome b gene were used to examine patterns of variation within and among populations of the ferruginous pygmy-owl (Glaucidium brasilianum) from both North America (including populations from Mexico) and South America. As currently conceived, G. brasilianum is paraphyletic, with North American and South American clades representing two distinct groups that should be recognized as the distinct species G. ridgwayi and G. brasilianum, respectively. Within the G. ridgwayi clade, populations from Arizona, Sonora, and Sinaloa are genetically distinct and share no mitochondrial haplotypes with populations occurring in Texas and other regions of Mexico. According to nested clade analysis this separation may be the consequence of past fragmentation that predates the origin of the Sonora desert. In addition, gene flow between the Arizona/Sonora/Sinaloa populations and the Texas/other Mexico populations is practically nonexistent, with estimates being approximately one individual every 10 generations. Collectively, these data suggest that the Arizona/Sonora/Sinaloa clade should be recognized as either a distinct subspecies or phylospecies from the group containing populations in Texas and the remainder of Mexico. These data should be used as guidelines for pygmy-owl recovery and conservation, as they meet the recommendations of task 3 of the pygmy-owl recovery plan that lists genetic data as essential information for pygmy-owl management.     

HERMAPHRODITIC FLOWERING IN GAMBEL OAK

Gambel oak (Quercus gambelii Nutt.) is normally monoecious, flowering once a year in spring. In Utah, August 1978, several individuals were observed producing hermaphroditic flowers in riparian habitats. This unusual event was preceded by a general freeze of male catkins in May which resulted in low acorn production. In 1979 the same individuals flowered normally, with no evidence of freeze damage or hermaphroditic flowers being observed. Acorns were produced on these individuals in both years. It is suggested that hermaphroditic flowering in the Fagaceae is an ancestral condition, still present in the genome, but normally suppressed, which may be evoked by unusual environmental conditions.     

Host Preference Among Populations of Drosophila mojavensis (Diptera: Drosophilidae) that Use Different Host Cacti

Previous studies have suggested that all populations of cactophilic Drosophila mojavensis prefer pitaya agria cactus, Stenocereus gummosus, over all other potential hosts for feeding and breeding, including populations that inhabit areas where no agria grows. We sampled five geographically isolated populations of D. mojavensis from nature to assess host choice within and between populations. Host choice tests were performed in a laboratory olfactometer by allowing adult D. mojavensis to choose between plumes of synthetic volatile cocktails of two widespread host cacti. Overall, each population showed significant preference for agria volatiles with one exception: a mainland Sonora population that uses organ pipe cactus in nature exhibited preference for organ pipe volatiles, suggesting a possible shift in host preference. The degree of preference for agria volatiles was greatest in a population from southern California that use California barrel cactus as a host. Since southern Californian populations of D. mojavensis are thought to be derived from those in Baja California, preference for agria volatiles is considered a retained ancestral trait. Three populations from Baja California and mainland Mexico that use agria in the wild expressed lower, but similar preferences for agria volatiles. Because populations of D. mojavensis are ancestral to those in mainland Mexico, Arizona, and California, the shift from agria to alternate hosts has not been accompanied by strong changes in host preference behavior.     

Genetic discontinuity among regional populations of <Emphasis Type="Italic">Lophelia pertusa</Emphasis> in the North Atlantic Ocean

Knowledge of the degree to which populations are connected through larval dispersal is imperative to effective management, yet little is known about larval dispersal ability or population connectivity in Lophelia pertusa, the dominant framework-forming coral on the continental slope in the North Atlantic Ocean. Using nine microsatellite DNA markers, we assessed the spatial scale and pattern of genetic connectivity across a large portion of the range of L. pertusa in the North Atlantic Ocean. A Bayesian modeling approach found four distinct genetic groupings corresponding to ocean regions: Gulf of Mexico, coastal southeastern U.S., New England Seamounts, and eastern North Atlantic Ocean. An isolation-by-distance pattern was supported across the study area. Estimates of pairwise population differentiation were greatest with the deepest populations, the New England Seamounts (average F _ST = 0.156). Differentiation was intermediate with the eastern North Atlantic populations (F _ST = 0.085), and smallest between southeastern U.S. and Gulf of Mexico populations (F _ST = 0.019), with evidence of admixture off the southeastern Florida peninsula. Connectivity across larger geographic distances within regions suggests that some larvae are broadly dispersed. Heterozygote deficiencies were detected within the majority of localities suggesting deviation from random mating. Gene flow between ocean regions appears restricted, thus, the most effective management scheme for L. pertusa involves regional reserve networks.     

Supernumerary chromosomes of the harvest mouse,Reithrodontomys megalotis

Chromosomes were analyzed from 282 field captured and 76 laboratory specimens of the Western Harvest Mouse, Reithrodontomys megalotis. The supernumerary chromosomes found in this species varied from 0 to 7 causing a variation in diploid number of from 42 to 49 with the modal class being 2n=44. The relative frequency of various numbers varied between populations, which were taken from Arizona, California, Nebraska, New Mexico and Utah. Laboratory breeding experiments and cytological evidence indicate differences in the rate of non-disjunction is responsible for interpopulational variation. A hypothesis is suggested to explain this variation as it relates to the evolution and zoogeography of the species.     

Interactions between host plants,endophytic fungi,and a phytophagous insect in an oak (Quercus grisea x Q. gambelii) hybrid zone

We examined interactions between host plants, endophytic fungi, and leaf-mining moths (Phyllonorycter sp.) in an oak (Quercus grisea x Q. gambelii) hybrid zone. The community of endophytic fungi and two common endophyte species examined responded to host plant hybridization. Total fungal frequency (TFF) and frequency of Gnomonia cerastis were lowest on hosts resembling Q. grisea, and increased linearly towards those resembling Q. gambelii. In contrast, Coccochorella quercicola was most frequently isolated from Q. grisea-like hosts and decreased in frequency across hybrids towards Q. gambelii. Frequency of G. cerastis and TFF covaried with Phyllonorycter density across the hybrid zone, but direct effects of endophytes on Phyllonorycter density were not detected. Associations between endophytes and unexplained mortality of Phyllonorycter varied according to endophyte species and state of Phyllonorycter development. In the sap-feeding stage, unexplained mortality was negatively associated with TFF and frequencies of Hormonema sp. and Preussia funiculata; whereas, in the tissue-feeding stage, unexplained Phyllonorycter mortality was positively associated with G. cerastis frequency. Three-way interactions between plant hybridization, endophytic fungi, and the insect herbivore were not significant.     

CRYPTOENDOLITHIC ALGAL COMMUNITIES OF THE COLORADO PLATEAU1

Eighteen taxa, including representatives of both eukaryotic and prokaryotic genera, were isolated from below the surface of eight sandstones in four semi-desert and cold temperate biomes of northern Arizona, southern Utah and Western New Mexico. The algae occurred as uniform well defined bands in light-colored sandstones and also as scattered patches in dark sandstones. The algal communities varied in generic composition, chlorophyll a content, and location within the different sandstones. Biomass, estimated by chlorophyll a content, was approximately two to twenty-fold greater than reported for cryptoendolithic algal bands in a cold desert habitat. The widespread distribution of certain algae in endolithic habitats of the Colorado Plateau and their presence in rocks at quite distant locations suggests that the endolithic habitat may he utilized by algae whenever it provides more favorable conditions than the surrounding surfaces.     

UNDERGROUND SYSTEMS OF GAMBEL OAK (QUERCUS GAMBELII) IN CENTRAL UTAH

Excavation to a depth of 1 m of a 3 × 4 m portion of a clone of Quercos gambelii revealed the presence of a massive underground system of lignotubers, interconnecting rhizomes and roots. Lignotubers comprised the greatest proportion (72%) of the total below ground biomass (81 t/ha). Lignotubers are distinctive in appearance: they are an enlarged stemlike structure with numerous clusters of adventitious buds on the surface. Anatomically, they are comparable to the above ground stems with growth rings. Lignotubers are lobed and distorted, giving the appearance of a burl. Rhizomes are round to I-beam in shape with a star-shaped pith, distinct annual rings, bud traces, and branch gaps. There were also clusters of adventitious buds on rhizomes, although not as dense as those on the lignotubers. Roots are oval in cross section with discernible growth rings, no pith, and no bud traces.