@article {118,
	title = {A preliminary numerical analysis of the red oak complex in Michigan and Wisconsin USA},
	journal = {Taxon},
	volume = {26},
	year = {1977},
	note = {197865044113Taxa studied: Q. palustris {\textendash} 2 individuals, MI Q. coccinea {\textendash} 4 individuals, OH Q. velutina {\textendash} 4 ind{\textquoteright}ls, MI, WI, IA Q. ellipsoidalis {\textendash} 5 individuals, MI, WI IL (the latter being the syntype from Miami OH herbarium) Q. rubra {\textendash} 7 ind{\textquoteright}ls, MI, WI Putative hybrids: 18 (5 WI, 13 MI) Methods 20 morphological characters chosen based on their utitlity for distinguishing taxa 2nd dataset of 18 ratios derived from the above 1. Datasets used to produce a cha4racter-by-character correlation matrix, subject to PCA. OTUs then projected onto principal components. 2. Directed minimum spanning graph superimposed over points. Results 1. Q. rubra and Q. coccinea form the most distinct clusters 2. Q. palustris (2 OTUs) forms a tight cluster, but oddly, the nearest neighbor of each is a Q. rubra (in the raw dataset) 3. Hybrids in the raw dataset are centrally located among the species clusters, mostly closest to Q. ellipsoidalis, Q. velutina, and Q. palustris. In the transformed data, all putative hybrids fall between the Q. ellipsoidalis and Q. velutina clusters.},
	month = {1977},
	pages = {399-407},
	abstract = {Individuals representing 5 taxa [Quercus coccinea, Q. ellipsoidalis, Q. palustris, Q. rubra and Q. velutina] and numerous unidentified OTU [operational taxonomic unit] of red oaks native to the western Great Lakes region of the USA were examined through principal components analysis. Two data sets, 1 consisting of 20 untransformed characters and 1 in which various characters were redefined as ratios, were employed for comparative analysis. Although minor differences are noted, the 2 data sets provide essentially the same view of the relationships between the included OTU. The 5 taxa appear to form more or less discrete groups with the unidentified OTU occupying positions of intermediacy. The results support previous conclusions that extensive hybridization occurs among the red oaks of this geographic region.},
	keywords = {-HYBRIDIZATION, -QUERCUS-VELUTINA-OPERATIONAL-TAXONOMIC-UNIT-PRINCIPAL-COMPONENTS-ANALYSIS, -Taxonomy, [26070-] Fagaceae-, Angiospermae-, Biogeography-: Population-Studies, Computational-Biology, Dicots-, Dicotyledones-, Fagaceae-: Angiosperms-, Genetics-, Mathematical-Biology:, Plantae-, Plants-, Population-Genetics: Population-Studies, QUERCUS-COCCINEA-QUERCUS-ELLIPSOIDALIS-QUERCUS-PALUSTRIS-QUERCUS-RUBRA, Spermatophyta-, Spermatophytes-, Systematics-and, Vascular-Plants},
	author = {Jensen, R.J.}
}
@article {51,
	title = {Isozyme variation in oaks of the Apostle Islands in Wisconsin: Genetic structure and levels of inbreeding in Quercus rubra and Q. ellipsoidalis (Fagaceae)},
	journal = {American Journal of Botany},
	volume = {80},
	year = {1993},
	note = {199497074468Findings1. No species specific alleles were found 2. Allozyme variation was high, despite small geographic scale 3. Heterozygosity was lower than HW equilibrium. [My question: could this be b/c they were analyzing two spp together? this would produce inflated Het(expected)] 4. Nm for adults = 5.70, low for outcrossing, wind-pollinated, widespread spp 5. Acorn homozygosity ~ 2X adult homozygosity 6. HOWEVER, very low Fst and high genetic similarities suggest high gene flow 7. Likewise, morphological data suggest a genetic cline between mainland and islands This apparent contradiction {\textendash} low heterozygosity suggesting little gene flow; but high genetic identities, low Fst, and morphological intergradation {\textendash} may be a consequence of logging history. "Bottleneck" reproduction may account for lower heterozygosity in all populations.},
	month = {1993},
	pages = {1349-1357},
	abstract = {Isozyme variability was examined in populations representing the red oak complex (Quercus subg. Erythrobalanus) on an island archipelago and adjoining peninsula in Lake Superior, near Bayfield, Wisconsin. A concomitant study of morphometric variation described in the companion manuscript, revealed a continuum in leaf morphology extending from an interior mainland site to the outermost island. The existence of this clinal variation presented an ideal opportunity to examine the genetic structure of a hybrid population along with the putative progenitor species. Dormant leaf bud samples were collected from specimens of Quercus rubra L., Q. ellipsoidalis Hill, and their putative hybrids from three islands and two locations on the peninsula. Acorns were collected from some of these same trees from one peninsula location and two islands. Twelve putative enzyme loci from six enzyme systems were analyzed. Allele frequency data indicated little differentiation between populations. Mean F-ST values for the adult trees and acorns were 0.042 and 0.020. Genetic identities according to Nei ranged from 0.958 to 0.999. Despite these high levels of genetic similarity, the populations appeared to be highly inbred as indicated by positive mean F-IT values of 0.183 and 0.373 for the adult trees and acorns. Estimates of migration rate per generation (Nm) for the adult trees was 5.70, a value that is low when compared to estimates for other plant species with similar life history characteristics.},
	keywords = {-Biophysics, [26070-] Fagaceae-, ALLELE-FREQUENCY, Angiospermae-, Dicots-, Dicotyledones-, Ecology-: Environmental-Sciences, Enzymology-: Biochemistry-and-Molecular, Fagaceae-: Angiosperms-, Genetics-, Nearctic-region, Plantae-, Plants-, Population-Genetics: Population-Studies, POPULATIONS-, Quercus-ellipsoidalis (Fagaceae-), Quercus-rubra (Fagaceae-), Reproduction-, Spermatophyta-, Spermatophytes-, USA-: North-America, Vascular-Plants},
	author = {Hokanson, S.C. and Isebrands, J.G. and Jensen, R.J. and Hancock, J.F.}
}
@article {52,
	title = {Vegetative characters, population variation, and the hybrid origin of Quercus ellipsoidalis},
	journal = {American Midland Naturalist},
	volume = {111},
	year = {1984},
	note = {198478050210Intro Starts with the common supposition that veg. chars are not good for ID{\textquoteright}g spp, but notes that many have recognized lf shape as being useful for ID{\textquoteright}g oak spp even if it is suspect. Jensen, to deal with variability within ind{\textquoteright}ls, has in previous studies relied on (1) foliage exposed to full sunlight and (2) intraindividual averages. Few studies have examined intraindividual patterns of variation. Questions driving the study: Can variation in lf morphology distinguish (1) ind{\textquoteright}ls within a population, (2) taxa within a community, and (3) hybrids from pure individuals. ALSO, (4) is Q. ellipsoidalis a taxon of hybrid origin Methods MLDA (multiple linear discriminant analysis) on 9 lf variables. MLDA differentiates groups by comparing within and among group variances. If w/in tree variation < among-tree variation, then linear discriminant functions should be useful in recognizing trees. Findings 1. Lvs are correctly assigned to their respective trees > 75\% of the time for 18 of 19 populations (N = 7{\textendash}21 trees / pop{\textquoteright}n) 2. Hybridization lowers correct classification rate, b/c hybridization increases within-tree variance. 3. The poorest class{\textquoteright}n rate (45.8\% success) represents type specimens of Q. ellipsoidalis collected by E.J. Hill and Agnes Chase {\textendash} Jensen{\textquoteright}s population 19. My concern (10-26-2006) Looking at Jensen{\textquoteright}s lectotypification article (Jensen 1979), it appears that he analyzed 12 sheets representing 3 trees: 10 sheets of Hill 176, 1895 (collected in different years); 1 sheet of Hill 95, 1896; and 1 sheet of Hill 96, 1896. If so, is the poor classfication rate due to the fact that the within group and among group variances are nearly the same?},
	month = {1984},
	pages = {364-370},
	abstract = {Vegetative characters have been considered unreliable for distinguishing oak taxa. Results of a series of multiple linear discriminant analyses of collections containing 1 or more oak taxa are presented. Leaf characters not only can separate the various taxa, but in the absence of hybridization, each tree in each collection may be recognized as a distinct multivariate entity. Comparison of an analysis of the type materials of Q. ellipsoidalis with the results of other analyses supports the hypothesis that the type population of this species was a hybrid swarm.},
	keywords = {-Genetics: Population-Studies, [26070-] Fagaceae-, Angiospermae-, Dicots-, Dicotyledones-, Ecology-: Environmental-Sciences, Fagaceae-: Angiosperms-, Genetics-, Morphology-, Plantae-, Plants-, Population, Spermatophyta-, Spermatophytes-, STATISTICS-LEAF/, Vascular-Plants},
	author = {Jensen, R.J. and Depiero, R. and Smith, B.K.}
}
