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The Architecture of Infraspecific Differentiation: A Case Study in

The Architecture of Infraspecific Differentiation: A Case Study in Astragalus lentiginosus (Fabaceae). Brian J. Knaus Department of Botany and Plant Pathology Oregon State University Rich Cronn Pacific Northwest Research Station USDA Forest Service, PNW Aaron Liston

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The Architecture of Infraspecific Differentiation: A Case Study in

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  1. The Architecture of Infraspecific Differentiation: A Case Study in Astragalus lentiginosus (Fabaceae). Brian J. Knaus Department of Botany and Plant Pathology Oregon State University Rich Cronn Pacific Northwest Research Station USDA Forest Service, PNW Aaron Liston Department of Botany and Plant Pathology Oregon State University

  2. W.L. Brown Jr. & E.O. Wilson Polytopic races, naming implies a discrete nature. C.R. Darwin R.A. Fisher Variation increases, leading to divergence. Subspecies are geographic races, but this diversity needs to be recorded. E.W. Mayer Why study infra-taxa?

  3. Questions: • Is there a need for infra-taxa? • is there a ‘profound’ amount of diversity that justifies subdivision below the level of species? • Do infra-taxa have ‘natural’ breaks? • Is there an optimal number of infra-taxa?

  4. 5 Floral 4 Fruit 6 Vegetative 15 characters All Continuous

  5. Questions: • Is there a need for infra-taxa? • is there a ‘profound’ amount of diversity that justifies subdivision below the level of species? • Do infra-taxa have ‘natural’ breaks? • Is there an optimal number of infra-taxa?

  6. A.l. var. salinus A.l. var. australis A.l. var. lentiginosus A.l. var. coachellae A.l. var. borreganus A.l. var. variabilis Green Grey A.l. var. lentiginosus A.l. var. australis A.l. var. borreganus White Purple

  7. Mean Monthly Temperature Death Valley, CA Max PRISM value 11.5° C Degrees Celsius ~20 ° C (36 ° F) Gros Ventre Range, WY min PRISM value Day Monthly (1971-2000) PRISM data from Daly et al. (2002).

  8. Questions: • Is there a need for infra-taxa? • is there a ‘profound’ amount of diversity that justifies subdivision below the level of species? • Do infra-taxa have ‘natural’ breaks? • Is there an optimal number of infra-taxa?

  9. Discriminant Function Analysis to Distinguish Barneby’s varieties. Color represents Rydberg’s sections. DF 2 Only Morphology Morphology with Latitude and Longitude DF 1 & 3

  10. Questions: • Is there a need for infra-taxa? • is there a ‘profound’ amount of diversity that justifies subdivision below the level of species? • Do infra-taxa have ‘natural’ breaks? • Is there an optimal number of infra-taxa?

  11. How Many Groups? K-means Clustering: 4 methods Rydberg’s 3 sections (includes A.l. var. palans) Barneby’s 14 varieties

  12. Conclusions: • Is there a need for infra-taxa? A. lentiginosus contains an ‘unreasonable’ amount of morphological diversity. • Do infra-taxa have ‘natural’ breaks? There are no clear breaks – existing taxonomy is ‘good.’ Aspire toward stability in taxonomy. • Is there an optimal number of infra-taxa? Varieties are clinal in nature and can be divided into multiple, equally good groupings.

  13. Thank you!!! Richard Halse (OSC) arranged for herbarium loans and provided support in the herbarium. Specimens: BRY, JEPS, NESH, NY, ORE, OSC, POM, RENO, RM, RSA, UC and WILLU. Nancy Mandel and Randy Johnson (USDA FS, PNW) provided help with statistical analyses. Chris Poklemba (USDA FS, PNW) helped with propagation of A. lentiginosus at the Corvallis FSL.

  14. Looking for a Postdoc? Starting 2008 Brian J. Knaus Department of Botany and Plant Pathology Oregon State University http://oregonstate.edu/~knausb knausb@science.oregonstate.edu

  15. Does Morphology Have Natural Breaks? PC 1 vs. ln Annual Precipitation R2 = 32% p<< 0.05 Residual standard error: 1.833 on 261 degrees of freedom Multiple R-Squared: 0.3229, Adjusted R-squared: 0.3203 F-statistic: 124.5 on 1 and 261 DF, p-value: < 2.2e-16

  16. Does Morphology Have Natural Breaks? PC 2 vs. Frost Free Days R2 = 14% p<< 0.05 Residual standard error: 1.43 on 209 degrees of freedom Multiple R-Squared: 0.1407, Adjusted R-squared: 0.1366 F-statistic: 34.23 on 1 and 209 DF, p-value: 1.872e-08

  17. Principle Components Analysis (correlational matrix) of Barneby’s varieties. Color represents Rydberg’s sections. PC 2 PC 1 & 3

  18. Conclusions: • Is there a need for infra-taxa? • A. lentiginosus contains an ‘unreasonable’ amount of morphological diversity.

  19. How Many Groups? Maximum Likelihood Analysis of Optimal Cluster Number Greatest BIC is flat! • Spherical, equal volume • Spherical, unequal volume • Diagonal equal volume, equal shape • Diagonal varying volume, varying shape • Ellipsoidal, equal volume, shape and orientation. • Ellipsoidal, varying volume, shape and orientation

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