The Architecture of The Architecture of Infraspecific Differentiation: A Infraspecific Differentiation: A

Case Study in Case Study in Astragalus lentiginosusAstragalus lentiginosus

(Fabaceae).(Fabaceae).Brian J. KnausBrian J. Knaus

Department of Botany and Plant PathologyDepartment of Botany and Plant PathologyOregon State UniversityOregon State University

Rich CronnRich CronnPacific Northwest Research StationPacific Northwest Research Station

USDA Forest Service, PNWUSDA Forest Service, PNW

Aaron ListonAaron ListonDepartment of Botany and Plant PathologyDepartment of Botany and Plant Pathology

Oregon State UniversityOregon State University

Why studyinfra-taxa?

Variation increases, leading to divergence.

C.R. Darwin

R.A. Fisher

W.L. Brown Jr. & E.O. WilsonPolytopic races,

naming implies a discrete nature.

E.W. Mayer

Subspecies are geographic races, but this diversity needs to be recorded.

Questions:

1. Is there a need for infra-taxa?• is there a ‘profound’ amount of diversity that

justifies subdivision below the level of species?

2. Do infra-taxa have ‘natural’ breaks?

3. Is there an optimal number of infra-taxa?

Family Scientific Name Infra-rankcoun

t

FabaceaeAstragalus lentiginosus var. 35

PolygonaceaeEriogonum umbellatum var. 30

Asteraceae Ericameria nauseosa ssp. & var. 22

AsteraceaeHymenopappus filifolius var. 13

Malvaceae Sidalcea malviflora ssp. 13

Polygonaceae Eriogonum nudum var. 13

Asteraceae Ericameria parryi var. 12

Asteraceae Eriophyllum lanatum var. 12

Brassicaceae Lepidium montanum var. 12

Asteraceae Achillea millefolium var. 11

Caryophyllaceae Arenaria congesta var. 11

Fabaceae Trifolium longipes ssp. 11

Rosaceae Potentilla glandulosa ssp. 11

Variety

Rydberg’s

SectionsDistributi

on

Barneby's

Sample

Barneby's

Specimens

Current Sample

A. l. var. borreganus

Coulteriana

widespread 31 4 19

A. l. var. coachellae

Coulteriana endemic 34 2 20

A. l. var. kennedyi

Coulteriana

widespread 31 3 19

A. l. var. palansCoulteriana

widespread 40 9 20

A. l. var. variabilis

Coulteriana

widespread 114 9 21

A. l. var. araneosus Diphysa

widespread 39 8 20

A. l. var. chartaceus Diphysa

widespread 55 8 10

A. l. var. diphysus Diphysa

widespread 66 10 16

A. l. var. floribundus

Lentiginosa

widespread 26 2 14

A. l. var. fremontii

Lentiginosa

widespread 101 14 21

A. l. var. ineptusLentiginosa endemic 23 2 21

A. l. var. lentiginosus

Lentiginosa

widespread 73 3 13

A. l. var. salinusLentiginosa

widespread 80 10 20

A. l. var. scorpionis

Lentiginosa endemic 26 1 10

14 varieties 739 85 244

Character Units

Floral  

peduncle length 0.5 mm

Fl axis in fruit 0.5 mm

keel length(mm) 0.5 mm

calyx tooth length 0.5 mm

calyx tube length 0.5 mm

Fruit  

pod length 0.5 mm

pod height 0.5 mm

pod valve thickness0.01 mm

beak length 0.5 mm

Vegetative  

Stem internode length 0.5 mm

Leaf rachis length 0.5 mm

Leaf petiole length 0.5 mm

Leaflet number n > 7

Leaflet width 0.5 mm

Leaflet length 0.5 mm

5 Floral

4 Fruit

6 Vegetative

15 characters

All Continuous

Questions:

1. Is there a need for infra-taxa?• is there a ‘profound’ amount of diversity that

justifies subdivision below the level of species?

2. Do infra-taxa have ‘natural’ breaks?

3. Is there an optimal number of infra-taxa?

A.l. var. australis

A.l. var. borreganus

A.l. var. coachellae

A.l. var. lentiginosus

A.l. var. salinus

A.l. var. variabilis

GreenGreen GreyGrey

A.l. var. lentiginosus A.l. var. australis A.l. var. borreganus

WhiteWhite PurplePurple

0 100 200 300

-10

01

02

03

0

Monthly (1971-2000) PRISM data from Daly et al. (2002).

11.5° C

~20 ° C

(36 ° F)

Mean Monthly Temperature

Day

Deg

rees

Cels

ius

Death Valley, CA

Max PRISM value

Gros Ventre Range, WY

min PRISM value

Questions:

1. Is there a need for infra-taxa?• is there a ‘profound’ amount of diversity that

justifies subdivision below the level of species?

2. Do infra-taxa have ‘natural’ breaks?

3. Is there an optimal number of infra-taxa?

Discriminant Function Analysis to Distinguish Barneby’s varieties. Color represents Rydberg’s

sections.

Only Morphology Morphology with Latitude and Longitude

DF

2

DF 1 & 3

Questions:

1. Is there a need for infra-taxa?• is there a ‘profound’ amount of diversity that

justifies subdivision below the level of species?

2. Do infra-taxa have ‘natural’ breaks?

3. Is there an optimal number of infra-taxa?

0 5 10 15 20 25 30

40

60

80

10

01

20

Number of Groups

With

in G

rou

p S

um

of S

qu

are

s

Barneby’s 14 varieties

Rydberg’s 3 sections

(includes A.l. var. palans)

How Many Groups?

K-means Clustering: 4 methods

Conclusions:1. Is there a need for infra-taxa?

A. lentiginosus contains an ‘unreasonable’ amount of morphological diversity.

2. Do infra-taxa have ‘natural’ breaks? There are no clear breaks – existing taxonomy is

‘good.’ Aspire toward stability in taxonomy.

3. Is there an optimal number of infra-taxa?Varieties are clinal in nature and can be divided

into multiple, equally good groupings.

Thank you!!!Thank you!!!Richard Halse (OSC) Richard Halse (OSC) arranged for arranged for herbarium loans and provided support herbarium loans and provided support in the herbarium.in the herbarium.

Specimens: BRY, JEPS, NESH, NY, Specimens: BRY, JEPS, NESH, NY, ORE, OSC, POM, RENO, RM, RSA, ORE, OSC, POM, RENO, RM, RSA, UC UC andand WILLU. WILLU.

Nancy MandelNancy Mandel and and Randy JohnsonRandy Johnson (USDA FS, PNW) provided help with (USDA FS, PNW) provided help with statistical analyses. statistical analyses.

Chris PoklembaChris Poklemba (USDA FS, PNW) (USDA FS, PNW) helped with propagation of helped with propagation of A. A. lentiginosuslentiginosus at the Corvallis FSL. at the Corvallis FSL.

Looking for a Postdoc?Looking for a Postdoc?Starting 2008Starting 2008

Brian J. KnausBrian J. KnausDepartment of Botany and Plant Department of Botany and Plant

PathologyPathologyOregon State UniversityOregon State University

http://oregonstate.edu/~knausbhttp://oregonstate.edu/~knausbknausb@science.oregonstate.eduknausb@science.oregonstate.edu

Residual standard error: 1.833 on 261 degrees of freedomMultiple R-Squared: 0.3229, Adjusted R-squared: 0.3203 F-statistic: 124.5 on 1 and 261 DF, p-value: < 2.2e-16

Estimate Std. Error t value Pr(>|t|)

(Intercept) -11.3768 1.0259 -11.09 <2e-16

IV 2.0828 0.1867 11.16 <2e-16

Does Morphology Have Natural Breaks?

PC 1 vs. ln Annual Precipitation

4.5 5.0 5.5 6.0 6.5 7.0

-6-4

-20

24

6

ln Annual Precipitation 1971-2000 (mm)

PC

1

R2 = 32%

p<< 0.05

Residual standard error: 1.43 on 209 degrees of freedomMultiple R-Squared: 0.1407, Adjusted R-squared: 0.1366 F-statistic: 34.23 on 1 and 209 DF, p-value: 1.872e-08

Estimate Std. Error t value Pr(>|t|)

(Intercept) -2.363274 0.387174 -6.104 4.96e-09

IV 0.010144 0.001734 5.850 1.87e-08

Does Morphology Have Natural Breaks?

PC 2 vs. Frost Free Days

50 100 150 200 250 300 350

-4-3

-2-1

01

23

Annual Frost Free Days 1971-2000

PC

2R2 = 14%

p<< 0.05

Principle Components Analysis (correlational matrix) of Barneby’s varieties. Color represents

Rydberg’s sections.

PC

2

PC 1 & 3

Conclusions:

– Is there a need for infra-taxa?• A. lentiginosus contains an

‘unreasonable’ amount of morphological diversity.

How Many Groups?Maximum Likelihood Analysis of Optimal

Cluster Number

Greatest BIC is flat!

1. Spherical, equal volume2. Spherical, unequal volume3. Diagonal equal volume, equal shape4. Diagonal varying volume, varying shape5. Ellipsoidal, equal volume, shape and

orientation.6. Ellipsoidal, varying volume, shape and

orientation

1

1

11

1 1 1 1 1

2 4 6 8

10

00

15

00

20

00

25

00

30

00

number of clusters

BIC

2

2

2

22

2 2 2 2

3

3

3

3

3 3 3 3 3

4

4

4

4 4 44

44

5 5 5 55 5

5 5 56

6

6

6

6

6

6