Supplementary Table 5 |Crossability indices (CIs) in plants.

GROUP
Division
Family / Genus / Reprod. Barrier / 1No. Crosses / Mean CI / Reference
SEED PLANTS
Angiosperms
Acanthaceae / Aphelandra / F1 seed set / 57 / 0.18 / McDade & Lundberg 1982
Araceae / Anthurium / F1 pollen viability / 10 / 0.43 / Marutani et al. 1993
Asclepidaceae / Asclepias / F1 seed set / 4 / 0.19 / Wyatt et al. 1998
Asteraceae / Antennaria / F1 pollen viability / 8 / 0.66 / Bayer 1985
Asteraceae / Argyranthemum / F1 pollen viability / 1 / 0.74 / Brochmann et al. 2000
Asteraceae / Bidens / F1 seed set / 3 / 0 / Hart 1979
Asteraceae / Calendula / F1 seed set / 10 / 0.73 / Heyn & Joel 1983
Asteraceae / Carthamus / Total postzygotic isolation / 11 / 0.41 / Schank & Knowles 1964; Khidir & Knowles 1970
Asteraceae / Cirsium / F1 pollen viability / 1 / 0.07 / Bloom 1977
Asteraceae / Eriophyllum / F1 pollen viability / 9 / 0.20 / Mooring 2002
Asteraceae / Flaveria / F1 pollen viability / 16 / 0.38 / Powell 1978
Asteraceae / Grindelia / F1 pollen viability / 14 / 0.37 / Dunford 1970a
Asteraceae / Helenium / F1 pollen viability / 1 / 0.64 / Knox et al. 1995
Asteraceae / Helianthus / Total postzygotic isolation or F1 pollen viability or F1 seed set / 51 / 0.15 / Chandler et al. 1986; Lai et al. 2005; Long 1960
Asteraceae / Lactuca / Total postzygotic isolation / 3 / 0.01 / De Vries 1990
Asteraceae / Lasthenia / F1 pollen viability / 11 / 0.54 / Ornduff 1966
Asteraceae / Leucanthemum / F1 pollen viability / 14 / 0.61 / Wilcox 1982
Asteraceae / Machaeranthera / F1 pollen viability / 1 / 0.48 / Arnold & Jackson 1978
Asteraceae / Parthenium / F1 pollen viability / 3 / 0.22 / Hashemi et al. 1986
Asteraceae / Sartwellia / F1 pollen viability / 1 / 0.49 / Powell 1978
Asteraceae / Stephanomeria / F1 pollen viability / 3 / 0.08 / Gottlieb 1971
Asteraceae / Tetramolopium / F1 pollen viability / 21 / 0.92 / Lowrey 1986
Asteraceae / Tragopogon / Total postzygotic isolation / 22 / 0.13 / Fahselt et al. 1976
Asteraceae / Vernonia / F1 pollen viability / 22 / 0.51 / Jones 1976
Asteraceae / Zinnia / F1 pollen viability / 11 / 0.65 / Torres 1962
Campanulaceae / Campanula / Total postzygotic isolation / 6 / 0.25 / Nyman 1991
Caryophyllaceae / Petrorhagia / F1 pollen viability / 4 / 0.16 / Thomas & Murray 1981
Caryophyllaceae / Schiedea / Total postzygotic isolation / 26 / 0.90 / Weller et al. 2001
Caryophyllaceae / Silene / F1 pollen viability / 49 / 0.14 / Kruckeberg 1961; Prentice 1978
Chenopodiaceae / Atriplex / F1 pollen viability / 14 / 1.04 / Gustafsson 1973
Chenopodiaceae / Chenopodium / F1 pollen viability or F1 viability / 14 / 0.33 / Wilson 1980
Crassulaceae / Echeveria / F1 pollen viability / 9 / 0.18 / Uhl 1976
Crassulaceae / Sedum / Total postzygotic isolation or F1 pollen viability / 28 / 0.26 / Uhl 1976; Denton 1984
Cucurbitaceae / Cucumis / F1 pollen viability / 12 / 0.28 / Singh & Yavada 1984
Cyperaceae / Carex / F1 seed set + seed germ. / 7 / 1.19 / Whitkus 1988
Ericaceae / Vaccinium / F1 fruit set / 11 / 0.76 / Vander Kloet & Dickinson 1999
Euphorbiaceae / Jatropha / Total postzygotic isolation / 12 / 0.23 / Dehgan 1984
Fabaceae / Arachis / F1 pollen viability / 10 / 0.25 / Stalker et al. 1991
Fabaceae / Lens / Total postzygotic isolation / 6 / Ladizinsky et al. 1984
Fabaceae / Leucaena / F1 seed set / 115 / 0.17 / Sorensson & Brewbaker 1994
Fabaceae / Lupinus / Total postzygotic isolation / 1 / 0.03 / Pazy et al. 1981
Fabaceae / Medicago / F1 pollen viability / 4 / 0.35 / Lesins et al. 1971
Fabaceae / Melilotus / F1 pollen viability / 1 / 0.43 / Jaranowski 1961
Fabaceae / Prosopis / F1 pollen viability / 1 / 0.60 / Naranjo et al. 1984
Fagaceae / Quercus / F1 seed set / 1 / 0.01 / Rushton 1977
Fumariaceae / Dicentra / F1 pollen viability / 3 / 0.33 / Stern & Ownbey 1971
Geraniaceae / Pelargonium / F1 pollen viability / 1 / 0.90 / Albers & Van Der Walt 1992
Gesneriaceae / Rechsteineria / F1 pollen viability / 11 / 0.54 / Clayberg 1968
Gesneriaceae / Sinningia / F1 pollen viability / 7 / 0.21 / Clayberg 1968
Hyacinthaceae / Ornithogalum / F1 seed set or F1 seed germination / 26 / 0.76 / Moret 1987; van Raamsdonk 1985
Hydrophyllaceae / Hydrophyllum / F1 seed set / 28 / 0.01 / Beckmann 1979
Iridaceae / Crocus / F1 seed set / 6 / 0.35 / Chichiricco 1996
Iridaceae / Iris / Total postzygotic isolation / 31 / 0.99 / Avishai & Zohary 1980
Lamiaceae / Agastache / F1 pollen viability / 48 / 0.21 / Vogelmann 1985
Lamiaceae / Hedeoma / F1 pollen viability / 25 / 0.15 / Irving et al. 1979
Lauraceae / Kalmia / Total postzygotic isolation / 14 / 0.09 / Jaynes 1968
Liliaceae / Calochortus / F1 pollen viability / 1 / 0.86 / Ness et al. 1990
Malvaceae / Hibiscus / F1 seed set / 2 / 0.90 / Klips 1995
Onagraceae / Boisduvalia / Total postzygotic isolation / 6 / 0.01 / Seavey 1992
Onagraceae / Clarkia / Total postzygotic isolation or F1 seed set / 17 / 0.073 / Vasek 1964; Small 1971
Onagraceae / Gaura / Total postzygotic isolation or F1 pollen viability / 19 / 0.85 / Carr et al. 1986a, 1986b, 1988
Onagraceae / Oenothera / F1 pollen viability / 1 / 0.67 / Ellstrand & Levin 1980
Orchidaceae / Bulbophyllum / F1 seed set / 3 / 0.45 / Borba et al. 1999
Orchidaceae / Pleurothallis / F1 seed set / 9 / 0.80 / Borba et al. 2001
Orchidaceae / Satyrium / F1 seed set + seed mass / 3 / 0.77 / Ellis & Johnson 1999
Papaveraceae / Eschscholzia / F1 pollen viability / 1 / 0.86 / Clark 1978
Plumbaginaceae / Armeria / F1 pollen viability / 1 / 0.67 / Feliner et al. 1996
Plumbaginaceae / Limonium / F1 pollen viability / 1 / 0.80 / Dawson & Ingrouille 1995
Poaceae / Lolium / F1 seed set / 6 / 0.84 / Terrell 1966; Naylor 1960
Poaceae / Oryza / Total postzygotic isolation / 1 / 0.82 / Gong et al. 2000
Poaceae / Roegneria / Total postzygotic isolation / 1 / <0.01 / Zhou et al. 1999
Poaceae / Triticum / F1 seed set / 6 / 0.84 / Johnson & Dhaliwal 1976
Poaceae / Zizania / Total postzygotic isolation / 1 / 0.081 / Duvall & Biesboer 1988
Polemoniaceae / Eriastrum / F1 seed set / 2 / 0.09 / Brunell & Whitkus 1999
Polemoniaceae / Gilia / Total postzygotic isolation / 50 / 0.09 / Grant 1960, 1964
Polemoniaceae / Linanthus / Total postzygotic isolation / 6 / 0.03 / Patterson 1980
Polemoniaceae / Phlox / Total postzygotic isolation or F1 seed set / 6 / 0.36 / Levin 1963, 1966, 1967
Portulaceae / Claytonia / F1 pollen viability / 1 / 0.06 / Doyle & Doyle 1988
Ranunculaceae / Aquilegia / Total postzygotic isolation / 27 / 0.41 / Prazmo 1965
Ranunculaceae / Ranunculus / F1 pollen viability / 1 / 0.267 / Okada 1984
Rhamnaceae / Ceanothus / F1 pollen viability / 8 / 0.99 / Nobs 1963
Rubiaceae / Ernodea / F1 seed set / 6 / 0.73 / Negron-Ortiz & Hickey 1996
Salicaceae / Salix / Total postzygotic isolation / 11 / 0.11 / Mosseler 1990
Saxifragaceae / Heuchera / Total postzygotic isolation / 19 / 0.58 / Wells 1979
Saxifragaceae / Saxifraga / Total postzygotic isolation / 1 / 0.36 / Gugerli 1997
Scrophulariaceae / Lophospermum / Total postzygotic isolation or F1 seed set / 19 / 0.18 / Elisens 1989
Scrophulariaceae / Mabrya / Total postzygotic isolation or F1 seed set / 10 / 0.06 / Elisens 1989
Scrophulariaceae / Maurandya / Total postzygotic isolation / 6 / 0.43 / Elisens 1989
Scrophulariaceae / Mimulus / Total postzygotic isolation / 1 / 0.16 / Ramsey et al. 2003
Solanaceae / Cyphomandra / F1 seed set and/or pollen viability / 22 / 0.01 / Bohs 1991
Solanaceae / Physalis / F1 seed set / 3 / 0.68 / Sullivan 1985
Solanaceae / Solanum / Total postzygotic isolation or F1 pollen viability / 21 / 0.27 / Grun et al. 1961; Schilling & Heiser 1979
Stylidiaceae / Stylidum / F1 seed set / 1 / 2.96 / Willis & Ash 1990
Thymelaceae / Wikstroemia / F1 pollen viability / 11 / 0.97 / Mayer 1991b
Verbenaceae / Glandularia / F1 pollen viability / 4 / 0.24 / Solbrig et al. 1968
Verbenaceae / Verbena / F1 seed set / 6 / 0.37 / Barber 1982
Zygophyllaceae / Larrea / Total postzygotic isolation / 1 / 0.16 / Yang et al. 1977
SEED PLANTS
Gymnosperms
Pinaceae / Picea / F1 seed set or F1 seed germination / 2 / 0.09 / Major et al. 2005
Pinaceae / Pinus / F1 pollen viability / 1 / 0.59 / Righter & Stockwell 1949
FERNS & FERN ALLIES
ferns
Aspleniaceae / Asplenium / hybrid spore abortion / 20 / Brownsey 1977; Shivas 1969
Cyatheaceae / Alsophila / hybrid spore viability / 1 / 1 / Conant & Cooper-Driver 1980
Dryopteridaceae / Dryopteris / hybrid spore viability / 4 / 0.15 / Walker 1961; Walker 1962; Wagner & Chen 1966
Dryopteridaceae / Polystichum / hybrid spore viability / 1 / 0.17 / Mayer & Mesler 1993
Grammitidaceae / Enterosora / hybrid spore viability / 2 / 1 / Bishop & Smith 1992
Osmundaceae / Osmunda / hybrid spore viability / 1 / 0 / Wagner et al. 1978
Pteridaceae / Ceratopteris / hybrid spore viability / 4 / 0.47 / Hickok & Klekowski 1974
Pteridaceae / Pteris / hybrid spore viability / 3 / 0.47 / Walker 1958
Thelypteridaceae / Phegopteris / hybrid spore viability / 1 / 0 / Mulligan et al. 1972
Sphenophytes
Equisetaceae / Equisetum subgenus Equisetum / F1 sporophyte production / 15 / 0.20 / Duckett 1979
Equisetaceae / Equisetum subgenus Hippochaete / F1 sporophyte production / 10 / 0.36 / Duckett 1979
Lycopodiophytes
Lycopodiaceae / Lycopodium / F1 sterility / 2 / 0.0 / Waterway 1986
Bryophytes
Ditrichaceae / Astomiopsis / F1 spore viability / 1 / 0.98 / Delgadillo 1989
Polytrichaceae / Polytrichum / F1 viability / 1 / 0.05 / Van Der Velde & Bijlsma 2004
Sphagnaceae / Sphagnum / hybrid sterility / 1 / 0.47 / Cronberg & Natcheva 2002

1Number of crosses refers to the number of different interspecific cross-combinations that were reported and for which intraspecific crossability data were available.