Ipomopsis

Ipomopsis aggregata ssp. aggregata

Ipomopsis aggregata ssp. aggregata

Ipomopsis is a complex genus of 29 species native to North America and South America.  Ipomopsis aggregata (scarlet gilia) is perhaps the best known species and most taxonomically complex species in the genus.

Phylogeny

Molecular phylogenetic evidence clearly suggests that Ipomopsis is not monophyletic (Porter et al. 2010).  Ipomopsis havardii and I. sonorae are sister to Dayia.  The rest of the genus is sister to Bryantiella or only B. palmeri (see that genus for a discussion of gene discordance therein).  Within Ipomopsis, the first-diverging clade is comprised of the zygomorphic-flowered species of I. effusa, I. guttata, and I. tenuiflora.  The rest of Ipomopsis forms two well-supported clades 1) a clade of mostly long-lived perennials with short corolla tubes and 2) a clade of mostly hummingbird-pollinated biennial or short-lived perennial plants with long-corolla tubes.  Within these clades, monophyly of species is generally well-supported but interspecific relationships are poorly supported (Porter et al. 2010).  This is in part due to discordance between the plastid and nuclear genomes.

Biogeography

Ipomopsis is largely native to arid and high-elevation areas of the Great Plains and southwestern North America.  Ipomopsis rubra occurs along the Coastal Plain. One species, I. gossypifera is native to South America.  Porter et al. (2010) estimate a divergence time of 36.64 + 0.31 mya for the crown of Ipomopsis (excluding I. havardii and I. sonorae) and a divergence time of 15.97 + 0.25 mya for the I. aggregata species complex. However, these dates must be interpreted with caution as a more reasonable placement of the fossil taxon used in the dating analysis would give more recent divergence time estimates.

worldwide distribution of Ipomopsis

worldwide distribution of Ipomopsis

Taxonomy (* indicates South American taxa)

Ipomopsis is a taxonomically complex genus as evidenced by the large number of subspecific entities below.  Much of the nomenclatural complexity is likely a result of multiple factors including elevational ecotypes and hybrid swarms (Grant and Wilken 1987, 1988). The I. aggregata complex has been treated by Grant and Wilken (1986), the I. congesta complex by Constance and Rollins (1936) and the I. spicata complex by Wilken and Hartman (1991).  A robust hypothesis of the phylogentic relationships is needed to help rectify these taxonomic issues.

  1. Ipomopsis aggregata (Pursh) V.E. Grant
    • I. aggregata (Pursh) V.E. Grant subsp. aggregata
    • I. aggregata (Pursh) V.E. Grant subsp. attenuata (A.Gray) V.E. Grant & A.D. Grant
    • I. aggregata (Pursh) V.E. Grant subsp. bridgesii (A. Gray) V.E. Grant & A.D. Grant
    • I. aggregata (Pursh) V.E. Grant subsp. candida (Rydb.) V.E. Grant & A.D. Grant
    • I. aggregata (Pursh) V.E. Grant subsp. carmenensis Henr.
    • I. aggregata (Pursh) V.E. Grant subsp. collina (Greene) Wilken & Allard
    • I. aggregata (Pursh) V.E. Grant subsp. formosissima (Greene) Wherry
    • I. aggregata (Pursh) V.E. Grant subsp. texana (Greene) Wherry
    • I. aggregata (Pursh) V.E. Grant subsp. weberi V.E. Grant & Wilken
  2. Ipomopsis arizonica (Greene) Wherry
  3. Ipomopsis congesta (Hook.) V.E. Grant
    • I. congesta (Hook.) V.E. Grant subsp. congesta
    • I. congesta (Hook.) V.E. Grant subsp. crebrifolia (Nutt.) A.G. Day
    • I. congesta (Hook.) V.E. Grant subsp. frutescens (Rydb.) A.G. Day
    • I. congesta (Hook.) V.E. Grant subsp. mathewsii J.M. Porter
    • I. congesta (Hook.) V.E. Grant subsp. montana (A. Nels. & P.B. Kenn.) V.E. Grant
    • I. congesta (Hook.) V.E. Grant subsp. nevadensis (Tidestr.) Karst. & Gandhi
    • I. congesta (Hook.) V.E. Grant subsp. palmifrons (Brand) A.G. Day
    • I. congesta (Hook.) V.E. Grant subsp. viridis (Cronq.) A.G. Day
  4. Ipomopsis effusa (A. Gray) Moran
  5. Ipomopsis gossypifera (Gillies) V.E. Grant*
  6. Ipomopsis gunnisonii (Torr. & A. Gray) V.E. Grant
  7. Ipomopsis guttata (A. Gray) Moran
  8. Ipomopsis havardi (A. Gray) V.E. Grant
  9. Ipomopsis laxiflora (J.M. Coult.) V.E. Grant
  10. Ipomopsis longiflora (Torr.) V.E. Grant
    • I. longiflora (Torr.) V.E. Grant subsp. australis R.A. Fletcher & W.L. Wagner
    • I. longiflora (Torr.) V.E. Grant subsp. longiflora 
    • I. longiflora (Torr.) V.E. Grant subsp. neomexicana Wilken
  11. Ipomopsis macombii (Torr.) V.E. Grant
  12. Ipomopsis macrosiphon (Kearney & Peebles) V.E. Grant & Wilken
  13. Ipomopsis monticola J.M. Porter & L.A. Johnson
  14. Ipomopsis multiflora (Nutt.) V.E. Grant
  15. Ipomopsis pinnata (Cav.) V.E. Grant
  16. Ipomopsis polyantha (Rydb.) V.E. Grant
    • I. polyantha (Rydb.) V.E. Grant subsp. polyantha
    • Gilia (I.) polyantha Rydb. var. whitingii Kearney & Peebles
  17. Ipomopsis polycladon (Torr.) V.E. Grant
  18. Ipomopsis pringlei (A. Gray) Henr.
  19. Ipomopsis pumila (Nutt.) V.E. Grant
  20. Ipomopsis ramosa A.L. Schneid. & Bregar
  21. Ipomopsis roseata (Rydb.) V.E. Grant
  22. Ipomopsis rubra (L.) Wherry
  23. Ipomopsis sancti-spiritus Wilken & R.A. Fletcher
  24. Ipomopsis sonorae (Rose) A.D. Grant
  25. Ipomopsis spicata (Nutt.) V.E. Grant
    • I. spicata (Nutt.) V.E. Grant subsp. capitata (A. Gray) V.E. Grant
    • I. spicata (Nutt.) V.E. Grant subsp. orchidacea (Brand) Wilken & R.L. Hartm.
    • I. spicata (Nutt.) V.E. Grant subsp. robruthiae Wilken & R.L. Hartm.
    • I. spicata (Nutt.) V.E. Grant subsp. tridactyla Wilken & R.L. Hartm.
  26. Ipomopsis tenuifolia (A. Gray) V.E. Grant
  27. Ipomopsis tenuituba  (Rydb.) V.E. Grant
    • I. tenuituba (Rydb.) V.E. Grant subsp. latiloba V.E. Grant & Wilken
    • I. tenuituba (Rydb.) V.E. Grant subsp. tenuituba
  28. Ipomopsis thurberi (Torr.) V.E. Grant
  29. Ipomopsis wendtii Henr.
  30. Ipomopsis wrightii (A. Gray) Shinners

References

Constance, L. and R. C. Rollins. 1936. A Revision of Gilia congesta and Its Allies. American Journal of Botany  23: 433-440.

Grant, V. and D. Wilken. 1988. Natural hybridization between Ipomopsis aggregata and I. tenuituba (Polemoniaceae). Botanical Gazette 149: 213-221.

Grant, V. and D. Wilken. 1987. Secondary intergradation between Ipomopsis aggregata ssp.candida and I. a. collina (Polemoniaceae). Botanical Gazette 148: 372-378.

Grant, V. and D. Wilken. 1986. Taxonomy of the Ipomopsis aggregata group (Polemoniaceae). Botanical Gazette 147: 359-371.

Porter, J.M., L.A. Johnson, and  D. Wilken.  2010.  Phylogenetic Systematics of Ipomopsis (Polemoniaceae): Relationships and Divergence Times Estimated from Chloroplast and Nuclear DNA Sequences.  Systematic Botany  35: 181-200

Wilken, D. and R. Hartman. 1991. A revision of the Ipomopsis spicata complex (Polemoniaceae). Systematic Botany 16: 143-161.

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