Allophyllum

Allophyllum is a small genus of six species of glandular-pubescent annuals endemic to southwestern North America.

Biogeography

Allophyllum is endemic to the western United States and Baja California.  It is most diverse in California with five of the six species in the genus found in that state.  Allophyllum giliodies shows a disjunct distribution on either side of the Mojave Desert.

AllophyllumPhylogeny

Molecular data places Allophyllum as the sister genus to a clade comprised of Collomia and Navarretia, in line with the proposed hypothesis of Grant and Grant (1955) based on a large amount of morphological similarity to Collomia.

Within Allophyllum, Grant and Grant (1955) recognize two “series.” One series is comprised of small plants similar to A. gilioides with linear leaf segments, sparsely pubescent stems, and slightly irregular flowers.  By contrast, the second series is comprised of of more robust plants similar to A. divaricatum with broad leaf segments, villous stems, and more or less regular flowers.  However, molecular sequence data indicates that these series are not monophyletic.  Given that the species have a propensity to interbreed (at least in controlled crosses) and occur in sympatry (Grant and Grant 1955) more molecular data is needed to confirm these results.

Taxonomy

  1. Allophyllum divaricatum (Nutt.) A.D. Grant and V.E. Grant
  2. Allophyllum gilioides (Benth.) A.D. Grant and V.E. Grant
  3. Allophyllum glutinosum (Benth.) A.D. Grant and V.E. Grant
  4. Allophyllum integrifolium (Brand) A.D. Grant and V.E. Grant
  5. Allophyllum nemophilophyllum J.M. Porter and L.A. Johnson
  6. Allophyllum violaceum (A. Heller) A.D. Grant and V.E. Grant

KEY TO ALLOPHYLLUM (modified from Grant and Grant 1955)

1. Cauline leaf segments 3-15 mm wide; corolla 6-22 mm long; stamens exserted or included; herbage distinctly glandular
2. Stamens equal in length; lower leaves entire to pinnately lobed; capsules 3 seeded
3. Corolla tube 6-16 mm; inflorescence 4-8 flowered…A. divaricatum
3′. Corolla tube 5-8 mm; inflorescence 2 flowered…A. integrifolium
2′. Stamens unequal in length; lower leaves pinnate to bi-pinnately lobed; capsules 6-9 seeded…A. glutinosum
1′. Segments of cauline leaves < 3 mm wide; corolla 2-9.5 mm; stamens included; herbage not distinctly glandular
4. Flower pedicels elongate (6)-11-33 mm…A. nemophilophyllum
4′. Flower pedicels << 11 mm
5. Inflorescence head-like, 4-8 flowered; plant with many pinnately lobed leaves; inflorescence branches arising above the middle of the plant…A. gilioides
5′. Inflorescence loose, 2-3 flowered; plant with few pinnately lobed leaves; inflorescence branches arising throughout the plant…A. violaceum

References

Grant, A., and V. Grant. 1955. The genus Allophyllum (Polemoniaceae). Aliso 3: 93–110.

Porter, J. M. and L. A. Johnson. 2000. A phylogenetic classification of Polemoniaceae. Aliso 19: 55-91.

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