Cantua

Cantua_buxifolia_plate

Cantua is a poorly known genus of at least 14 species native to montane tropical South America.

Phylogeny

Monfils and Prather (2010) examined the phylogenetic relationships of species of Cantua using a limited set of markers that generally provide limited infra-generic resolution in Polemoniaceae.  Nevertheless, their limited data suggest the potential for chloroplast capture by C. buxifolia from an ancestor of C. candelilla.

Taxonomy

  1. Cantua alutacea Infantes
  2. Cantua bicolor Lem.
  3. Cantua buxifolia Juss.
  4. Cantual candelilla Brand
  5. Cantua cuzcoensis Infantes
  6. Cantua dendritica J.M. Porter & Prather
  7. Cantua flexuosa (Ruiz & Pav.) Pers.
  8. Cantua longifolia Brand
  9. Cantua mediamnis J.M. Porter & Prather (replaced Huthia longiflora Brand)
  10. Cantua ovata Cav.
  11. Cantua pyrifolia Juss.
  12. Cantua quercifolia Juss.
  13. Cantua tomentosa Cav.
  14. Cantua volcanica J.M. Porter & Prather (replaced Huthia caerulea Brand)

Biogeography

Cantua is restricted to high elevations in the mountains of Bolivia, Ecuador, and Peru

CantuaKEY TO CANTUA (modified from Infantes, 1962)
Note: C. mediamnis is only known from a single collection. It is morphologically similar to C. volcanica and would key out to that species

1. Leaves conspicuously and regularly dentate
2. Flowers white; leaves broad…C. quercifolia
2′. Flowers blue; leaves linear…C. volcanica
1′. Leaves entire, finely serrate, or rarely inconsistently dentate
3. Margins of corolla lobes pilose
4. Corolla tube pubescent…C. pyrifolia
4′. Corolla tube glabrous
5. Mature leaves entire
6. Corolla lobes mucronate…C. ovata
6′. Corolla lobes not mucronate…C. cuzocensis
5′. Mature leaves toothed in the upper part
12. Calyx 11-12 mm, glandular-pilose…C. dendritica
12′. Calyx 6.5-10.5 mm, pubescence simple…C. flexuosa
3′. Margins of corolla lobes glabrous
7. Mature leaves toothed above the middle…C. longifolia
7′. Mature leaves entire, or if tooted inconsistently so
8. Corolla tube glabrous throughout
9. Flowers large, 5-8 cm long
10. Anthers small, 2.6 mm long, flowers red…C. buxifolia
10′. Anthers large, 3-9 mm long, flowers yellow…C. alutacea
9′. Flowers smaller, 3-5 cm long…C. bicolor
8′. Corolla tube pubescent in the upper part
11. Corolla pubescence tomentose; of glandular hairs…C. tomentosa
11′. Corolla pubescence not tomentose; of simple hairs…C. candelilla

References

Infantes Vera, J. G. 1962. Revision del genero Cantua (Polemoniaceae). Lilloa 31: 75– 107.

Monfils, A. K. and L. A. Prather. 2004. The conserved nature and taxonomic utility of pollen morphology in Cantua (Polemoniaceae). Grana 43:1-8.

Monfils, A. K. and L. A. Prather. 2010.  Phylogeny of Cantua (Polemoniaceae subfamily Cobaeoideae): Evidence from chloroplast and nuclear DNA sequence data. Systematic Botany 35 (4):877-884.

Porter, J. M., and L. A. Prather. 2008. Cantua dendritica (Polemoniaceae) a new species from Peru, and two new Cantua names. Aliso 24: 31–35.

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