Houstonia (genus)
Houstonia (Bluet) is a genus of plants in the Rubiaceae family. Many species were formerly placed (along with other now-segregate genera) in a more inclusive Hedyotis.
Bluets are often small and delicate. For example, H. rosea may attain a height of only one inch. Some species have a single-stem, while others are more "bunchy." Flowers may be blue, purple, lavender, white, or rose, often with shades of one color present in a single population. Flowers have four sepals, a salverform corolla with four lobes, and an inferior ovary. Some species exhibit heterostyly. The fruit is many-seeded capsule which usually dehisces via a suture across the apex; often the capsule is roughly heart-shaped.
Houstonia consists of 20 species native to North America.[1] Another five species are classified in the genus Stenaria (Houstonia without Stenaria is paraphyletic).[2] Close relatives of the genus are Oldenlandia and Hedyotis.[1]
Species
- Houstonia acerosa
- Houstonia angustifolia
- Houstonia caerulea Azure bluet
- Houstonia calycosa
- Houstonia canadensis Canadian summer bluet
- Houstonia ciliolata
- Houstonia setiscaphia
- Houstonia correllii Correll's bluet
- Houstonia croftiae Croft's bluet
- Houstonia filifolia
- Houstonia floridana
- Houstonia humifusa Matted bluet
- Houstonia lanceolata
- Houstonia longifolia Longleaf summer bluet
- Houstonia micrantha Southern bluet
- Houstonia minima
- Houstonia montana
- Houstonia mullerae
- Houstonia nigricans Diamondflowers
- Houstonia ouachitana Ouachita bluet
- Houstonia parviflora Greenman's bluet
- Houstonia patens
- Houstonia polypremoides
- Houstonia procumbens Roundleaf bluet
- Houstonia pulvinata
- Houstonia purpurea Venus' pride
- Houstonia pusilla Tiny bluet
- Houstonia pygmaea
- Houstonia rigidiuscula
- Houstonia rosea Rose bluet
- Houstonia rotundifolia
- Houstonia rubra Red bluet
- Houstonia salina
- Houstonia serpyllifolia Thymeleaf bluet
- Houstonia subviscosa Nodding bluet
- Houstonia tenuifolia
- Houstonia tenuis
- Houstonia wrightii Pygmy bluet
References
- ^ a b Edward E. Terrell (Jun. 10, 1996), "Revision of Houstonia (Rubiaceae-Hedyotideae)", Systematic Botany Monographs (American Society of Plant Taxonomists) 48: 1–118, doi:10.2307/25027862, JSTOR 25027862
- ^ Sheri A. Church and Douglas R. Taylor (2005), "Speciation and hybridization among Houstonia (Rubiaceae) species: the influence of polyploidy on reticulate evolution", American Journal of Botany 92 (8): 1372–1380, doi:10.3732/ajb.92.8.1372