Leavenworthia

Classification System: APG IV

Superregnum: Eukaryota
Cladus: Orthokaryota
Cladus: Neokaryota
Cladus: Photokaryota
Cladus: Diaphoretickes
Cladus: CAM
Regnum*: Archaeplastida
Regnum: Plantae
Regnum*: Viridiplantae
Cladus: Streptophyta
Cladus: Phragmoplastophyta
Cladus: Embryophyta
Cladus: Polysporangiophyta
Divisio*: Tracheophyta
Cladus: Eutracheophyta
Cladus: Euphyllophytina
Cladus: Megaphylla
Cladus: Radiatopses
Cladus: Lignophyta
Cladus: Metalignophyta
Diviso*: Spermatophyta
Classis*: Angiospermae
Cladus: Mesangiospermae
Cladus: Eudicota
Cladus: Core eudicots
Cladus: Rosids
Cladus: Eurosids II
Ordo: Brassicales

Familia: Brassicaceae
Subfamilia: Brassicoideae
Tribus: Cardamineae
Genus: Leavenworthia
Species: L. alabamica – L. aurea – L. crassa – L. exigua – L. stylosa – L. texana – L. torulosa – L. uniflora
Name

Leavenworthia Torr. Ann. Lyceum Nat. Hist. New York 4(1): 87–94, pl. 5. (1837)

Type species: Leavenworthia aurea Torr. Ann. Lyceum Nat. Hist. New York 4(1): 88–89, pl. 5, f. 1–8 (1837)

References

Torrey, J. 1837. Annals of the Lyceum of Natural History of New York 4(1): 87–94, pl. 5.
International Plant Names Index. 2016. Leavenworthia. Published online. Accessed: Dec. 23 2016. Reference page.
Koch, M.A. et al. 2016. Leavenworthia in BrassiBase Tools and biological resources to study characters and traits in the Brassicaceae. Published online. Accessed: 2016 Dec. 23.
Warwick, S.I., Francis, A. & Al-Shehbaz, I.A. 2006. Brassicaceae: species checklist and database on CD-Rom. Plant Systematics and Evolution 259(2–4): 249–258. DOI: 10.1007/s00606-006-0422-0 ResearchGate Reference page.

Leavenworthia is a genus of flowering plants in the family Brassicaceae. It includes about eight species native to the southern and southeastern United States.[1] They are known generally as gladecresses.[2][3]
Description
Leavenworthia exigua from Central Tennessee showing characteristic siliques.

These are small annual herbs under 10 centimeters tall.[4] They produce a basal rosette of leaves and often lack a true stem, instead sending up a scape, a flowering stalk topped with an inflorescence. The inflorescence is usually made up of just one flower, but a large plant may produce several flowers in a raceme. The petals are white, yellow, orange, or lavender. They are often notched and clawed, narrow at the base and wider at the tip. There are six stamens, two short and four long. The fruits are siliques or silicles of various shapes. The seeds are flattened and have wide margins or wings.[1]
Ecology

Leavenworthia species are mainly restricted to habitats with limestone substrates, especially cedar glades.[5] These glades can be very wet in winter and spring, even flooded.[4] Several species are narrow endemics in terms of geography; L. alabamica and L. crassa are endemic to Alabama, L. aurea to Oklahoma, L. stylosa to Tennessee, and L. texana to Texas.[1]
Breeding systems

The mating systems found in genus Leavenworthia have been studied extensively because they are variable and have changed several times in the evolutionary history of the group. Some species are self-compatible, while others are self-incompatible. L. exigua, L. torulosa, and L. uniflora are self-compatible, able to produce seed from ovules fertilized by their own pollen. In L. alabamica and L. crassa, separate populations of self-compatible and self-incompatible individuals have been observed. At at least three points in the history of Leavenworthia there have been transitions between mating systems, in which self-incompatible plants evolved self-compatibility, developing the ability to fertilize their own ovules.[4]

This process has inspired studies of the genetics of the genus, which may help explain how such changes occurred. Self-incompatibility is the ancestral state of the genus, and it has been lost several times.[6] The transition from self-incompatibility to self-compatibility is described as the loss of a barrier, rather than the gain of a new function; in L. alabamica, for example, a mutation in a pollen gene may have led to the production of compatible pollen.[7] Self-compatible plants are also shaped differently, with smaller flowers in which the pollen-bearing anthers are positioned closer to the stigma.[6]
Diversity

Taxa include:[1][2][3][8]

Leavenworthia alabamica – Alabama gladecress
Leavenworthia alabamica var. alabamica
Leavenworthia alabamica var. brachystyla
Leavenworthia aurea – golden gladecress, golden yelloweye
Leavenworthia crassa – fleshyfruit gladecress
Leavenworthia crassa var. crassa
Leavenworthia crassa var. elongata
Leavenworthia exigua – Tennessee gladecress
Leavenworthia exigua var. exigua
Leavenworthia exigua var. laciniata – Kentucky gladecress
Leavenworthia exigua var. lutea
Leavenworthia stylosa – cedar gladecress
Leavenworthia texana (syn. L. aurea var. texana) – Texas golden gladecress
Leavenworthia torulosa – necklace gladecress
Leavenworthia uniflora – Michaux's gladecress

References

Leavenworthia. Flora of North America.
Leavenworthia. USDA PLANTS.
Leavenworthia. Integrated Taxonomic Information System (ITIS).
Beck, J. B., et al. (2006). Leavenworthia (Brassicaceae) revisited: testing classic systematic and mating system hypotheses. Systematic Botany 31(1), 151-59.
Baskin, J. M. and C. C. Baskin. (1978). The rarity of Leavenworthia uniflora, with special reference to its occurrence in Kentucky. Castanea 43(1) 54-57.
Busch, J. W. (2005). The evolution of self-compatibility in geographically peripheral populations of Leavenworthia alabamica (Brassicaceae). American Journal of Botany 92(9), 1503-12.
Chantha, S. C., et al. (2013). Secondary evolution of a self-incompatibility locus in the Brassicaceae genus Leavenworthia. PLoS Biology 11(5), e1001560.

GRIN Species Records of Leavenworthia. USDA Germplasm Resources Information Network (GRIN).