Hexastylis
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Hexastylis is a genus in the family of aristolochiaceae (Aristolochiaceae). The ten or so species are common in North America .
description
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Vegetative characteristics
Hexastylis species are evergreen , perennial, herbaceous plants . They have rhizomes , but no above-ground shoot axes . The leaves are alternate. Stipules are missing. Both stalked leaves and sessile scale leaves are present. The simple leaf blades are glabrous and membranous or leathery.
Generative characteristics
The inflorescences arise terminally from the rhizomes. The flowers are single and opposite each of them is a triangular bract . The flowers are hermaphroditic. The sepals are fused together over most of their length. Their color is usually a mix of brown, purple, or yellow. Outside and inside are hairless. The sepals have a weak to strong network of ridges. The calyx tube never forms a delimited fruit tube . There are no petals , not even rudimentary ones. The 12 stamens are not grown. The stamens are shorter than the pollen sacs. Terminal appendages of the anthers are missing or only rudimentary. The ovary is six-chambered and superordinate or partly in the middle. The six styles are not overgrown, but they can rarely grow together at the base.
The fleshy capsule fruit opens irregularly. The seeds are egg-shaped, not winged and have fleshy appendages.
The basic chromosome number is x = 13.
Systematics and distribution
Hexastylis was first described by Constantine S. Rafinesque-Schmaltz in 1825 .
The genus Hexastylis occurs in North America . It includes up to ten species (however, some authors put many of the species in Asarum ):
- Hexastylis arifolia (Michx.) Small : There are three varieties. It occurs in the US states of Alabama, Florida, North Carolina, South Carolina, Louisiana, Georgia, Tennessee, Virginia and Mississippi at altitudes from 0 to 800 meters.
- Hexastylis contracta H.L.Blomq. : It thrives in deciduous forests with Kalmia and rhododendrons at altitudes of 300 to 1000 meters in the US states in Kentucky, Tennessee and North Carolina.
- Hexastylis heterophylla (Ashe) Small : It is found in West Virginia, Alabama, Virginia, Kentucky, North Carolina, South Carolina, Tennessee, and Georgia.
- Hexastylis lewisii (Fernald) HLBlomq. & Oosting : It occurs in North Carolina and Virginia.
- Hexastylis minor (Ashe) HLBlomq. : It occurs in North Carolina, South Carolina, and Virginia.
- Hexastylis naniflora H.L.Blomq. : It occurs in North Carolina and South Carolina often together with Kalmia latifolia at altitudes of 500 to 700 meters.
- Hexastylis rhombiformis Gaddy : It occurs in North Carolina and South Carolina often together with Kalmia latifolia and Rhododendron maximum at altitudes of 500 to 1000 meters.
- Hexastylis shuttleworthii (Britten & Baker f.) Small : It occurs in Alabama, Georgia, North Carolina, South Carolina, Tennessee, Mississippi, and Virginia. There are two varieties.
- Hexastylis speciosa R.M. Harper : This endemic occurs only north of Montgomery in Alabama .
- Hexastylis virginica (L.) Small : It occurs in the US states of Kentucky, Maryland, North Carolina, Tennessee, Virginia and West Virginia at altitudes of 0 to 700 meters.
literature
- Alan T. Whittemore, LL Gaddy: Hexastylis. - Same text online as the printed work , In: Flora of North America Editorial Committee (Ed.): Flora of North America North of Mexico. Volume 3: Magnoliophyta: Magnoliidae and Hamamelidae. Oxford University Press, New York and Oxford, 1997, ISBN 0-19-511246-6 .
Individual evidence
- ↑ a b c d Hexastylis in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland. Retrieved June 3, 2018.
