Grayia
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Grayia is a genus of plants from the subfamily Chenopodioideae in the foxtail family(Amaranthaceae). The four shrubby species occur in arid regions in the western United States and are known there under the common names "siltbush" and "hopsage".
description
Appearance and leaves
The Grayia species are semi-shrubs or shrubs and reach heights of 15 to 150 centimeters. The woody shoot axes grow upright or ascending and are heavily branched. The bark of old twigs is gray-brown. Young twigs are ribbed or striped and densely hairy, but later bald. The side branches can end in thorny tips. In the leaf axils there are clearly protruding, almost spherical buds.
The alternate leaves are sessile or slightly narrowed at the base of the leaf. The green or gray, fleshy or leathery leaf blades are elliptical, egg-shaped, obovate, spatulate or linear-lanceolate with a length of 6 to 80 millimeters and a width of 1.5 to 42 millimeters. The leaves have a protruding central rib and a smooth leaf margin. Especially in the area of the leaf tip, the leaves are often hairy with simple or branched trichomes . The leaf anatomy corresponds to the "normal" (non-wreath) type of C3 plants .
Inflorescences and flowers
The Grayia species are dioecious ( dioecious ) or monoecious ( monoecious ) separate sexes. In axillary or terminal, pseudo-eared or paniculate , interrupted inflorescences , the male flowers are clustered together or the female flowers are single. The male flowers (without bracts) have an inflorescence of four to five membranous tepals from 1 to 1.8 millimeters in length with a hood-like tip connected to the middle . In front of the tepals there are four to five stamens that arise from a discus. The anthers do not protrude from the flower. The female flowers sit between two bracteoles , they have no flower cover and only consist of an ovary with two thread-like, protruding stigmas.
The grayia species bloom in their natural range from March to June.
Fruits and seeds
At the time of fruiting, the enveloping pre-leaves grow to 4 to 15 millimeters in length and width. They are folded along the midrib and connected almost to the tip, which is characteristic of the genus Grayia . Their shape is round, broadly elliptical or heart-shaped, usually with entire margins, sometimes also wavy or enlarged to two wings. Their surface can be flat or ribbed, bald or hairy. The initially yellowish-green or cream-colored bracte oils turn reddish or pink as they ripen. The ripe fruit, which remains enclosed by the bracts, does not fall off. It is spherical, obovate or lenticularly compressed at the side, its membranous pericarp is free or only loosely adheres to the seed. The vertically or horizontally standing seed has a brown or yellowish-brown, thin and membranous seed coat. The ring-shaped embryo surrounds the abundant, floury nutrient tissue .
Sets of chromosomes
The chromosome numbers given are 2n = 18 for the diploid Grayia arizonica and Grayia brandegeei and 2n = 36 for the tetraploid Grayia spinosa and Grayia plummeri .
Occurrence
The genus Grayia is native to the western United States (in Arizona , California , Colorado , Idaho , Montana , New Mexico , Nevada , Oregon , Utah , Washington, and Wyoming ). It occurs in arid and semi-arid regions and grows on heavy to sandy loam, on alkaline or barely salty soil. The distribution areas of the individual species overlap, but the species each colonize different habitats.
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Systematics
The first description of the genus Grayia was made in 1840 by William Jackson Hooker and George Arnott Walker Arnott (in: The Botany of Captain Beechey's Voyage , p 387-388). The genus name honors the American botanist Asa Gray . The genus then comprised only one species, Grayia polygaloides Hook. & Arn. (nom. illeg.) based on Chenopodium spinosum Hook. and by Alfred Moquin-Tandon in 1849 the valid name Grayia spinosa (Hook.) Moq. received.
Grayia belongs to the tribe Atripliceae of the subfamily Chenopodioideae in the family Amaranthaceae . Until 2010, the genus was considered monotypical . After phylogenetic studies, Zacharias & Baldwin (2010) also subdivided the genus Zuckia Standl. here one.
The genus Grayia thus includes four species:
- Grayia arizonica (Standl.) EHZacharias (Syn. Zuckia arizonica Standl. , Zuckia brandegeei var. Arizonica (Standl.) SLWelsh ): This species occurs in Arizona and Utah and is called "Arizona siltbush".
- Grayia brandegeei A.Gray (Syn. Zuckia brandegeei (A.Gray) SLWelsh & Stutz ): This species occurs in Colorado, Arizona and Utah and is called "Brandegee's siltbush".
- Grayia plummeri (Stutz & SCSand.) EHZacharias (Syn. Grayia brandegeei var. Plummeri Stutz & SC Sand. , Zuckia brandegeei var. Plummeri (Stutz & SCSand.) Dorn ): It occurs in Colorado, Wyoming, New Mexico and Utah and is known as "Plummer's siltbush".
- Grayia spinosa (Hook.) Moq. : It is widespread in Colorado, Idaho, Montana, Oregon, Washington, Wyoming, Arizona, California, Nevada, and Utah; their common name is "spiny hopsage".
swell
- Elizabeth H. Zacharias, Bruce G. Baldwin: A Molecular Phylogeny of North American Atripliceae (Chenopodiaceae), with Implications for Floral and Photosynthetic Pathway Evolution . In: Systematic Botany , Volume 35 (4), 2010, pp. 839-857. doi : 10.1600 / 036364410X539907 (sections description, occurrence, systematics)
Individual evidence
- ^ Grayia in the Germplasm Resources Information Network (GRIN), USDA , ARS , National Genetic Resources Program. National Germplasm Resources Laboratory, Beltsville, Maryland. Retrieved July 17, 2013.
- ^ Grayia - first description, scanned at BHL
- ↑ a b Noel H. Holmgren: Grayia - text same online as printed work , In: Flora of North America Editorial Committee (Ed.): Flora of North America North of Mexico . Volume 4: Magnoliophyta: Caryophyllidae, part 1 . Oxford University Press, New York / Oxford a. a. 2003, ISBN 0-19-517389-9 , pp. 306 (English).
- ↑ Stanley L. Welsh: Zuckia - online text same as printed work , In: Flora of North America Editorial Committee (ed.): Flora of North America North of Mexico . Volume 4: Magnoliophyta: Caryophyllidae, part 1 . Oxford University Press, New York / Oxford a. a. 2003, ISBN 0-19-517389-9 , pp. 303 (English).
