''Echinocereus viridiflorus'' is a species of

cactus A cactus (, or less commonly, cactus) is a member of the plant family Cactaceae, a family comprising about 127 genera with some 1750 known species of the order Caryophyllales. The word ''cactus'' derives, through Latin, from the Ancient Greek ...

known by the common names nylon hedgehog cactus, green pitaya, and small-flowered hedgehog cactus. It is native to the central and south-central

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

and northern

Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

, where it can be found in varied habitat types, including

desert scrub Deserts and xeric shrublands are a biome defined by the World Wide Fund for Nature. Deserts and xeric (ancient Greek xērós, “dry") shrublands form the largest terrestrial biome, covering 19% of Earth's land surface area. Ecoregions in this ...

woodland A woodland () is, in the broad sense, land covered with trees, or in a narrow sense, synonymous with wood (or in the U.S., the ''plurale tantum'' woods), a low-density forest forming open habitats with plenty of sunlight and limited shade (see ...

s, dry

grassland A grassland is an area where the vegetation is dominated by grasses (Poaceae). However, sedge (Cyperaceae) and rush (Juncaceae) can also be found along with variable proportions of legumes, like clover, and other herbs. Grasslands occur natur ...

s, and

short-grass prairie The shortgrass prairie is an ecosystem located in the Great Plains of North America. The two most dominant grasses in the shortgrass prairie are blue grama (''Bouteloua gracilis'') and buffalograss (''Bouteloua dactyloides''), the two less domina ...

.''Echinocereus viridiflorus''.
Flora of North America.

Description

This cactus has a small spherical to ovoid, sometimes elongated or cylindrical in shape, stem to over tall and up to wide. The 6 to 18 ribs are clearly humps. It is mostly unbranched but it may occur in squat clusters of several branches. The body of the plant is ridged and lined with many areoles bearing spines. The spines may be red, yellow, white, purplish, or bicolored, sometimes with darker tips and are up to long. The 8 to 24 marginal spines are also red, cream or brown and up to long. The flower is up to long and has

tepal A tepal is one of the outer parts of a flower (collectively the perianth). The term is used when these parts cannot easily be classified as either sepals or petals. This may be because the parts of the perianth are undifferentiated (i.e. of very ...

s in shades of yellowish, brownish, greenish, or occasionally red, with darker reddish midstripes. The tepals are thin at the tips. They are usually wide open, funnel-shaped and green to yellow-green. They are long and large in diameter. The fruits are spherical, green and heavily thorny. File:Echinocereus virdiflorus.JPG, ''Echinocereus viridiflorus'' File:Echinocereus viridiflorus 1211035.jpg

Taxonomy

The species is most closely related to ''E. chloranthus'' (Engelm.) Haage and ''E. russanthus'' Weniger.Sánchez, D., Arias, S., & Terrazas, T. (2014). Phylogenetic relationships in Echinocereus (Cactaceae, Cactoideae). ''Systematic Botany, 39''(4), 1183-1196. These species share small seeds, basal nectaral tissue, and flowers that are yellow/brown and less than 4 cm in length. The

taxonomy Taxonomy is the practice and science of categorization or classification. A taxonomy (or taxonomical classification) is a scheme of classification, especially a hierarchical classification, in which things are organized into groups or types. ...

within the species is uncertain, with authors recognizing several varieties which are sometimes treated as separate species. New molecular evidence suggests that ''E. viridiflorus'' subsp. ''cylindricus'' should be recognized as a distinct species because it has different morphology and different numbers of molecular autapomorphies than ''E. viridiflorus''. One variety, var. ''davisii'' (sometimes called ''Echinocereus davisii''), Davis' green pitaya, is federally listed as an

endangered species An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and inv ...

. This taxon is very small, reaching no more than 3 centimeters tall. It becomes smaller when water is scarce, withdrawing under the ground, sometimes leaving just some spines sticking out.''Echinocereus davisii''.
Flora of North Americavar. ''davisii''.
Center for Plant Conservation.

Subspecies

Distribution

''Echinocereus viridiflorus'' is widespread in the US states of South Dakota, Wyoming, Colorado, Kansas, New Mexico, Oklahoma and Texas, as well as in the neighboring Mexican states of Coahuila and Chihuahua. It has yellow-green flowers. This rare variety is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

to Brewster County, Texas, where it grows in beds of ''

Selaginella ''Selaginella'' is the sole genus of vascular plants in the family Selaginellaceae, the spikemosses or lesser clubmosses. This family is distinguished from Lycopodiaceae (the clubmosses) by having scale-leaves bearing a ligule and by having ...

'' in rocky soils of

novaculite Novaculite, also called Arkansas Stone, is a microcrystalline to cryptocrystalline rock type that consists of silica in the form of chert or flint. It is commonly white to grey or black in color, with a specific gravity that ranges from 2.2 to 2.5 ...

origin.USFWS
var. ''davisii'' Recovery Plan.
September 1984. There was only one population known as of 1984, and it probably will not expand its range because it is limited to a specific mineral substrate.

References

External links

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USDA Plants Profile — ''Echinocereus viridiflorus''''Echinocereus viridiflorus'' Photo gallery
{{Taxonbar, from=Q150223 viridiflorus Cacti of Mexico Cacti of the United States Flora of the Great Plains (North America) Flora of the Chihuahuan Desert Flora of the Rio Grande valleys Flora of Colorado Flora of New Mexico Flora of Texas Flora of Wyoming