| Pelecyphora sneedii | |
|---|---|
 | |
Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Tracheophytes |
| Clade: | Angiosperms |
| Clade: | Eudicots |
| Order: | Caryophyllales |
| Family: | Cactaceae |
| Subfamily: | Cactoideae |
| Genus: | Pelecyphora |
| Species: | P. sneedii |
| Binomial name | |
| Pelecyphora sneedii | |
| Synonyms[2] | |
| |
Pelecyphora sneedii (syn.Coryphantha sneedii) is a rare species ofcactus known by the common namesSneed's pincushion cactus andcarpet foxtail cactus. It is endemic to theChihuahuan Desert of thesouthwestern United States and northwesternMexico. It is a small, variable cactus with a lengthy taxonomic history, and is often subdivided into a number of subspecies or varieties. It is usually found on steep, rocky habitats, primarily oflimestone geology, in desert scrub or coniferous forest. A species of conservation concern,P. sneedii faces threats frompoaching,urban encroachment, andwildfires.
The former cacti speciesCoryphantha orcuttii has been lumped intosneedii as a subspecies.P. sneedii alsointergrades withPelecyphora vivipara, further complicating classification. Because of the variation and intergradation ofP. sneedii, it forms aspecies complex.
Pelecyphora sneedii is a small cactus growing up to about 27 centimetres (11 in) tall, but sometimes revealing just a few centimeters above ground level, the rest of the stem buried. The species may branch profusely, even when small and immature, forming up to 250 branches in some populations. It is coated densely inareoles of bright white spines; each areole may have nearly 100 spines. There are 25 to 52 radial spines per areole that are more or less appressed or tightly appressed, measuring 3–14 mm (0.12–0.55 in) long. There are 8 to 17 outer central spines per areole, which may be appressed to strongly projecting. There are up to 5 inner central spines per areole, which are typically straight and radiate like spokes, measuring 3–25 mm (0.12–0.98 in) long. Depending on the substrate, the spines may be tinted with yellow, pink, purple, or brown. They may have dark tips and as the cactus ages the spines darken to gray and even black.[3]
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P. sneedii typically blooms in spring from March to June, bearing flowers 1–3 cm (0.39–1.18 in) long and 7–25 mm (0.28–0.98 in) wide near the apical part of the stem. The outertepals are sparsely to densely fringed at the margins. There are 11 to 26 inner tepals, and vary in color from white, cream, pale tan, greenish white, or pale rose-pink. There are usually well-defined midstripes of various colors (usually darker) on the tepals, or they can sometimes be absent. The inner tepals measure 5–14 mm (0.20–0.55 in) long by 0.8–4 mm (0.031–0.157 in) wide. Thestamens have low-contrast filaments (often the same color as the tepals) with sulphur yellow or canary yellow anthers atop. The stigma is divided into 2 to 7 pale lobes, 1–3 mm (0.039–0.118 in) long.[3]
The fruits, which emerge from May to September, are dimorphic, with "red" (blood-red to magenta) and "green" (greenish-yellow to brown or purple) color phases. The fruits have a cylindric to fusiform or obovoid to narrowly clavate shape, and are up to 21 millimetres (0.83 in) long. The dried remains of the flower remain persistent on the fruit, and the fruit quickly dries out of its originally juicy and succulent form. The seeds are a brownish color, and are 1.6 millimetres (0.063 in) long, with a distinctive pitting on their surface.[3]
Escobaria sneedii was first described by botanistsNathaniel Lord Britton andJoseph Nelson Rose in 1923, in the fourth volume of their monographThe Cactaceae. The species is named after J.R. Sneed, who collected thetype specimen in theFranklin Mountains of Texas. The specimen was then sent to Britton and Rose by S.L. Pattison in 1921.[4]
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Taxonomic circumscription of theMammillaria and its clade of related genera (the 'Mammilloid' clade)[note 1] has been complicated, and until recently was based largely onmorphological characters.Escobaria has been recognized as a subgroup ofCoryphantha sinceBenson (1969, 1982) andCoryphantha was originally circumscribed in 1856 byEngelmann as a subgenus ofMammillaria. Molecular phylogenetic studies starting in the 21st century suggested a number of these genera were not in factmonophyletic, and demanded re-circumscription.[5]
Coryphantha was suggested to be placed within the Mammilloid clade from a number of studies, but was also shown not to be monophyletic. In 2021, Breslin et. al. revised the Mammilloid clade based on the phylogenetic evidence up to that point, resulting in three genera,Mammillaria sensu stricto,Cochemeia sensu lato, andCoryphantha (includingEscobaria). However, the study by Breslin used a low number of samples for theCoryphantha, necessitating a 2022 study by Sánchez et. al. focused on theCoryphantha in particular. Monophyly ofCoryphantha was achieved by excludingEscobaria,Pelecyphora, andCoryphantha macromeris, which formed their own monophyletic group.[5]
Due to the priority of publication principle (Principle III) dictated by theInternational Code of Nomenclature for algae, fungi, and plants,Escobaria andC. macromeris are merged intoPelecyphora, as it was published first in 1843 byEhrenberg, preceding Britton and Rose'sEscobaria by 80 years. The restructuring of theCoryphantha, Pelecyphora andEscobaria results in the current combination for this species,Pelecyphora sneedii.[5]
As Gorelick (2015, 2021) notes in his articles on the plants,Coryphantha sneedii integrades withCoryphantha vivipara and both have a wide variety of taxa (both at species name or as infraspecies of both) in their continuum. The two also overlap in range. It is often very difficult to distinguish plants ofC. sneedii withC. vivipara, and even moreso with the varieties of each, although bothC. sneedii andC. vivipara are readily distinguishable from other plants placed in theCoryphantha by their druses, fruits, and pericarpels. Gorelick in 2021 suggested combining the entire species complex ofC. sneedii as a single variety ofC. vivipara.[6][note 2]
| Specific epithet | Taxonomic treatment | ||
|---|---|---|---|
| POWO & Sánchez et. al.[5][2] | Flora of North America[3] | Gorelick, 2021[6] | |
| orcuttii | Pelecyphorasneedii subsp.orcuttii | Coryphantha sneedii | Coryphantha vivipara var.sneedii |
| organensis | |||
| sandbergii | |||
| villardii | |||
| sneedii | Pelecyphorasneedii subsp.sneedii | ||
| albicolumnaria | |||
| leei | |||
| guadalupensis | |||
| vivipara | Pelecyphora vivipara | Coryphantha vivipara | Coryphantha vivipara |
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Recognition ofinfraspecific taxa withinPelecyphora sneedii varies across sources. The variability of this species makes infraspecific circumscription difficult. Some sources, like theFlora of North America, do not recognize any infraspecific taxa at all. The rank at which they are recognized also varies, with some placing the infraspecific taxa asvarieties and others assubspecies.[7] The variability ofPelecyphora sneedii poses a difficulty to the conservation of the species, as some of the infraspecific taxa designated as threatened (e.g. subsp.leei) are not universally recognized. TheUnited States Fish and Wildlife Service continues to recognize var.leei and var.sneedii and both arelisted as threatened taxa as of 2023.[8]
A cactus described in the 1980s,Escobaria sneedii var. guadalupensis, is sometimes included within this species.[3][9] But is a synonym of var.sneedii.[9]
Sánchez et. al. andPlants of the World Online recognize the two subspeciesPelecyphora sneedii subsp.orcuttii andPelecyphora sneedii subsp.sneedii.[2][5]
It is native to theChihuahuan Desert, where it occurs in scattered locations inNew Mexico,Texas, andChihuahua.[10] Some plants occurring inArizona may be included within this species.[3] It is usually found in broken, rocky terrain and steep slopes of Silurian-Ordovician-Cambrianlimestone, usually in Chihuahuan desert scrub and sometimes inconiferous woodlands in theTrans-Pecos region.[7][11][12]
This cactus, particularly var.sneedii was heavily collected for the cactus trade starting in the 1920s when it was discovered.[13] The var.leei also faced this threat.[14] There was no need for thispoaching, because the plant is easily propagated in the garden.[10] They have beenoverharvested from their natural habitat, the main reason why the two varieties, var.sneedii and var.leei, have been federally listed as endangered and threatened, respectively.[13][14] Most authors believe that var.leei is a New Mexicoendemic that only grows inCarlsbad Caverns National Park, and anyP. sneedii outside the park are var.sneedii.[15] Threats to the species outside the national park include habitat loss. One example is the loss of a population of var.sneedii that occurred when a road was built connectingLas Cruces, New Mexico, andEl Paso, Texas.[13]
Sneed's pincushion cactus is popular with cactus enthusiasts and dealers because of its often petite size and tolerance for moderately cold climates.[9]
In cultivation, it prefers a well-draining inorganic substrate, as the roots are easily susceptible torot. Sneed's cactus must be kept completely dry during itsdormant season in the winter months, and atmospheric humidity must be kept at a low. Regular watering may be done throughout the spring and summer once thegrowing season has resumed, provided the soil is well-drained. Fertilization requirements are simple, consisting of a high-potassium fertilizer during the summer growing season for Sneed's feed, and seed propagation is equally straightforward, with seeds sown after the last frost in spring typically germinating within one to two weeks provided they are well-ventilated and kept out of direct sun. Sneed's pincushion can also be propagatedasexually viaoffsets from the base of the plant.[11][12]
Media related toEscobaria sneedii at Wikimedia Commons
Data related toPelecyphora sneedii at Wikispecies