Opuntia humifusa

Opuntia humifusa, commonly known as the devil's-tongue,[1] Eastern prickly pear or Indian fig, is a cactus of the genus Opuntia present in parts of eastern North America.

Eastern prickly pear
Scientific classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Order: Caryophyllales
Family: Cactaceae
Genus: Opuntia
Species:
O. humifusa
Binomial name
Opuntia humifusa
(Raf.) Raf.
Opuntia humifusa in fruit by the beach at Welwyn Preserve, Glen Cove, Long Island, New York, October 2014

Description

As is the case in other Opuntia species, the green stems of this low-growing perennial cactus are flattened, and are formed of segments. Barbed bristles are found around the surfaces of the segments, and longer spines are sometimes present.[2] The flowers are yellow to gold in color, and are found along the margins of mature segments. The flowers are waxy and sometimes have red centers. They measure 4–6 cm (1 5⁄8–2 3⁄8 in) across. This cactus blooms in the late spring.

The juicy and edible red or purple fruits[3] measure from 3–5 cm (1 1⁄8–2 in). As the fruit matures, it changes colour from green to red, and often remains on the cactus until the following spring. There are 6 to 33 small, flat, light-colored seeds in each fruit.

Taxonomy

Some botanists treat this cactus as a variety of Opuntia compressa: hence Opuntia compressa var. humifusa, or a synonym of Opuntia compressa. Those recognizing this species treat Opuntia rafinesquii as a junior synonym.

Distribution

This species naturally occurs from arid areas of Montana southward to New Mexico, and eastward to the lower Great Lakes, and along the East Coast from the Florida Keys to coastal Connecticut.[4] Its distribution in Canada is limited to the Carolinian forest in southern Ontario, specifically in Point Pelee National Park.[5]

The Eastern prickly pear is the only native cactus species in Canada and is considered endangered, with only two small populations known to be persisting today.[5] Their population range in southern Ontario has diminished over time due to succession by larger woody vegetation which shade out the cacti.[5]

Habitat

This plant is very intolerant of shade and instead thrives in sunny, hot and dry environments with well-draining, sandy soil.[5] Opuntia humifusa will grow in open areas in sandy, rocky and coastal scrub habits. They are capable of surviving cool winters unlike many cacti, although harsh winter storms are known to cause habitat loss.[5]

  • Close-up of yellow barbed bristles and longer spines
  • The fruit of the eastern prickly pear in South Carolina
  • Eastern prickly pear growing wild in northern Illinois (partial shade)
  • Flowers
gollark: I had assumed this stuff was now ML-based and so you would just compare embedding vectors or something.
gollark: What are they eigenvectors *of*, exactly?
gollark: eigen is "own" or something, and apparently people prefer that over "characteristic vector/value".
gollark: Yes, the term comes from that for mysterious reasons.
gollark: (x is called an "eigenvector", and it might be nicer to think of the eigenvector as a vector which the matrix scales up by that eigenvalue, instead of transforming it in some other way)

References
  1. "Opuntia humifusa". Natural Resources Conservation Service PLANTS Database. USDA. Retrieved 23 July 2015.
  2. "4. Opuntia humifusa", Flora of North America
  3. Niering, William A.; Olmstead, Nancy C. (1985) [1979]. The Audubon Society Field Guide to North American Wildflowers, Eastern Region. Knopf. p. 436. ISBN 0-394-50432-1.
  4. Eastern Prickly Pear Opuntia humifusa (PDF) (Report). Natural Heritage & Endangered Species Program, Massachusetts Division of Fisheries & Wildlife. Archived from the original (PDF) on September 21, 2018.
  5. "Species Profile (Eastern Prickly Pear Cactus) - Species at Risk Public Registry". wildlife-species.canada.ca. Retrieved 2020-04-15.
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