Opuntia cespitosa, Common Eastern Pricklypear

Opuntia cespitosa
Opuntia cespitosa

Rafinesque, Bulletin Botanique 2: 216, 1830

Neotype; Herbarium; Herbarium; Herbarium; Herbarium (as O. humifusa); Herbarium (with O. nemoralis); Herbarium (as humifusa); Herbarium (as humifusa); Herbarium (as O. humifusa); Herbarium; Herbarium; Herbarium (as O. humifusa); Herbarium

See O. humifusa   See O. lata    See O. mesacantha

Original Description

What is Opuntia cespitosa?

Opuntia cespitosa is a member of the Opuntia humifusa group (O. humifusa s.l.) and closely resembles O. humifusa, with which it was long synonymized and thus frequently overlooked by botanists. It also shares morphological similarities with the western species O. macrorhiza.

Details

Cladodes are generally glaucous-gray and typically bear 0–2 spines at scattered areoles. When present, spines are either both erect or both deflexed, and only central spines are produced. In contrast to O. mesacantha, O. cespitosa lacks strongly retrorsely-barbed spines. This feature also distinguishes it from O. humifusa, which is typically unarmed. The cladodes usually form chains that lie parallel to the ground surface and become wrinkled by late summer or fall.

Flowers are yellow with conspicuous red centers. Filaments are yellow, anthers are pale, the style is white, and the stigma is white or pale yellow. The fruit is clavate.

O. cespitosa is tetraploid.

Other Notes

Opuntia cespitosa is the most widespread Opuntia species in the eastern, southern, and midwestern United States, with confirmed records from Alabama, Arkansas, Connecticut, Georgia, Illinois, Indiana, Massachusetts, Maryland, Michigan, Missouri, Mississippi, New York, Ohio, Virginia, and West Virginia. It also occurs at Point Pelee, Ontario, Canada. Recent work by Paul D. Adanick indicates that O. cespitosa is present at numerous locations in Tennessee and Kentucky, though it may not be abundant at any one site.

Three herbarium specimens from Bucks County, Pennsylvania—cataloged as O. humifusa and/or O. compressa—are housed at the Academy of Natural Sciences of Drexel University and are accessible through SERNEC. Reports also suggest its presence in Hunterdon County, New Jersey, and elsewhere in Pennsylvania. O. cespitosa commonly inhabits rocky areas but is also found in dry, well-drained soils.

Various relevant scientific papers have reported on this Opuntia: Majure, 2014; Majure et al., 2012; Majure and Ervin, 2007. O. cespitosa resembles O. macrorhiza and is related to that taxon. 

Unlike O. cespitosa, other southeastern Opuntia species almost always have all-yellow flowers. 

Also, see Holmes (2016), Morphological and Ecological Characterization of Opuntia Miller on the Coast of South Carolina

The Flora of the Southern and Mid-Atlantic States (2015) reports:

Vegetatively, it is most similar to Opuntia mesacantha ssp. mesacantha, from which this allopolyploid may be partially derived, although floral features are quite different, and O. cespitosa does not have the strongly retrorsely-barbed spines common in O. mesacantha. This species also can be confused with certain forms of O. macrorhiza, another putative parent of O. cespitosa; both species have yellow inner tepals basally tinged red adaxially.

 

6 thoughts on “Opuntia cespitosa, Common Eastern Pricklypear”

  1. David A Schaeffer

    There are cliffs overlooking the Delaware River just N of Milford, NJ, with a large population of what I always assumed to be O. humifusa. However, these plants occasionally exhibit spines. Thoughts?

  2. Bill Harms

    If it has spines and the base of the tepals are red or orange, or if they have a reddish/orangish tint, it is possible they are O cespitosa.

  3. Joseph

    Hi Botany Bill,
    Thanks for visiting our website.

    Your description sounds like O. cespitosa to me if it is east of the Mississippi River.
    West of the river (somewhere) O. macrorhiza begins. The two are very similar and a colleague calls them all O. macrorhiza, east or wet.
    The red in the center of the flower is very telling. Much depends on the size of the plant, large woody plants would not be O. macrorhiza or O. cespitosa.

    Joe Shaw

  5. Derek Stephen Hollingshead

    “Is the only Opuntia that occurs in eastern Canada (far southern Ontario).”

    Hey Joe!

    I think this anecdote can be revised for both the Kaladar, ON O. fragilis and Thousand Islands, ON O. polyacantha populations.

    Hope you are doing well :)

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