Opuntia eburnispina

Britton and Rose, The Cactaceae vol IV, 260. 1923

Herbarium

What is Opuntia eburnispina?

Opuntia eburnispina is a rarely found prickly pear cactus from Cape Romano, Florida. It may be related to O. humifusa or O. austrina. Some botanists consider that O. burnispina is a variant of O. austrina

Details

O. burnispina is prostrate, widely branched and forming mats on dune sands. It has tuberous roots. The pads are oval or suborbicular, varying to broadest above middle, thickish, 6 to 13 cm. long, pale green, somewhat shining, especially when young. The leaves ovoid-subulate, 4 to 5 mm. long, pale green, recurved spreading. The spines relatively stout, 2 to 4 at an areole or sometimes solitary, 1 to 2 cm. long, ivory white with yellowish tips when young, becoming dark gray, not spirally twisted, greenish when wet.

Flowers are few; the ovary is obconic; the sepals are triangular, green, 5 to 7 mm. long. The flower is clear yellow, 4 to 5 cm wide. The petals are few, narrowly cuneate, often minutely pointed, and the berries obovoid about 2 cm. long or less. The seeds, at (ca. 3 mm), are smaller than those of O. austrina (ca. 5 mm). See the original description

Opuntia abjecta

Opuntia abjecta
Opuntia abjecta

Small ex Britton and Rose, The Cactaceae, Descriptions and Illustrations of Plants of the Cactus Family 4: 257, 1923

Herbarium; Herbarium

What is Opuntia abjecta?

Opuntia abjecta is a prickly pear cactus that occurs in the lower Florida Keys where it grows on bare limestone or where a bit of sand or humus has accumulated.

Details

This Opuntia grows up to 15 cm tall and forms multi-branched mats. The cladodes are 2-8 cm long and thickish. While not fragile, the cladodes are not firmly attached to each other. The longest spines on this prickly pear may be 4-5 cm. Like O. zebrina and unlike O. pusilla, this cactus has teardrop-shaped leaves. The seeds of O. abjecta are about 4 mm in diameter.

Some botanists have accepted this Opuntia as a synonym of O. triacantha. We accept O. abjecta as a taxon independent from O. triacantha (see the paper by Majure et al). The type locality is Big Pine Key, FL.

See the original citation. Both diploid and tetraploid forms of O. abjecta have been reported. 

 

Opuntia fusco-atra

Opuntia sp.
Opuntia sp.

Engelman. Proceedings of the American Academy of Arts and Sciences 3: 297, 1856

Herbarium (as O. nemoralis/macatee); Drawing (Drawings/prints associated with USPRR reports & photographs/archival material; plate XI)

See the original description.

 

Opuntia atrocapensis

Opuntia sp.
Opuntia sp.

Small, Manual of the Southeastern Flora 905, 1933

Herbarium

What is Opuntia atrocapensis?

Opuntia atrocapensis is a prickly pear cactus known from the sand dunes of Monroe County, FL. The type specimen (herbarium specimen) has never been found. Some botanists consider that O. atrocapensis is synonymous with O. astrispina.

Details

O. atrocapensis forms prostrate, much-branched plants, sometimes resurgent a the tips. Cladodes are obovate, elliptical, or broadly elliptical, 5-10 cm long. Usually there is one spine per  areole. The longest spines are 2-3 cm. The fruit is narrowly obovoid to 3.5 cm long and reddish purple. There are many seeds that are 3-3.5 mm across. A new herbarium specimen for this Opuntia has been designated the neotype. See the original description.

 

Opuntia mesacantha

Opuntia mesacantha
Opuntia mesacantha

Rafinesque, Bulletin Botanique 1: 216, 1830

(Also Opuntia mesacantha Raf ssp mesacantha Majure)

See O. cespitosa    See O. humifusa    See O. lata

Neotype; Herbarium; Herbarium; Herbarium; Hebarium (as O. humifusa); Herbarium; Herbarium; Herbarium; Herbarium; Herbarium; Herbarium

 

What is Opuntia mesacantha?

Opuntia mesacantha is a southeastern prickly pear found in Georgia, Alabama, and Florida and adjacent areas in the southern Piedmant and Gulf Coast Barrier Islands. It is absent in the Florida peninsula. It resembles O. humifusa and O. cespitosa but has distinct differences; see Majure, 2014 and Majure et al, 2012

Details

O. mesacantha is a prostrate plant that may branch in all directions to 1 m across. Cladodes may be spined or unspined and are smooth in outline, obovate or rotund, occasionally elliptical. Spines are stout (0.95-1.3 mm in diameter). 

Flowers are pure yellow with no red. Fruits are reddish at maturity. Seeds are 5.0-5.9 mm long. 

O. mesacantha and O. lata are difficult to differentiate in the field, but Adanick et al., 2019 developed a method to measure stomates in the field and differentiate the two taxa easily.  See the original descriptionO. mesacantha is tetraploid, whereas the related O. lata is a diploid. Like other eastern prickly pears, O. mesacantha colonizes sandy or rocky areas that become dry between rains. 

Concerning the differences between O. mesacantha and O. humifusa, The Flora of the Southern and Mid-Atlantic States (2015) reports:

O. humifusa is an allotetraploid (2n=44), cryptic species that is most easily confused with O. mesacantha ssp. mesacantha, from which it can be separated by its lack of spines…and generally increased number of areoles per diagonal row across the cladode face at midstem (4-5 vs. 3-4 in O. mesacantha), generally inserted glochids (vs. exerted in O. mesacantha), and smaller seeds (4.0-4.6 mm long in O. humifusa vs. 5.0-5.9 mm long in O. mesacantha) with a smooth funicular envelop (instead of the upraised funicular envelope in O. mesacantha ssp. mesacantha).

Opuntia xanthoglochia

Opuntia xanthoglochia
Opuntia xanthoglochia

Griffiths, Annual Report of the Missouri Botanical Garden 21: 166, 1910

Holotype; Painting (Mary Emily Eaton); Painting (Mary Emily Eaton)

What is Opuntia xanthoglochia?

Opuntia xanthoglochia is a prickly pear cactus cactus found in central Texas, east of Austin although it may range into other areas.

Details

O. xanthoglochia resembles O. macrorhiza, and the cactus has been conflated with that species. The plant is prostrate to 8- to 12-inches tall. Large plants may be 3-ft across. The cladodes are oval or obovate and may be more or less pointed at both ends or round. Cladodes may be 4-inches across and up to 5(6)-inches long. O. xanthoglochia has yellowish glochids, sometimes numerous and prominent and up to 3/8-inch long.

The flowers are yellow with a red centers.

See the original description. Unlike O. macrorhiza, O. xanthoglochia is diploid.

See the scientific paper.

Opuntia cespitosa

Opuntia cespitosa
Opuntia cespitosa

Rafinesque, Bulletin Botanique 2: 216, 1830

Neotype; Herbarium; Herbarium; HerbariumHerbarium (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

What is Opuntia cespitosa?

Opuntia cespitosa is a prickly pear included in the O. humifusa group of cacti (O. humifusa s.l.). O. cespitosa resembles O. humifusa and has long been overlooked by botanists because it was considered synonymous with that species.

Details

O. cespitosa cladodes generally appear glaucous-gray. Cladodes have 0-2 spines that are either both erect or both deflexed. Only centrals are produced. O. cespitosa does not have strongly retrorsely-barbed spines, which are common in the related O. mesacantha. The spines of O. cespitosa place it in contrast with O. humifusa, which lacks spines. Typically,  the chains of cladodes are parallel to the ground surface. As with related plants (i.e., O. humifusa s.l.), the cladodes become wrinkled in fall. 

Unlike O. humifusa, O. cespitosa has yellow flowers with red centers. Filaments are yellow and anthers are pale. The style is white and the stigma is white or pale yellow. The fruit is clavate. 

O. cespitosa is the most common Opuntia species in the eastern states though it has traditionally been subsumed into O. humifusa and was not noticed. It is present in multiple eastern, southern, and midwestern states including AL, AR, CT, GA, IL, IN, MA, MD, MI, MO, MS, NY, OH, TX, VA and WV. It is the only Opuntia that occurs in eastern Canada (far southern Ontario). Recent work by Paul D. Adanick shows that this Opuntia occurs in many locations in TN and KY but that it may not be numerous at any specific location. It is often found in rocky situations but also occurs in dry soils. See the original description. O. cespitosa is tetraploid.

Various relevant scientific papers have reported on this Opuntia: Majure, 2014; Majure et al., 2012; Majure and Ervin, 2007

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.

Opuntia diploursina

Opuntia diploursina
Opuntia diploursina

Stock, Hussey, and Beckstrom, Cactus and Succulent Journal (U.S.) 86(2): 35, 2014

Herbarium; Herbarium; Herbarium; Herbarium; Herbarium; Herbarium

Similar to Opuntia trichophora

What is Opuntia diploursina?

Opuntia diploursina was described from near Meadview, AZ. It has similarities with O. polyacantha erinacea and O. trichophora

Details

O. diploursina grows to about 45 cm tall with upright branches of 1-4(6) cladodes. However, O. diploursina is often 20 cm tall. Cladodes are narrowly obovate to elloptic, 9-14 cm long, and 6-9 cm wide. As in O. polyacantha erinaceae and O. trichophora, the areoles are many and close together. Often there is one major spine per areole, especially in the second year. Spines are straw-colored or yellow-tan and flexible, 2-10 cm long. There are many minor spines appressed to the cladode surface and crossing over other areoles. 

The yellow flowers are 6-7 cm long, but they can have a peach-colored cast to them due to a pinkish blush on many tepals. The style is white and the stigma is green. Filaments are white. Fruit is dry. There may be about 15 spines in each fruit areole–10 mm long or longer. The fruit is many seeded with propagules 9-10 mm in diameter with pronounced rims. 

A major and important difference between O. polyacantha erinaceae and O. diplourisna is polidy. The former is tetraploid whereas the latter is diploid as is O. trichophora.

O. diplourina is related to O. trichophora. O. diplourisna differs from  O. trichophora in being more upright, the presence of more minor spines that are more closely appressed to the cladode surface, and more and more flexible spines on the fruit. 

The original authors proposed that O. diploursina represents an ancient diploid ancestor of O. polyacantha erinacea but did not elaborate. Hybrids between this Opuntia and O. basilaris and have been reported. Read the original description. O. diplourisna is diploid.

Permission to reproduce the original description was provided by the Cactus and Succulent Society Journal.

Opuntia nemoralis

Opuntia nemoralis
Opuntia nemoralis

Griffiths, Monatsschrift fur Kakteenkunde 23: 133, 1913

Herbarium; Herbarium; Herbarium (with O. cespitosa); Herbarium; Herbarium (with O. cespitosa); Herbarium (with O. cespitosa); Herbarium; Herbarium

by Joe Shaw and Barry Snow

What is Opuntia nemoralis?

Opuntia nemoralis is a southern Midwest prickly pear that has been observed in saline prairies, sandhills, and shale outcrops in Arkansas, Louisiana, and Texas.

Details

Plants observed north of Lake Ouachita in Arkansas were glaucous/pruinose, especially in winter, whereas plants near Longview, Texas had purple areoles that were striking. Plants may sprawl to 1 m across and reach 30 cm tall. The cladodes are ovate to obovate, 4.5 cm wide by 9 cm long or smaller. Older cladodes are wrinkled. Glochids are yellow. 

Flowers are yellow with relatively few tepals. The fruit is small, about 17 mm thick and 32 mm long. Fruit pulp is slightly reddened. 

O. nemoralis is uncommonly encountered. O. nemoralis has been erroneously conflated with O. humifusa. It is different from O. humifusa although it is a member of that clade. See the original description. O. nemoralis is tetraploid.

Opuntia columbiana

Opuntia columbiana
Opuntia columbiana

Griffiths, Bulletin of the Torrey Botanical Club 43: 523, 1916

Lectotype; Lectotype; Herbarium; Herbarium; Herbarium; Herbarium

What is Opuntia columbiana?

Opuntia columbiana is a prickly pear cactus that occurs in northeast Oregon and southeast Washington. Opuntia columbiana is referred to as O. × columbiana by some botanists (Anderson, 2001) who maintain that this Opuntia is a prickly pear hybrid between O. polyacantha erinacea and O. fragilis

Details

Some botanists report that O. columbiana resembles an O. fragilis hybrid over part of its range only. Perhaps this Opuntia represents two or more cactus species that need more study. Though it may have hybrid origins, at least some populations of this prickly pear appear to be stable and self-reproducing if only clonally. This fact suggests that O. columbiana may be a stand-alone taxon and we regard it as such lacking other information. Also interesting is that some cladodes (on many plants) are often narrowly obovate (about 5 × 10-15 cm), unlike either of the proposed ancestral species.

The plants form low mats with fragile cladodes that are flattened, narrowly to broadly obovate, and fragile. Second year growth may be yellowish green. Major spines are present in most areoles, reflexed to porrect and yellowish to gray-white to brown, (20)25-40(50) mm long. Radial spines are also present. 

Flowers are yellow, 30-50 cm across. Filaments are red or brownish-red, anthers are yellow. The style is white and the stigma is green. Fruits are seldom set. Seeds are tan and 5-7 mm across. The protruding girdle is 1-1.5 mm. See the original description. O. columbiana is hexaploid.