Opuntia eburnispina

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

Herbarium

Original Description

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, and some botanists consider that O. eburnispina is synonymous with O. austrina

Details

O. burnispina is prostrate, prickly pear, 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, 4-5 mm long, pale green, recurved spreading. The spines relatively stout, 2-4 at an areole or sometimes solitary, 1-2 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). 

Ploidy is unknown. 

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 

Original Citation

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 also 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.

There is typically one yellow flower per cladode. The fruit is gently tuberculate, urn shaped,  and rounded at the base. 

Both diploid and tetraploid forms of O. abjecta have been reported. 

Other Notes

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

 

 

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); Painting (Mary Emily Eaton)

Original Description

What is Opuntia fusco-atra?

Little is known about this prickly pear. It is reported to grow west of Houston, Texas. 

Details

This Opuntia is purported to have stout brown, almost black, spines on small joints. The cladodes are 5-7 cm long and the spines are 2-3 cm long. The spines may be of two sizes with the lower one 1.5 cm long. 

Flowers are yellow and about 3.5 cm in diameter. The ovary is 2.5 cm long and slender. 

Ploidy is unknown. 

Other Notes

Some botanists consider that O. fusco-atra is a form of O. nemoralis

 

 

 

Opuntia atrocapensis

Opuntia sp.
Opuntia sp.

Small, Manual of the Southeastern Flora 905, 1933

Herbarium

Original Description

What is Opuntia atrocapensis?

Opuntia atrocapensis is a prickly pear cactus known from the sand dunes of Monroe County, FL. It resembles O. ammophila

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. 

Ploidy is unknown. 

Other Notes

Some botanists consider that O. atrocapensis is synonymous with O. ammophila

Opuntia mesacantha

Opuntia mesacantha
Opuntia mesacantha

Rafinesque, Bulletin Botanique 1: 216, 1830

(Also Opuntia mesacantha Raf ssp mesacantha Majure, Phytotaxa 290, 1: 1–65 )

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

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

Original Description 

What is Opuntia mesacantha?

Opuntia mesacantha is a southeastern prickly pear found in Mississippi, Alabama, Georgia, and Florida, South Carolina, and North Carolina on the Atlantic Coastal Plain Fulf Coast Barrier Islands. It is absent in the Florida peninsula. It resembles O. humifusa, O. lata, 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.  Like other eastern prickly pears, O. mesacantha colonizes sandy or rocky areas that become dry between rains. 

Opuntia mesacantha is tetraploid. 

Other Notes

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)

Original Description

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. The plant is prostrate to 20-30 cm tall. Large plants may be 1.0 m across. The cladodes are oval or obovate and may be more or less pointed at both ends or round. Cladodes may be 10 cm across and up to 12(15) cm long. Areoles are raised. O. xanthoglochia has yellowish glochids, sometimes numerous and prominent and up to 1 cm inch long.

The flowers are lemon yellow with red or brownish-red centers, about 7 cm in diameter. However, flowers are variable, sometimes with no red and other times with excess red. Other times the red is confined to the mid-rib of the tepals. Filaments are greenish, and the style and stigma are white or pale yellowish. The ovary is long and slim. 

O. xanthoglochia is diploid.

Other Notes

O. xanthoglochia may be considered a diploid form of O. macrorhiza s.l. 

See more about the ploidy of O. xanthoglochia.

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

Original Description

What is Opuntia cespitosa?

Opuntia cespitosa is a prickly pear 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. O. cespitosa also has similarities with the western species, O. macrorhiza

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. 

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 tetraploid.

Other Notes

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, 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.

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 Southeast Opuntia spp. have all-yellow flowers. 

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

Original Description

What is Opuntia diploursina?

Opuntia diploursina was described from near Meadview, AZ. It has a limited range. Additionally, it has similarities with O. polyacantha erinacea and O. trichophora

Details

O. diploursina grows to (15)20-45 cm tall with upright branches of 1-4(6) cladodes. Cladodes are narrowly obovate to elliptic, 9-14 cm long,and (4)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. Overall, the plant is very shaggy with its numerous long spines. 

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 10-15 spines in each fruit areole–10 mm long or longer. The fruit is many seeded. At 9-10 mm in diameter seeds are large, and they have pronounced rims. 

O. diploursina is diploid.

Other Notes

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 speculated that O. diploursina represents an ancient diploid ancestor of O. polyacantha erinacea. Hybrids between this Opuntia and O. basilaris and have been reported.

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