Identifying Prickly Pear Opuntias (A-E)
Opuntias are the pricklly pear cacti. The plant is composed of flat pads. Glochids are present at the aeroles. Large spines are usually, but not always present. Classification at the species level is often difficult. The opuntias hybridize creating intergradations between species. For example, in the west foothills of the Sandia Mountains at 6,200 foot elevation Opuntia engelmanii, Opuntia polycantha, and Opuntia erinacea are common. Clear examples of each species abound. Examples of species with characteristics intermediate between erinacea and polycantha are also observed. Similiar descriptions are noted in many references.
To differentiate between species the most important characteristic is location. Where is this prickly pear observed? Next most important is the overall plant size and height. After considering the above the characteristics below can be considered in sequence.
aurea Golden Pricklypear |
aureispina Rio Grande Pricklypear |
aciculata |
atrispina |
Beaver Tail Prickly Pear. |
Pancake Pricklypear. |
chisosensis Chisos Mountains Prickly Pear. |
xcurvispina |
Engelmann's Prickly Pear |
|
| N arizona border | Big Bend, Texas | East of Big Bend, Texas | near and at Big Bend, Texas | SW arizona, SE Calif. | South Arizoa,SW New Mexico, E ca, S Nev. | Big Bend, Texas | small, W Az, E ca, S Nev. | South Texas, cent to south NM, South to W Az, E ca. S Ut. | |
| Habit | low clumps, sandy soils. PJ woodlands. | shrubs to small trees. to 1.5 meters. | shrub to a meter. spineless forms cultivated. |
shrubs to a meter. grassland, limestone hills. | clumps to 40 cm. | shrubs to trees 2.5 meters. well defined trunk. | Shrubs to 1 meter. pine, mixed conif grasslands, 4,500-7,500 feet. | Shrubs about a meter, desert grassland, oak and juniper woods, sandy or gravely slopes, 3,300-5,000 feet. | Shrubs to small trees, 1-3 meters. |
| Pad Size | 6-15 by 5x12 cm. mean 9.5-8 cm. bright green |
8-12 by 8-12 cm. mean 10x10cm. | 13-20 by8-10 cm, mean 16x9 cm. | 10-15 to 7.5-12 cm. mean 12.2x12 cm. | 5-22x2-13 cm, mean 11x5 cm. | 13-21by 12-19 cm. mean 16x15 cm. | 15-30 by 12-25 cm. mean 21-17 cm. | 12-22 by 12-20 cm., mean 16x16 cm. | 15-40 by 10x40 cm.mean 21-20 cm. |
| Aeroles | 7-11 across midstem, mean 9 | 6-8 across midstem, mean 7.
|
4-7 per row across midstem. | 5-7 across midstem. | 4-16 per row, mean 8. | 7-10 across midstem. basal ridge. | 5-7 across midstem. | 6-9 across midstem. | 5-8 across midstem. |
large Spines |
absent to 1 in a few distal aeroles. | 4-12 per aerole.bright yellow to org, brown at base. | absent to 2 per aerole. yellow to mottled brown. | 4-7 mostly in distal aeroles.Black to brown yellow tips. | usually absent , occ. present distal aeroles. | vary, absent to distal to all aeroles. 0-12 per aerole | 1-5 per aerole. | usually present 0-9 per aerole. | 0-6 per aerole. |
| Pad Surface | Bright green, aeroles look extruded. |
|
green, smooth. | smooth, green to maroon. | |||||
Spine length |
to 10 mm. | 20-60 mm, mean 35 mm. smaller spines to 20 mm. | to 50 mm. | larger 30 mm, smaller < 10 mm. | yellow, 5-20 mm. | 40 mm. Main and curvey smaller spines. | 20-70 mm. | 5 cm, spreading esp. on stem margins. | 10-30 mm. |
| Glochids | dense cresent adaxial margin and subapical tuft. | narrow row encircling aerole. | evenly spaced and radiating. | bushy cresent adaxial edge and subapical tuft. | nearly fill aeroles. | dense on adaxial margins. | cresent at adaxial aerole margin. rough subapical tuft. | dense in marginal cresent, obscured by long dense tan to brown wool. | scattered, encircling aerole. Irregular lengths to 10 mm. |
flower Color Size |
yellow 25-30 mm. |
yellow w orange to red base. 35 mm. | yellow, orange, red. 30 mm. |
yellow fade to apricot. 25 mm. |
pink to magenta 30 mm. |
yellow, reddish basal blush. 25 mm. |
pale yellow 27 mm. | yellow, 30 mm. | yellow, buff, orange, pink, red. |
Filaments Anther |
white to yellow yellow |
yellow to pale green. pale yellow. |
cream to pink yellow |
yellow yellow |
red magenta yellowish |
white to yellow white,yellowish, pale green. |
pale green yellow |
yellow yellow |
white to cream white to cream |
Stigma Style |
lobes green white |
lobes green yellow. |
lobes dark green cream to pink. |
greenish yellow to yellow whitish |
white to cream white to pink |
white, yellowish, pale green. white, yellowish, pale green. |
lobes green yellow
|
greenish white, white |
yellow green to green white to cream |
Fruit Spines |
dry, 25x17 mm. no spines,12-18 aeroles |
begin fleshy dry fast. 35x25 mm. several rigid yellow spines. |
dark red, juicy spineless. |
red yellow, juicy, spineless. | tan,dry, spineless, 30x20 mm. | red, barrel shaped, fleshy.45x30 mm. spineless. | reddish purple, juicy, spineless, barrel shaped. | red, greenish flesh, fleshy, spineless. 40x20 mm. |
red to purple, juicy, spineless. 60x28 mm. |
| Location | Arizona north of Rim, Southern Utah. | Texas species, primarily sw near Rio Grande | South Texas east of Big Bend. | near and east of Big Bend | SW arizona, SE california, S Nevada, SW Utah. | Southern Arizona below rim, SE NM, S Nev., SE Cal. | Texas near Big Bend. Chisos Mountains. | narrow triangle where N Ariz, E ca, South Nev. meet. | Swath across south Texas, central and South NM, South Arizona. In south Utah and E Ca. |
Seeds
|
large, 10 mm dia. | tan 5 mm. | 3.3 mm. | 4 mm. | yellowish 3 mm. | yellowish 3.5 mm. | yellow, 4 mm. | yellowish 4 mm. | tan to greyish 4x3 mm. |
| Varieties | none | none | none | none | four | none | none | five | |
hybrids
|
with polycantha and phaecantha | with Opuntia Santa Rita and Opuntia phaecantha. | curvispina is a hybrid of chlorotica and phaecantha. |