Opuntiads of the USA

(by Joe Shaw and Dave Ferguson)

Mission

Opuntia Species

Opuntia Country No. 1
Opuntia Country No. 2
Opuntia Country No. 3
Opuntia Country No. 4
Opuntia Country No. 5

Opuntia Country with
Daiv Freeman

Opuntia County, Big Bend

World Opuntiads

Peru Cactus Trip

Northern Patagonia Cactus Trip

Northern Patagonia Sights

Notes from the Editors

Culture Notes

Literature

Editorial Board

News

WWW Links

Agave Photos

Opuntia mackensenii Rose

No photos are available. Read an early description of O. mackensenii.

Many workers do not recognize O. mackensenii and lump that taxon in with O. macrorhiza. However, Weedin and Powell have described the taxon clearly in Cacti of the Trans-Pecos and Adjacent Areas (pages 148-154) .

Dave Ferguson reports "O. mackensenii is very very similar to O. phaeacantha; it was renamed as O. edwardsii by the Grants (but their type specimen is a hybrid, so the name falls by the wayside - except for that particular hybrid).  It has 44 chromosomes (O. phaeacantha has 66), and it differs in minor details
spines usually white or nearly so
pads "greener and softer" looking
fruit averaging a bit rounder and richer in color (most often redder, sometimes pinkish, orange, green, etc.), and so on. 
It's all over the north half of Texas and reaches to Kansas, Missouri, Arkansas, New Mexico, and Oklahoma.  Usually is confused with O. macrorhiza in Texas, because the books don't have a 'slot' for it."

O. mackensenii is described on pages 308-312 in Contributions from the National Herbarium, Vol 13, 1909-1912 (see: Notes and descriptions of North American Opuntia, page 309).