Griffiths, Annual Report of the Missouri Botanical Garden 22: 34, 1911
What is Opuntia tardospina?
Opuntia tardospina is a large prickly pear cactus first reported from the Lampasas, Texas region. Griffiths reported that this Opuntia was an unusual cactus for several reasons, not the least of which were the prominent areoles.
Cladodes are green or bluish-green and up to 24 by 30 cm, subcircular to obovate. Though spines are mostly absent, some yellow ones do occur that recurve or slope downwards. Under garden conditions, spines may be frequent. The glochids are numerous and prominent, up to 12 to 15 mm long, sometimes even on pads of the current year. Areoles are prominent, up to 1 cm across in old growth and raised by 2 to 4 mm. Finally, the prominent glochids can cover old stems as in the case of O. chlorotica santa-rita.
Flowers are yellow and fruit is broadly obovate to pyriform, with areoles about 15 mm apart.
Ploidy is unknown.
O. tardospina differs from O. aciculata in several ways. The pads are bluer and thicker, and the trunks have glochids. The plants in these photos have curved leaves on the ovaries, which is a feature of O. cacanapa.
O. tardospina is essentially never reported. Likely this is due to the tendency to interpret any large Texas Opuntia as O. lindheimeri or O. engelmannii.