Opuntia humifusa
Cactaceae
Description:
Pollen monads, size class large to very large, diameter 92-110 μm, shape sphaeroidal, polygonal, apolar, equatorial shape circular; aperturate, pantoporate; ornamentation lophate (fenestrate), lacunae hexagonal, reticulate; tectum semi-tectate. Viscin absent.
Pollination Biology:
The prickly pear has pads will break off and start new plants, which at least in the midwest is the main method of reproduction. Flowering is apparently an optional response when resources are abundant, and in many populations flowers have never been observed (Hilty 2010).
This species is visited by a variety of long-tongue and short-tongue bees. Long-tongued bees suck nectar or collect pollen, while short-tongued bees collect pollen only; the larger bees are more likely to cause cross-pollination .
Bumble bees are the main pollinators in Canada, where the species is endangered, but the flowers are also visited by three leaf-cutting bees (Megachile frigida, M. latimanus and M. texana) and one other bee species (Agapostemon splendens) (Kevan and Aiello, 2001, 2002). Cross pollination is necessary to produce viable seed, and the more visitors the more seed produced (Kevan and Aiello 2001, 2002).
The stamens move inward when touched, which may help spread pollen on a visiting insect (Schlindwein and Wittmann 1997).
Tropicos Pollen Voucher:
Yatskievych 89-147
Links:
Platyopuntia
USDA Plants – Opuntia humifusa
Illinois Wildflowers (Hilty 2010)
Species in Missouri:
Opuntia engelmannii Salm-Dyck ex Engelm.
Opuntia humifusa (Raf.) Raf.
Opuntia macrorhiza Engelm.
Opuntia polyacantha Haw.
References:
COSEWIC. 2010. COSEWIC assessment and status report on the Eastern Prickly Pear Cactus Opuntia humifusa in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. x + 30 pp. (www.sararegistry.gc.ca/status/status_e.cfm).
Davis, O.K. and R.S. Anderson. 1987. Pollen in packrat (Neotoma) middens: Pollen transport and the relationship of pollen to vegetation. Palynology. 11(1):185-198.
Doyle, J.D. 1990. Systematics of the Opuntia humifusa complex. Ph.D. Dissertation. The University of North Carolina, Chapel Hill, NC.
Hilty, J. Editor. 2010. Insect Visitors of Illinois Wildflowers. World Wide Web electronic publication. flowervisitors.info, version (04/2010).
Kevan, P.G. and R. Aiello. 2001. Reproductive Ecology and Mutualism with Opuntia humifusa, in Point Pelee National Park. Unpublished Manuscript.
Kevan, P.G. and R. Aiello. 2002. Pollination & seed set mechanisms of Opuntia humifusa, in Point Pelee National Park. Unpublished report. 10 pp.
Kevan, P.G., J.W. Boone, R. Aiello and T. Hisatomo. 2003. Fruit and Seed Dispersal biology of Opuntia humifusa, in Point Pelee National Park: Report for Field Seasons 2001, 2002 & 2003. 18 pp.
Kevan, P.G., C. Sheffield, T. Hisatomo and J. Boone. 2003. List and Notes on Ranges and Nesting Habits of the Pollinators of Opuntia humifusa, in Point Pelee National Park. pp. 1-5.
Kevan, P.G., C. Sheffield, H. Taki and J. Boone. 2004. List and Notes on Ranges and Nesting Habits of the Pollinators of Opuntia humifusa, in Point Pelee National Park. Unpublished report.
Padron B, Traveset A, Biedenweg T, Dıaz D, Nogales M, and J.M. Olesen. 2009. Impact of Alien Plant Invaders on Pollination Networks in Two Archipelagos. PLoS ONE 4(7): e6275.
Pinkava, D.J. 2003. Opuntia. In: Flora of North America Editorial Committee, eds. 1993+. Flora of North America North of Mexico. 12+ vols. New York and Oxford. Vol. 4, pp.123-148.
Schlindwein, C. and D. Wittmann. 1997. Stamen movements in flowers of Opuntia (Cactaceae). Plant Syst. Evol. 204:179-193.