|Key tree cactus, Keys tree cactus|
|(Lemaire) Byles and Rowley|
The following Participating Institutions are custodians for this species in the CPC National Collection:
Fairchild Tropical Botanic Garden
The conservation of Pilosocereus robinii is fully sponsored.
Jennifer Possley contributed to this Plant Profile.
The keys tree cactus is unlike any other plant in Florida. It is a true tree, with mature individuals possessing differentiated trunks and branches (Avery 1982). Plants can reach as high as 10 m, and may have dozens of spreading branches (Ward 1979), though most of the larger plants have been destroyed by development and hurricanes (USFWS 1986). The showy, 6 cm-long flowers are reported to smell like garlic (Hennesey and Habeck 1994). Although first discovered in the early 1800s, this species was very little studied until 75 years later (Small 1917), due in part to both its isolation from civilization and the awkwardness of making herbarium specimens of such a large cactus.
Distribution & Occurrence
Rocky tropical hardwood hammocks (USFWS 1986)
|Populations: 9 in Florida (FNAI 1998), 1 unconfirmed in Cuba (Adams, undated report)
Individuals: 624 in the Keys (Adams and Lima 1994), and an unknown number in Cuba
Conservation, Ecology & Research
Other possible threats include canopy closure, salt water intrusion, drainage, competition, and accumulation of soil
Natural History: Information on population age class, growth rates, and architecture is contained in Adams and Lima (1994). Dr. Peter Stiling, of the University of South Florida, may be continuing natural history research.
Predation: Adams and Lima (1994) noted ants and cardinals predating on the seeds and fruit, respectively.
Hennessey, M. K. and D. H. Habeck (1994). "Observations on reproduction of an endangered cactus, Cereus robinii (Lemaire) L. Benson." Florida Scientist 57: 93-101.
This rare cactus is subjected to mosquito insecticide spraying which has an unknown effect on its pollinators. No pollinators were observed, so cross pollination by animals remains unconfirmed. Its floral biology strongly suggests pollination by bats or moths. Pesticide spraying could have impacts on its reproductive cycle.
The National Wildlife Refuge and USFWS protect the land containing the largest population of the Keys tree cactus, but they do not regularly monitor the population. FDEP conducts periodic monitoring of the populations on its lands.
A clear summary of the status of the Keys tree cactus on private lands.
Outplanting of the cactus onto sites where it currently or historically is/was found.
Research on the effects of light levels, salt water, organic matter or competition.
If an outplanting were to take place, seeds need to be collected and used to propagate seedlings for outplanting.
Hennessey, M.K.; Habeck, D.H. 1994. Observations on reproduction of an endangered cactus, Cereus robinii (Lemaire) L. Benson. Florida Scientist. 57: 93-101.
Kartesz, J.T.; Gandhi, K.N. 1991. Nomenclatural notes for the North American Flora VIII. Phytologia. 71, 4: 269-280.