Harrisia fragrans

This is an erect or spreading cactus with narrow, long stems which can well exceed one meter in length, at times approaching five meters.[1][2] It is covered in long, yellow or yellow-tipped spines which may be up to 4 centimeters long.[2] It produces enormous tubular flowers up to 20 centimeters long which are sweet-scented and white to pinkish in color.[2] They bloom at night. The fruit is spherical and red or orange in color, measuring up to 6 centimeters wide. The fruits are a favorite food of local birds,[2] which likely help to disperse the seeds.[3] The cactus has been noted to live at least 19 years, and in general has low fecundity; older, larger plants are more likely to survive, and they have higher fecundity, as well.[3] Small plants may benefit from growing with nurse plants.[4]

The plant's favored natural habitat is mostly coastal hammocks with some shade, as the cactus can become desiccated in full sun.[3] Coastal hammocks of this kind have become uncommon as they have been cleared for development and heavily fragmented.[3]

There are ten confirmed occurrences of the plant, nine of which occur around Savannahs Preserve State Park in St. Lucie County and totalled 2150 individuals in the year 2002.[3] The tenth confirmed occurrence is at the Canaveral National Seashore in Volusia County, and it contains about 96 plants.[3] An occurrence has been reported in Indian River County, but it has not been confirmed.[3] The cactus once grew in at least two places in Brevard County, but these populations have been extirpated.[3]

Remaining populations of the cactus can now be found in sandy scrub habitat.[3] The remaining habitat is degraded with the overgrowth of invasive plant species such as love vine (Cassytha filiformis).[3] While the cactus does not like full sun, it also cannot tolerate being shaded out by brush.[3] Other threats to the plant have been all-terrain vehicles, herbicides, feral pigs, and hurricane damage from wind and falling branches.[3] Populations have been vandalized with machetes.[3] Cacti have died from being buried in sand, and have been stolen by cactus enthusiasts and collectors.[3] A scale insect, Diaspis echinocacti, sometimes eats the stems of the cactus, and some sort of caterpillar has been noted to inflict some damage.[3] Woodpeckers have been observed poking holes in the stems, which injures the plants.[4] Most of the remaining populations are within the bounds of a state park, so their habitat is safe from development.[3]