Mexican ball moss is not a true moss. Like its close relative, Spanish moss, it is a member of the pineapple family (Bromeliaceae).
These spherical masses can grow to the size of a soccer ball. Most of the increase in size of the sphere is from the development and growth of pups, or vegetative offsets, as each individual plant is quite small (perhaps 15cm (6 in.) tall). Considered unsightly by some, Mexican ball moss is also sometimes wrongly thought to be parasitic and therefore damaging to the supporting plant. It is readily apparent by its success in growing on power lines and fence wires that it does not need a host plant in order to prosper; any suitable branch-like support may work, although there are indeed habitat preferences (see: Habitat preference of the epiphyte Tillandsia recurvata (Bromeliaceae) in a semi-desert environment in Central Mexico by Bernal et al. in Canadian Journal of Botany, 2005, 83(10): 1238-1247).
The native range of Tillandsia recurvata spans the warmer areas of the Americas on either side of the equator, reaching as far south as northern Argentina and Chile, and as far north as southeastern Arizona in the USA.
The plants in today’s photograph are in fruit–one of the slender capsules near the top of the frame has started to dehisce (open). The evidence to-date points to dispersal of the seeds by wind instead of birds or other animals.