All Cactaceae are native to the New World. Only Rhipsalis baccifera has been
established in the Old World tropics long enough to have discrete varieties
there.

Pereskia is the only non-succulent genus in the Cactaceae. They are woody
broad leafed shrubs to trees.

The order Cactales is no longer recognized. Cactaceae are now included in
the Caryophyllales.

The family Cactaceae is best distinguished in the order by the floral
bracts, sepaloid and petaloid tepals being spirally arranged rather than in
separate whorls and intergrading into one another. Also Cactaceae have
areoles (axillary buds filled with hairs instead of scales) but they are not
unique to the family. Areoles are also found in the Portulacaceae and
Didiereaceae.


"S. M. Henning" wrote in message
news
(Geraldine Yellowhair) wrote:

what is a cactus?

Any plant of the order {Cactac[ae]}, as the prickly pear and
the night-blooming cereus. See {Cereus}. They usually have
leafless stems and branches, often beset with clustered
thorns, and are mostly natives of the warmer parts of
America.

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