CACTACEAE - Cactus Family
Succulent, fleshy, spiny herbs, rarely succulent stems with
alternate, simple leaves
Leaves - usually scalelike, much reduced
Areole - modified axilllary bud
or a short branch or node with leaves or bud-scales modified into
spines
Flowers are axillary
at nodes
Sepals and petals are not clearly differentiated and are referred
to as tepals
Pollinated by bees, hummingbirds, bats, hawk moths
30 to 200 genera, 2000 species, depending on treatment (splitters vs.
lumpers), almost entirely limited to New World. The taxonomy of this
family is rather confused due in a large extent to the large number
of amateurs attracted to it.
The Cactaceae is divided into three subfamilies:
I. Pereskioideae - leaves broad, no glochids.
II. Opuntioideae - leaves terete, glochids present, stem often
flattened.
III. Cactoideae - leaves absent or very small, no glochids.
Phylogenetic relationships were unclear until betalains were
found in cacti
Cacti have evolved their characteristic habit in response to hot, dry
climate; Pereskia is
thought to be primitive since it has leaves
Economic uses - ornamentals, fruits and pads of prickly pear are
edible (Texas alfalfa), hallucinogenic plants (peyote)
Medicinal uses - Opuntia pads placed on wounds, fruit juice on
warts, tea for a variety of ailments.
Diagnostic characters - leaves reduced, stems with areoles and
spines, flower parts many and sepals and petals undifferentiated,
ovary inferior.
IMAGE GALLERY
FLOWERING
PLANT GATEWAY
