The Cactoideae are the largest subfamily of the cactus family ( Cactaceae ). They combine tiny, only an inch wide and columnar up to 20 meters tall cactus.
The Cactoideae are perennial, succulent plants that grow singly or in large groups and usually or sometimes form Shrubs Trees. Many species of woody aged somewhat. Most species grow terrestrial, but there are also some epiphytes. The roots are fibrous and then sometimes spread wide and flat below the earth's surface, tap roots or sometimes succulent beets, which may be more voluminous than the above-ground shoots. The shoots are ribbed, sometimes to Platykladien flattened, or the ribs are partly or completely dissolved in a spiral extending warts. They are green and have taken on the task of photosynthesis. The leaves are almost always completely reduced or converted to standing on areoles thorns. The few exceptions ( Corryocactus brevistylus, Matucana aureiflora, rhipsalis lumbricoides ), the leaves are tiny, scale-like and quickly obsolete. The thorns are, however multiform (round or flattened, straight or hook-shaped ), often is to distinguish between a areola border and differently shaped central spines. Glochids are not available.
The sessile flowers usually appear singly, sometimes in small groups from the areoles, axillae or lying between these furrows. They are almost always hermaphroditic and mostly radial symmetry, sometimes zygomorphic. Depending on the adjustment to the pollinators they open during the day or at night. The flower tubes are 0.2 to 15 (rarely to 30) cm long. The five to 50 bracts have a different shape; they change from outside to inside of bract similar to kronblattähnlichen forms. The flowers contain many ( 50 to over 1500) stamens. Three to many ( up to 100 ) carpels are fused to an inferior ovary. Each flower contains only a stylus with a number of scars according to the number of carpels. Pollination is rare due to the wind ( Anemogamie ), usually by animals ( Zoogamie ), while the pollinator (depending on the taxon ) is very large: insects ( Entomogamie ), birds ( Ornithophilie ) or bats ( Chiropterophilie ).
The berries are either strikingly colored at maturity and then usually fleshy or inconspicuously and then dehydration. They contain one to about 3000 seeds, which have 0.3 to 5 mm in diameter, are yellowish, reddish, brown or black and do not have a hard seed coat.
The main differences to differentiate to the other subfamilies are
- Missing glochids,
- Lack of seed coat,
- Missing, or at least extremely reduced leaves.
The subfamily Cactoideae is divided into nine tribes, and contains about 100 genera and 1500 species:
- Tribus Browningieae Buxb.
- Tribus Cacteae
- Tribus Calymmantheae R.S.Wallace
- Tribus Cereeae Salm- Dyck
- Tribus Hylocereeae Buxb.
- Tribus Notocacteae Buxb.
- Tribus Pachycereeae Buxb.
- Tribus Rhipsalideae DC.
- Tribus Trichocereeae Buxb.
Synonyms are Blossfeldioideae Crozier, 2004 and Rhipsalidoideae Burnett, 1835.