Cactoideae
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The Cactoideae are the largest subfamily of the cactus family (Cactaceae). They combine tiny, only one centimeter large and columnar cacti up to 20 meters high.
description
The Cactoideae are perennial , succulent plants that grow individually or in large groups and usually form shrubs or sometimes trees . Many species lignify somewhat with age. Most species grow terrestrially, but there are also some epiphytes . The roots are fibrous and then sometimes spread wide and flat under the surface of the earth, tap roots or sometimes succulent turnips , which can be more voluminous than the above-ground shoots. The rungs are ribbed, sometimes flattened into platycladia , or the ribs are partially or completely dissolved into spiraling warts. They are green and have taken on the task of photosynthesis . The leaves are almost always completely reduced or transformed into thorns standing on areoles . In the few exceptions ( Corryocactus brevistylus , Matucana aureiflora , Rhipsalis lumbricoides ) the leaves are tiny, scaly and quickly become obsolete. The thorns are varied (round or flattened, straight or hook-shaped), but a distinction is often made between marginal and differently shaped central spines on an areole. Glochids are absent.
The sessile flowers appear mostly singly, sometimes in small groups from the areoles, the axillae or between these grooves. They are almost always hermaphroditic and mostly radial symmetry , sometimes zygomorphic . Depending on how they adapt to the pollinators, they open during the day or at night. The flower tubes are between 0.2 and 15 (rarely up to 30) cm long. The five to over 50 bracts have a different shape; they change from outside to inside from bract-like to corolla-like shapes. The flowers contain many (50 to over 1500) stamens . Three to many (more than 100) carpels have become an under constant ovary grown. Each flower contains only a stylus with a number of scars according to the number of carpels. The pollination is done rarely by the wind ( Anemogamie ), mostly by animals ( Zoogamie ), while the pollinator (depending on the taxon) is very large: insects ( Entomogamie ), birds ( ornithophily ) or bats ( Chiropterophilie ).
The berries are at maturity either stained striking and then usually fleshy or inconspicuously and then dehydration. They contain from one to over 3000 seeds that are 0.3 to 5 mm in diameter, are yellowish, reddish, brown or black and have no hard seed coat.
The main differences to distinguish it from the other subfamilies are
- missing glochids,
- missing seed coat,
- missing or at least extremely reduced leaves.
Systematics
The subfamily Cactoideae is divided into nine tribes and contains about 100 genera with 1500 species:
- Tribe Browningieae Buxb.
- Tribus Cacteae Rchb.
- Tribe Calymmantheae R.S. Wallace
- Tribus Cereeae Salm-Dyck
- Tribe Hylocereeae Buxb.
- Tribe Notocacteae Buxb.
- Tribus Pachycereeae Buxb.
- Tribe Rhipsalideae DC.
- Tribe Trichocereeae Buxb.
Synonyms are Blossfeldioideae Crozier , 2004 and Rhipsalidoideae Burnett , 1835.
literature
- Edward F. Anderson : The Cactus Family . Timber Press: Portland (Oregon), 2001, ISBN 0-88192-498-9
