Calymmanthium
| Calymmanthium | |
|---|---|
| File:Calymmanthium substerile.jpg | |
| Kingdom | Plantae |
| Family | Cactaceae |
| Subfamily | Cactoideae |
| Tribe | Lymanbensonieae |
| SubTribe | |
| Genus | Calymmanthium |
| Species | |
| Notes | Taxonomy follows Joël Lodé (2015) and Korotkova (2011). |
Etymology
The name Calymmanthium means "Flower enveloped with a hood". This refers to the genus's most distinctive feature: the flowers initially resemble a new stem segment and must tear through the pericarp to emerge as they develop.
Description
Calymmanthium is a monotypic genus of shrubby to treelike cacti that branch profusely. The stems are angular, segmented, and feature distinct notches with well-defined areoles bearing stiff, needle-like (aciculate) spines.
The reproductive biology of this genus is unique. The flowers are self-sterile and nocturnal (though they begin as tubular during the day and become bell-shaped at night). They are pollinated by bats. A strange characteristic is that the floral remains persist and form a fruit-like structure even if pollination does not occur, though in such cases, the "fruit" remains sterile. The true fruits are slightly angled and indehiscent. The seeds are ovoid, black, and coarsely tuberculate.
Habitat
The genus is endemic to northeastern Peru, where it grows at altitudes between 950 m and 1800 m. It is typically found in thickets and among shrubs along riverbanks, preferring stony soils.
Distribution
- Peru (Amazonas, Cajamarca)
Species
Currently, the genus is considered monospecific (containing only one species):
- Calymmanthium substerile (syn. C. subfertile)
Notes
- Molecular studies (Wallace 1995, Applequist & Wallace 2002) have shown that Calymmanthium is a very ancient lineage with no close affinities to other cereoid cacti. It was previously suggested for its own tribe, Calymmantheae.
- Following the work of Korotkova (2011), it is now placed in the tribe Lymanbensonieae, alongside the genus Lymanbensonia.
- While molecular data once suggested a link to Copiapoa, the extreme morphological differences led researchers to keep them separate, leaving their exact relationship unresolved.
- It is considered one of the most primitive members of the subfamily Cactoideae.
