Tulista
| Tulista | |
|---|---|
 |
|
| Tulista marginata | |
| Scientific classification | |
| Kingdom: | Plantae |
| Clade: | Angiosperms |
| Clade: | Monocots |
| Order: | Asparagales |
| Family: | Asphodelaceae |
| Subfamily: | Asphodeloideae |
| Genus: |
Tulista Raf. |
| Synonyms | |
Tulista is a small genus of succulent plants endemic to South Africa. They were formerly included within the related genus Haworthia.
The genus Haworthia was long considered problematic, and suspected of being polyphyletic. It was accordingly divided into three different subgenera: Haworthia (the soft, green, leafy, and often retuse species); Hexangulares (the harder, often tubercled species); Robustipedunculares (the four largest, most robust species). Several recent phylogenetic studies have confirmed this division, and shown that Haworthia actually comprises three relatively unrelated genera. The three subgenera were therefore elevated into being distinct genera.
The species of subgenus Robustipedunculares were accordingly given their own genus: "Tulista".
The same studies suggested that the closest relatives of this proposed genus were the related genus Astroloba and Gonialoe (Aloe variegata, Aloe sladeniana, Aloe dinteri).
The four species of this genus are characterised by their large size (relative to other Haworthias) and by their distinctive flowers with their inflated robust peduncles.
The Tulista entity is divided into four species, in recognition of the four traditionally recognised species of this group.
All four species are highly variable, each with many different forms. There also do not seem to be firm boundaries between the species; at the boundaries between species there exists a gradual transition from one species to the other.
Previously known as Haworthia pumila/maxima, this is the far western species, occurring in the Robertson Karoo vegetation in the Western Cape, South Africa.
It is the largest species, and usually exhibits raised tubercles on its leaves.
Previously known as Haworthia marginata, this species occurs from the range of T.pumila eastwards, as far as Riversdale.
The second largest species, it has fewer or no tubercles, and often has strong margins and keel on its leaves. It is also extremely variable in its forms, and is highly prized as an ornamental.
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Wikipedia