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.
Basis for the genus
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).[1]
Characteristics
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.
Species
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.
Tulista maxima
Previously known as Haworthia maxima/pumila, 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.
Tulista marginata
Previously known as Haworthia marginata, this species occurs from the range of T.maxima 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.
Tulista minima
Previously known as Haworthia minima, this species occurs to the south of the range of T.marginata. Here it tends to occur in renosterveld vegetation, often near the coast.
It once again is more densely covered with tubercles, and sometimes offsets.
Tulista kingiana
Previously known as Haworthia kingiana, it is the rarest and furthest east of the four species. It occurs in the vicinity of Mossel Bay.
It has a lighter green colour and often has both margins, keels and tubercles. It tends to offset, much like T.minima, and it could be considered an extreme variety of this species.
Gallery
Some of the many varieties of the four species in this genus:
T. maxima
T. maxima.jpg)
T. maxima
T. maxima- T. marginata
T. marginata
T. marginata
T. marginata
T. minima
T. kingiana
References
- ↑ Manning, John; Boatwright, James S.; Daru, Barnabas H.; Maurin, Olivier; van der Bank, Michelle. A Molecular Phylogeny and Generic Classification of Asphodelaceae subfamily Alooideae: A Final Resolution of the Prickly Issue of Polyphyly in the Alooids? Systematic Botany, Volume 39, Number 1, March 2014, pp. 55-74
External links
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