Tulista

''Tulista'' is a small genus of succulent plants endemic to South Africa. They were formerly included within the genus ''Haworthia''.

Characteristics

The genus is characterised by a large size (relative to other haworthias), by their stemless rosette growth form, by the yellow exudate in their non-fibrous leaves, and by their distinctive flowers with robust peduncles.

Taxonomy

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 phylogenetic studies have confirmed this division, and shown that ''Haworthia'' actually comprises three clades that are only distantly related. Based on phylogenetic evidence, in 2013, Gordon Rowley revived the genus ''Tulista'', first erected by Constantine Samuel Rafinesque in 1840, but long consigned to synonymy with ''Haworthia''. However, Rowley adopted a very broad concept of ''Tulista'', in which as well as ''Haworthia'' subgenus ''Robustipedunculares'', the genus included '' Astroloba'' and ''Aloe aristata'' (now '' Aristaloe aristata''), among other taxa. Later in 2013, this broad concept was rejected by Manning et al. later, and ''Tulista'' re-circumscribed to consist of four species, a decision supported by Gildenhuys and Klopper in 2016. Rowley has subsequently defended his original approach to the genus, though it is no longer widely accepted. The same phylogenetic studies suggested that the closest relatives of ''Tulista'' were the genera '' Astroloba'' and ''Gonialoe''.

Species

In 2014, Manning et al. recognized four species in the genus ''Tulista'', although , the World Checklist of Selected Plant Families accepts only three of them. All four species are highly variable, each with many different forms.




*'' Tulista kingiana'' (Poelln.) Gideon F.Sm. & Molteno
::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 yellow-green colour, smooth glossy tubercles, and it sometimes has margins and keels. There are compact rounded forms, and thin elongated forms. Some populations also offset.
*'' Tulista marginata'' (Lam.) G.D.Rowley
::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 it usually has clear margins and a keel on its leaves. It is also extremely variable in its forms and it is highly prized as an ornamental. It does not usually offset.
*'' Tulista minor'' (Aiton) Gideon F.Sm. & Molteno
::Previously known as ''Haworthia minima'' or ''Haworthia minor'', 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 is very densely covered with tubercles and it usually has a blue-green colour. There are compact rounded forms, and thin elongated forms. Some populations offset.
*'' Tulista pumila'' (L.) G.D.Rowley
::Previously known as ''Haworthia pumila/maxima/margaritifera'', this is the far western species, occurring in the Robertson Karoo vegetation in the Western Cape, South Africa. It is the largest species. It usually has a darker colour and raised tubercles on its leaves. It does not usually offset.

Gallery

Some of the many varieties of the four species in this genus:

File:Haworthia maxima in cultivation.jpg, ''T. pumila''
File:Haworthia Maxima (6890633155).jpg, ''T. pumila''
File:Z Sparsa hawortha pumila 4.jpg, ''T. pumila''
File:Haworthia marginata - Tulista Heidelberg RSA 99.jpg, ''T. marginata''
File:Tulista marginata - drew variety in cultivation 5.jpg, ''T. marginata''
File:Haworthia marginata Tulista in habitat - Western Cape Acilliers 5.jpg, ''T. marginata''
File:Haworthia minima MBB 3.jpg, ''T. minor''
File:Tulista minima - brandrivier opalina form 2.jpg, ''T. minor''
File:Haworthia minima MBB 7.jpg, ''T. minor''
File:Tulista kingiana 4 - compact form.jpg, ''T. kingiana''
File:Tulista kingiana at Moerasrivier after fire 1.jpg, ''T. kingiana''
File:Tulista kingiana 1 - compact form.jpg, ''T. kingiana''

Notes

References

External links

{{Taxonbar, from=Q20720103

Flora of the Cape Provinces
Renosterveld
Asphodelaceae genera
Taxa named by Constantine Samuel Rafinesque