If aloes are the bold extroverts of the alooid world, haworthias are the jewels you have to look closely to appreciate. These miniature succulents — rarely exceeding fifteen centimetres in diameter — are among the most collected plants on Earth. A single Haworthia truncata, its flat-topped leaves forming a row of living windows, can sell for hundreds of dollars. A well-grown Haworthia cooperi, its translucent leaf tips glowing like green glass in backlighting, is as beautiful as any gemstone. And a Haworthiopsis attenuata — the ubiquitous “zebra plant” — sits on millions of windowsills worldwide, quietly surviving conditions that would kill most other succulents.
What most growers do not realise is that the plant they call “Haworthia” may no longer belong to that genus at all. Molecular phylogenetic studies have shown that the old genus Haworthia was not a natural group — it contained three distinct evolutionary lineages that are only distantly related. In 2013–2014, the genus was split into three: Haworthia sensu stricto (the soft-leaved, windowed species), Haworthiopsis (the hard-leaved, tuberculate species — including the famous zebra plant) and Tulista (the large, robust species). This reclassification has caused endless confusion in nurseries and collections worldwide — but it reflects genuine evolutionary reality, and understanding it makes growing these plants easier.
This page is the reference for the haworthioid group on our site. It covers taxonomy, the three-way split, cultivation, species selection and the resources that every haworthia grower needs.
Taxonomy and classification
A brief history
The genus Haworthia was established by Henri Auguste Duval in 1809, separating a group of small-leaved succulent plants from the large genus Aloe on the basis of their distinctive, smaller, two-lipped (bilabiate) flowers. The genus was named after the English botanist Adrian Hardy Haworth (1767–1833). For over two centuries, Haworthia was broadly circumscribed — any small, rosette-forming alooid with bilabiate flowers was placed here, from the soft, translucent-leaved species of the Western Cape to the hard, tuberculate species of the Eastern Cape and the large, robust species now placed in Tulista.
The taxonomy has been described, with good reason, as “one of the most difficult problems in succulent plant systematics.” The species are extremely variable — a single species can look completely different depending on its growing conditions, its age and its geographic origin. Juvenile plants often look nothing like adults. Natural hybrids form wherever species ranges overlap. And the sheer number of described names — over five hundred — relative to the number of accepted species (~150 in Haworthia s.s. alone) reflects decades of taxonomic confusion.
The three-way split: Haworthia, Haworthiopsis, Tulista
In 1971, M.B. Bayer divided Haworthia into three subgenera based on morphology: subgenus Haworthia (soft-leaved, often windowed), subgenus Hexangulares (hard-leaved, often tuberculate) and subgenus Robustipedunculatae (large, robust). Multiple phylogenetic studies from 2010 onwards confirmed that these three subgenera were not closely related — they belonged to different branches of the alooid family tree. The key findings:
Subgenus Haworthia (the soft-leaved species) is positioned in a polytomy with Kumara (the fan aloes) and Aloiampelos (the scrambling aloes) — closer to these genera than to the other two haworthia subgenera.
Subgenus Hexangulares (the hard-leaved species) is sister to Gasteria — more closely related to gasterias than to the soft-leaved haworthias.
Subgenus Robustipedunculatae (the large, robust species) forms a clade with Astroloba, Aristaloe and Gonialoe — closer to these genera than to either of the other haworthia subgenera.
In 2013, Gordon Rowley formalised this split by erecting the genus Haworthiopsis for subgenus Hexangulares and reviving Tulista (originally described by Rafinesque in 1840) for subgenus Robustipedunculatae. Manning et al. (2014) refined the circumscription. Woudstra et al. (2025) confirmed the monophyly of all three genera using nuclear phylogenomics.
The result: what was one genus is now three:
1. Haworthia sensu stricto — approximately 38 species (131 taxa including varieties) of soft-leaved, often windowed succulents. The “true haworthias.” Endemic to South Africa (Western, Eastern and Northern Cape). These are the species that collectors prize — Haworthia truncata, Haworthia cooperi, Haworthia retusa, Haworthia cymbiformis, Haworthia maughanii, Haworthia magnifica, Haworthia mirabilis and many more.
2. Haworthiopsis — approximately eighteen species of hard-leaved, often tuberculate succulents. The “zebra haworthias.” The most commercially important group — Haworthiopsis attenuata (the zebra plant) and Haworthiopsis fasciata are among the most widely sold succulents on Earth. Other notable species include Haworthiopsis limifolia (the file-leaved haworthia), Haworthiopsis reinwardtii, Haworthiopsis coarctata and Haworthiopsis glauca. Divided into five sections: Attenuatae, Haworthiopsis, Limifoliae, Koelmaniorum and Tessellatae.
3. Tulista — four species of large, robust haworthioids: Tulista pumila (formerly Haworthia pumila or H. maxima or H. margaritifera), Tulista marginata (formerly Haworthia marginata), Tulista minor (formerly Haworthia minima) and Tulista kingiana (formerly Haworthia kingiana). All endemic to the Western Cape, all highly variable, all densely covered in white tubercles. They are the largest of the former haworthias — rosettes can exceed twenty centimetres — and their flowers have distinctively robust peduncles.
What this means for growers
The split changes names but not culture. Your “Haworthia attenuata” is the same plant as Haworthiopsis attenuata — it just has a new genus name. Nurseries are very slow to adopt the changes, and you will encounter old names for years to come. On our site, we use the currently accepted names following POWO (Plants of the World Online), with former names noted as synonyms.
However, the split does reflect real biological differences that matter for cultivation. The soft-leaved Haworthia species are generally more shade-demanding, more moisture-sensitive and more cold-tender than the hard-leaved Haworthiopsis species. Understanding which group your plant belongs to helps you grow it better.
Distribution
All three genera are endemic to southern Africa, with the overwhelming majority of species found in South Africa.
Haworthia sensu stricto: endemic to South Africa — Northern, Western and Eastern Cape Provinces, with one species extending into the southern Free State. The Western Cape hosts 97 taxa (84 endemic); the Eastern Cape 42 taxa (33 endemic). The centre of diversity lies in the winter-rainfall and year-round-rainfall zones of the southwestern and southern Cape.
Haworthiopsis: wider distribution across South Africa, with some species extending into Mozambique, Eswatini and possibly Namibia. Haworthiopsis limifolia has a notably eastern distribution (KwaZulu-Natal, Mpumalanga, Eswatini).
Tulista: restricted to the Western Cape Province of South Africa.
In habitat, haworthioids grow in sheltered positions — under bushes, between rocks, in cliff crevices, partially buried in the soil with only the leaf tips exposed. Many species are cryptic — their colouration matches the surrounding soil and stones, making them nearly invisible. This cryptic habit protects them from herbivores and excessive sun.
Morphology
Haworthia sensu stricto — the soft-leaved haworthias
Small rosettes, typically three to ten centimetres in diameter. Leaves are soft, fleshy, often translucent — many species have “windows” (transparent or semi-transparent areas at the leaf tips) that allow light to penetrate to the photosynthetic tissue inside, even when the plant is partially buried. Leaf shapes range from triangular to rounded, retuse (flat-topped), truncate (cut off flat) and cylindrical. Colours include green, grey-green, brownish and, in stress conditions, red or purple. Many species have prominent veining visible through the translucent leaf surface.
Flowers are small, bilabiate (two-lipped), white to greyish-white, on slender scapes. Pollinated by proboscis flies and bees.
Haworthiopsis — the hard-leaved haworthias
Small to medium rosettes or columnar plants. Leaves are firm, hard, with a thicker epidermis than Haworthia. Many species have prominent white tubercles (raised bumps) arranged in bands or scattered across the leaf surface — the “zebra stripes” that make H. attenuata and H. fasciata so recognisable. Some species are columnar rather than rosette-forming (H. reinwardtii, H. coarctata). Flowers are small, whitish, with straight styles (unlike the curved styles of Haworthia).
Tulista — the robust haworthioids
The largest of the former haworthias — rosettes to twenty centimetres or more. Leaves are thick, hard, heavily covered in dense white tubercles. Flowers are borne on robust, thick peduncles (hence the subgenus name Robustipedunculatae). All four species are highly variable — each encompasses numerous forms that differ in leaf shape, tubercle density and size.
Cultivation
Haworthioids are among the easiest and most rewarding succulents for indoor and container culture. Their small size, shade tolerance and drought resistance make them ideal for windowsills, shelves, offices and any bright indoor space.
Light: bright indirect light — the golden rule for all three genera. Most haworthioids do not want full sun, especially hot afternoon sun. In habitat, they grow in the shade of rocks and bushes, often partially buried. Direct sunlight can scorch the leaves — particularly the soft, translucent leaves of Haworthia sensu stricto. Haworthiopsis species are slightly more sun-tolerant (their harder leaves have a thicker epidermis), but even these perform best in bright shade or morning sun only. Tulista tolerates more light than the other two genera but still prefers some afternoon shade in hot climates.
Substrate: well-drained, gritty, slightly acidic. A mix of 50 % mineral material (pumice, perlite, coarse sand) and 50 % quality potting compost or coco coir. Standard cactus and succulent mix is acceptable. The substrate must drain quickly, but haworthioids are more tolerant of slightly moisture-retentive mixes than desert aloes — they come from regions with year-round rainfall.
Watering: moderate. Water when the substrate is dry to the touch — typically every one to two weeks during the growing season (spring and autumn for most species). Reduce in summer (many species go semi-dormant in extreme heat) and in winter. Never let the roots sit in water. Haworthioids are drought-tolerant but not as xerophytic as agaves or desert cacti — they appreciate more regular moisture than many growers expect.
Temperature: most species are comfortable between 5 and 30 °C. Frost tolerance is limited — most are damaged below -2 °C and killed below -5 °C. A few Haworthiopsis species and Tulista tolerate brief frost to -5 °C in dry soil. In frost-prone climates, grow indoors or in a cool greenhouse year-round.
Growing season: spring and autumn for most species. Many haworthioids slow down or go semi-dormant during the peak of summer heat and the depth of winter. The bimodal growing pattern — active in spring, resting in summer, active again in autumn, resting in winter — reflects the rainfall patterns of the Western and Eastern Cape.
Growing the three genera: key differences
Haworthia sensu stricto: the most shade-demanding. The translucent leaf windows are an adaptation to growing partially buried — they let light in while the rest of the plant stays protected. In cultivation, too much light bleaches or reddens the leaves (stress colouration). Too little light causes etiolation. The sweet spot is bright indirect light, or morning sun with afternoon shade. Water regularly but never waterlog — the soft leaves rot easily if the crown stays wet.
Haworthiopsis: the most tolerant and forgiving. Harder leaves resist both sun and drought better than Haworthia. H. attenuata and H. fasciata are nearly indestructible — they survive neglect, poor light, irregular watering and dry air better than almost any other succulent. The harder epidermis provides a margin of error that the soft-leaved species do not have.
Tulista: more light-tolerant than the other two genera. Can take morning to midday sun. Watering and drainage requirements are standard. The large size (for a haworthioid) means they need bigger pots and can make an impact as standalone specimens rather than just parts of a collection.
Propagation
From offsets: many haworthioids sucker prolifically, producing basal offsets that can be detached and potted individually. Some species (Haworthia retusa, Haworthia maughanii, many Haworthiopsis) are prolific offsetters. Others (Haworthia truncata, most Tulista) rarely offset and must be propagated by seed or leaf cuttings.
From leaf cuttings: possible for many species, particularly Haworthiopsis. Detach a healthy leaf, allow it to dry for a few days, lay it on moist substrate. A tiny plantlet will eventually emerge from the base. Success rates vary by species.
From seed: germination is rapid at 20–25 °C — often within one to two weeks. Seedlings are tiny and slow-growing but reach flowering size in two to four years for most species. Seed-raised plants are genetically diverse — important for conservation and for producing novel forms. Note: haworthioids hybridise extremely easily. If multiple species are flowering simultaneously, seeds may be hybrids unless pollination is controlled.
Pests and diseases
Mealybugs: the most common pest, especially indoors and in collections. White cottony masses at leaf bases and in root zones. Root mealybugs are particularly insidious — they feed underground and are invisible until the plant begins to decline. Treatment: isopropyl alcohol for aerial mealybugs, systemic insecticide (where available) for root mealybugs.
Root rot: from overwatering or poorly drained substrate. The soft-leaved Haworthia species are particularly vulnerable. Prevention: proper substrate, correct watering rhythm, drainage holes.
Sunburn: brown or white marks on leaves from excessive direct sun. Move to a shadier position.
Species list
Haworthia sensu stricto — the soft-leaved haworthias (~38 species, ~131 taxa)
The most species-rich and taxonomically complex of the three genera. Species concepts are debated — M.B. Bayer’s 2009 revision recognises fewer, broader species, while other authors (notably Hayashi and Breuer) recognise many more, narrower taxa. The list below follows Bayer’s broad species concept with selected varieties.
The retuse / truncate group — species with flattened or windowed leaf tips. The crown jewels of the genus.
Haworthia truncata Schönl. — Western Cape (Little Karoo). The most iconic haworthia. Leaves arranged in two ranks (distichous), each leaf flat-topped as if cut with a knife. The truncated surface is a window — translucent, letting light penetrate to buried tissue. Highly sought-after; rare forms and cultivars command premium prices. Does not offset easily — propagation mainly by seed.
Haworthia maughanii Poelln. — Eastern Cape (near Humansdorp). Cylindrical leaves with flat, circular, translucent windows at the tips. In habitat, the plant grows buried with only the window tips at soil level. One of the most extraordinary succulents in the world. Slow-growing, offsets freely in cultivation.
Haworthia retusa (L.) Duval — Western and Eastern Cape. Triangular, retuse leaves with translucent windows. Variable — many forms exist. One of the easier windowed species to grow.
Haworthia emelyae Poelln. — Western and Eastern Cape. Including the highly prized var. comptoniana (Poelln.) M.B. Bayer, with large, pronounced windows and intricate reticulate patterning visible through the translucent leaf surface. One of the most beautiful haworthias.
Haworthia mutica Haw. — Western Cape (Swellendam area). Rounded, retuse leaves with subtle windows. Compact, easy to grow.
Haworthia magnifica Poelln. — Western Cape (near Riversdale). Pronounced windows, variable forms. Several varieties, including var. splendens (deeply coloured, highly ornamental) and var. atrofusca (dark brown-purple leaves).
Haworthia bayeri J.D.Venter & S.A.Hammer — Western Cape. Named after M.B. Bayer. Retuse, windowed. A collector’s species.
The mirabilis group — species with pointed, often keeled leaves, sometimes with translucent areas.
Haworthia mirabilis (Haw.) Haw. — Western Cape. Extremely variable — over a dozen varieties are recognised, including var. mundula, var. paradoxa, var. triebneriana and others. Some forms are highly translucent; others are opaque and dark. A “species complex” that illustrates the taxonomic challenges of the genus.
Haworthia maraisii Poelln. — Western Cape. Small, with tuberculate, pointed leaves. Several varieties.
The cooperi / cymbiformis group — soft, pale green, often prolific offsetters.
Haworthia cooperi Baker — Eastern Cape (Baviaanskloof area). One of the most beautiful haworthias: translucent, pale green, globe-shaped leaves that glow when backlit. Multiple varieties, including var. truncata (flattened, very translucent), var. pilifera (with fine bristles at the leaf tips) and var. dielsiana. Prolific offsetter — forms dense clumps.
Haworthia cymbiformis (Haw.) Duval — Eastern Cape (widespread, from Port Elizabeth to Makhanda). The “boat-shaped” haworthia — pale green, translucent, very easy to grow. Offsets freely. One of the best haworthias for beginners.
Haworthia decipiens Poelln. — Eastern Cape. Including the notable var. xiphiophylla (sword-leaved form). Soft, green.
Other notable Haworthia species
Haworthia herbacea (Mill.) Stearn — Western Cape. Compact, dark green, firm leaves with translucent tips. Very variable.
Haworthia mucronata Haw. — Western and Eastern Cape. Pointed leaves with a terminal bristle (mucro). Several varieties.
Haworthia lockwoodii Archibald — Western Cape. A distinctive species with opaque, hard leaves that dry back from the tips — in habitat, the dried tips protect the living tissue beneath from sun and drought. A curiosity.
Haworthia angustifolia Haw. — Southern Cape. Narrow, grass-like leaves. Easy to grow, offsets freely.
Haworthia nortieri G.G. Sm. — Western Cape (Citrusdal area). A distinctive species from winter-rainfall areas. Compact, with darkly coloured, opaque leaves.
Haworthia arachnoidea (L.) Duval — Western Cape. Covered in fine, white, cobweb-like filaments — the “spider web haworthia.” Several varieties. Distinctive and attractive.
Haworthia bolusii Baker — Eastern Cape, Free State. Covered in long, white, bristle-like leaf tips that form a dense tuft — the “hairy haworthia.” Very distinctive. Hardy — tolerates light frost.
Haworthiopsis — the hard-leaved haworthias (~18 species)
Divided into five sections (following Gildenhuys & Klopper 2016):
Section Attenuatae
Haworthiopsis attenuata (Haw.) G.D. Rowley — Eastern Cape (widespread). The zebra plant. The most widely sold haworthia in the world — millions are produced annually. Dark green, triangular leaves with prominent white tubercle bands on the outer surface. Extremely easy to grow, tolerates neglect, low light and irregular watering. Multiple cultivated forms, including ‘Super White’ (very dense white banding) and ‘Radula’ (fine, sandpaper-like tubercles). The gateway plant for succulent collecting.
Section Haworthiopsis
Haworthiopsis fasciata (Willd.) G.D. Rowley — Eastern Cape. Very similar to H. attenuata but with smooth inner leaf surfaces (no tubercles inside). Often confused with H. attenuata in the trade.
Haworthiopsis reinwardtii (Salm-Dyck) G.D. Rowley — Eastern Cape. A columnar species — tall, spiralling stems covered in small, overlapping, tuberculate leaves. Can reach thirty centimetres tall. Offsets from the base to form clusters.
Haworthiopsis coarctata (Haw.) G.D. Rowley — Eastern Cape. Similar to H. reinwardtii but with leaves pressed more tightly to the stem. Columnar, clustering.
Haworthiopsis glauca (Baker) G.D. Rowley — Eastern Cape. Blue-grey, smooth leaves without prominent tubercles. Columnar to spiralling. A distinctive, elegant species.
Haworthiopsis longiana (Poelln.) G.D. Rowley — Eastern Cape. Long, narrow, dark green leaves with fine white margins.
Section Limifoliae
Haworthiopsis limifolia (Marloth) G.D. Rowley — Mpumalanga, KwaZulu-Natal, Eswatini. The file-leaved haworthia. Broad rosettes of dark green leaves with distinctive transverse ridges that feel like a file. The most easterly of all haworthioids. Several varieties, including var. ubomboensis (from the Ubombo Mountains). Popular and easy to grow.
Section Koelmaniorum
Haworthiopsis koelmaniorum (Oberm. & D.S.Hardy) Boatwr. & J.C.Manning — Mpumalanga. A taxonomically enigmatic species — molecular studies place it uncertainly between Haworthiopsis and Tulista. Distinctive: rough, dark, warty leaves. Rare in cultivation.
Section Tessellatae
Haworthiopsis tessellata (Haw.) G.D. Rowley — widespread across South Africa. The “tessellated haworthia” — brownish-green leaves with a distinctive mosaic pattern of raised lines on the upper surface. Very variable. Easy to grow, tolerates poor conditions.
Haworthiopsis venosa (Lam.) G.D. Rowley — Eastern Cape. Similar to H. tessellata but with more prominent venation. Including the former Haworthia woolleyi.
Haworthiopsis granulata (Marloth) G.D. Rowley — Western and Eastern Cape. Finely granulated leaf surface. Compact.
Tulista — the robust haworthioids (4 species)
Tulista pumila (L.) G.D. Rowley (syn. Haworthia pumila, H. maxima, H. margaritifera) — Western Cape (Robertson Karoo). The pearl plant. The largest haworthioid — rosettes to twenty centimetres or more. Densely covered in large, pearly white tubercles. Extremely variable — many named forms exist. Widely cultivated for centuries (it was among the first haworthioids brought to Europe).
Tulista marginata (Lam.) G.D. Rowley (syn. Haworthia marginata) — Western Cape (east of T. pumila‘s range, to Riversdale). Fewer tubercles than T. pumila, with clear margins and a keel on the leaves. Highly prized as an ornamental. Does not usually offset.
Tulista minor (Aiton) Gideon F. Sm. & Molteno (syn. Haworthia minima, Haworthia minor) — Western Cape (south of T. marginata‘s range, near the coast). Very densely covered in tubercles. Blue-green. Compact rounded and elongated forms exist.
Tulista kingiana (Poelln.) Gideon F. Sm. & Molteno (syn. Haworthia kingiana) — Eastern Cape (the most eastern of the four species). The rarest Tulista. Compact, densely tuberculate.
Choosing haworthioids for your collection
For beginners: Haworthiopsis attenuata (the zebra plant — nearly indestructible), Haworthia cymbiformis (soft, translucent, easy), Haworthiopsis fasciata (classic striped look), Haworthia cooperi (glowing windows, prolific offsetter).
For windowsill culture: Haworthia retusa, Haworthia cooperi, Haworthia cymbiformis, Haworthiopsis tessellata. These tolerate the lower light of a north or east-facing window.
For serious collectors: Haworthia truncata (the living window), Haworthia maughanii (cylindrical windows), Haworthia emelyae var. comptoniana (intricate reticulations), Haworthia magnifica var. splendens (deep colour).
For architectural impact: Tulista pumila (large, pearly, sculptural), Tulista marginata (elegantly keeled), Haworthiopsis reinwardtii (tall columnar spirals).
For unusual forms: Haworthia lockwoodii (dried-back leaf tips), Haworthia arachnoidea (cobweb filaments), Haworthia bolusii (hairy tufts), Haworthiopsis koelmaniorum (dark, warty, taxonomically enigmatic).
Hybridisation
Haworthioids hybridise with extraordinary ease — within and between genera. Haworthia × Haworthia, Haworthia × Haworthiopsis, Haworthiopsis × Gasteria (= ×Gasterhaworthia), Haworthiopsis × Aloe, Tulista × Astroloba — all have been produced. In Japan and South Korea, a massive commercial industry has developed around selected and hybridised haworthias — particularly Haworthia truncata and Haworthia maughanii cultivars — with individual named clones selling for thousands of dollars. The Japanese influence on haworthia horticulture is enormous: many of the cultivar names used worldwide are Japanese.
For collectors, the ease of hybridisation is both a blessing and a warning. Named cultivars from reputable sources are desirable. But any haworthia grown from open-pollinated seed should be assumed to be a potential hybrid unless pollination was carefully controlled.
Web resources
Plants of the World Online (POWO) — Kew Royal Botanic Gardens. The authoritative database for accepted names and synonymy. Essential for resolving the nomenclatural chaos that surrounds haworthias. powo.science.kew.org
Haworthia Updates. The website of M.B. Bayer, the foremost authority on Haworthia taxonomy. Contains decades of published articles, taxonomic revisions, field observations and photographs. The most important single resource on Haworthia systematics — indispensable for anyone serious about the genus. haworthiaupdates.org
The Haworthia Society. The international society dedicated to haworthias, gasterias and related genera. Publishes the journal Haworthiad (quarterly). The website includes species checklists, cultivation guides and a shop for specialist publications including Ingo Breuer’s taxonomic works. haworthia.org
PlantZAfrica — South African National Biodiversity Institute (SANBI). The genus page for Haworthia, written by Sean Gildenhuys, is an outstanding overview with distribution data, morphological descriptions and habitat photographs. pza.sanbi.org
Haworthia-Gasteria blogspot. A comprehensive identification aid with photographs from habitat and cultivation, created by Kuba — a passionate grower who has made multiple field trips to South Africa. Follows Bayer’s taxonomy with pragmatic adjustments. Excellent for identification. haworthia-gasteria.blogspot.com
Encyclopaedia of Succulents — Llifle. Cultivation notes and photographs for many haworthioid species. Quality varies. llifle.com
iNaturalist. Citizen-science observations of haworthias in habitat. Valuable for understanding natural variation and geographic distribution. inaturalist.org
Bibliography
Monographs and revisions
Bayer M.B. (1982). The New Haworthia Handbook. National Botanic Gardens of South Africa, Kirstenbosch. — The first modern comprehensive treatment. Established the three-subgenus framework (Haworthia, Hexangulares, Robustipedunculatae) that would later become the basis for the three-genus split.
Bayer M.B. (1999). Haworthia Revisited. Umdaus Press, Hatfield. — The revised and expanded monograph, with detailed species descriptions, distribution maps and photographs. The standard reference for Haworthia taxonomy until the 2009 update.
Bayer M.B. (2009). Haworthia Update. Vol. 1–5. Essays on Haworthia. Self-published/Hatfield. — The most recent comprehensive revision by Bayer, with further species reductions, field observations and taxonomic notes. The reference used for the species list on this page.
Breuer I. (2010). The World of Haworthias. Volumes 1–2. Self-published, Germany. — An alternative taxonomic treatment that recognises more species and infraspecific taxa than Bayer. Extensively illustrated. The reference preferred by many collectors, particularly those following the Japanese and Korean cultivar traditions.
Scott C.L. (1985). The Genus Haworthia: A Taxonomic Revision. Aloe Books, Johannesburg. — An earlier revision, now largely superseded but historically important.
Molecular phylogenetics and classification
Rowley G.D. (2013). Generic concepts in Alooideae. Part 7 — Haworthiopsis. Alsterworthia International, Special Issue 10. — The original description of the genus Haworthiopsis.
Manning J.C., Boatwright J.S., Daru B.H., Maurin O., Van der Bank M. (2014). A molecular phylogeny and generic classification of Asphodelaceae subfamily Alooideae. Systematic Botany, 39(1): 55–74. — The paper that refined the circumscription of Haworthia, Haworthiopsis and Tulista.
Gildenhuys S.D., Klopper R.R. (2016). A synoptic review of the genus Haworthiopsis. Bradleya, 34: 2–57. — The definitive revision of Haworthiopsis, with keys, descriptions and distribution maps for all accepted species.
Zonneveld B.J.M. (2015). Nuclear genome sizes of 343 accessions of wild-collected Haworthia (Asphodelaceae, Alooideae). Plant Systematics and Evolution, 301: 1405–1424. — Genome size data supporting the three-way split.
Woudstra Y., Grace O.M., Klopper R.R. et al. (2025). Nuclear phylogenomics reveals strong geographic patterns in the evolutionary history of Aloe and related genera (alooids). Annals of Botany. — Confirms the monophyly of Haworthia, Haworthiopsis and Tulista as separate genera.
Cultivation
Schulz R. (2009). Haworthia for the Collector. Published by the author. — A practical guide focused on cultivation, with advice on substrate, watering, light and propagation.
Sajeva M., Costanzo M. (2000). Succulents II: The New Illustrated Dictionary. Timber Press. — Includes cultivation notes for many haworthioid species.
Going further
The haworthioid group — Haworthia, Haworthiopsis and Tulista — is one of the most rewarding corners of the succulent world for collectors. Small enough to grow dozens on a single shelf, shade-tolerant enough to thrive indoors, infinitely variable and taxonomically fascinating, they reward close observation and patient cultivation. Whether you start with a single Haworthiopsis attenuata from a garden centre or pursue the rarest forms of Haworthia truncata, the journey is the same: a deepening appreciation for one of nature’s most exquisite miniature creations. Our site offers detailed species profiles, care guides and pest management advice for every commonly cultivated haworthioid.