Accepted Scientific Name: Haworthia cymbiformis var. obtusa (Haw.) Baker
J. Linn. Soc., Bot. 18: 209 (1880)
Haworthia obtusa (Haworthia cymbiformis var. obtusa) Photo by: Valentino Vallicelli
Origin and Habitat: Fort Beaufort, Eastern Cape, South Africa.
Synonyms:
See all synonyms of Haworthia cymbiformis
Description: Haworthia cymbiformisSN|14982]]SN|975]] var. obtusa is one of the innumerable morphological forms of the very variable Haworthia cymbiformisSN|975]]SN|975]] characterized by denser rosettes forming round clumps. It has peculiar bright green leaves that looks like molded glass. The leaves are thicker, obovate, with entire margins, and leaf-tips are rather obtuse or rounded and pellucid. It is vaguely reminiscent of Haworthia cooperiSN|975]]SN|14982]] var. truncata.
Habit: It is a spreading ground cover succulent forming dense mats of very succulents and juicy leaf-rosettes partially sunken into the soil, and reaching a diameter of 15 (or more) centimetres. In habitat only the leaf tips, which has a finger-tip-like appearance, protrude from the soil surface.
Roots: Superficial.
Stem: Stemless or shortly caulescent
Rosette: Stemless, dense, 20–25 leafed, 3-10 cm in diameter.
Leaves: Succulent, soft, very juicy, obovate with entire margins, and leaf-tips are rather obtuse or rounded and pellucid..
Flowers: Relatively inconspicuous whitish/greenish with a light pinkish-brown keel, peduncle simple, 15 cm long; raceme lax, 15 long; lower pedicels 4-6 mm long; bracts small, ovate; perianth 2 cm long; segments nearly as long as the tube.
Blooming season: Spring to summer.
Chromosome number: n = 7
Subspecies, varieties, forms and cultivars of plants belonging to the Haworthia cymbiformis group
- Haworthia cuspidata Haw.: supposedly a cross between Haworthia retusa and Haworthia cymbiformis.
- Haworthia cymbiformis (Haw.) Duval: has very plump and juicy leaves which are swollen with stored water. It comes from a wide area, and is very variable. Distribution: East London to Port Elizabeth, and Adelaide and Committees on the Fish River.
- Haworthia cymbiformis f. gracilidelineata (Poelln.) Pilbeam: has small tightly clustered, rosettes up to 3 cm in diameter. Leaves incurved almost completely tranlucent.
- Haworthia cymbiformis var. incurvula (Poelln.) M.B.Bayer: has narrow, incurved leaves, with rounded tranlucent teeth. Distribution: Grahamstown , Eastern Cape, South Africa.
- Haworthia cymbiformis var. obtusa (Haw.) Baker: Distribution: Fort Beaufort, Eastern Cape, South Africa.
- Haworthia cymbiformis f. pallida hort.: Pale form with yellowhis-green leves. Origin: Plants so-named are known only in cultivation.
- Haworthia cymbiformis f. planifolia (Haw.) Pilbeam: always grows at an acute angle, often with the rosette almost perpendicular; it usually grows in shade but reddens if in the sun.
- Haworthia cymbiformis var. ramosa (G.G.Sm.) M.B.Bayer: it is a shortly caulescent form with smaller rosettes.
- Haworthia cymbiformis var. reddii (C.L.Scott) M.B.Bayer: Distribution: Fort Beaufort, ), Eastern Cape, South Africa.
- Haworthia cymbiformis var. setulifera (Poelln.) M.B.Bayer
- Haworthia cymbiformis var. transiens (Poelln.) M.B.Bayer: has translucent green leaves 1,5-2,5 cm long each with 8-10 longitudinal stripes. In ful sun the leaves tend to take a red brown colouring. Margin finely toothed. Distribution: Baviaanskloof and Langkloof , Eastern Cape.
- Haworthia cymbiformis var. umbraticola (Poelln.) M.B.Bayer: has leaf-tips with large clear areas with dark green lines.
- Haworthia cymbiformis f. variegata: has soft, juicy and glassy (almost transparent) leaves which are nicely variegated with light-green and white longitudinal strips with varying amounts of variegation.
- Haworthia planifolia f. agavoides W.Triebner & Poelln.: has large flattened rosettes with very wide leaves.
Bibliography: Major references and further lectures
1) Urs Eggli “Illustrated Handbook of Succulent Plants: Monocotyledons” Springer, 2001
2) Charles L. Scott “The genus Haworthia (Liliaceae): a taxonomic revision” Aloe Books, 1985
3) Stuart Max Walters “The European Garden Flora: Pteridophyta, Gymbospermae, Angiospermae-Monocotyledons” Cambridge University Press, 1984
4) M. B. Bayer “The new Haworthia handbook” National Botanic Gardens of South Africa, 1982
5) John Pilbeam “Haworthia and Astroloba: A Collector's Guide” B. T. Batsford Limited, 1983
6) Gordon D. Rowley “The illustrated encyclopedia of succulents” Crown Publishers, 01/Aug/1978
7) Linda R. Berg “Introductory Botany: Plants, People, and the Environment” Cengage Learning, 02/Mar/2007
8) Dieter J. Von Willert “Life strategies of succulents in deserts: with special reference to the Namib desert” CUP Archive, 1992
9) A. J. van Laren “Succulents other than cacti” Abbey San Encino Press, 1934
10) Walther Haage “Cacti and succulents: a practical handbook” Dutton, 1963
11) Adrian Hardy Haworth “A new Arrangement of the Genus Aloe, with a chronological Sketch of the progressive Knowledge of that Genus, and of other succulent Genera.” In: Transactions of the Linnean Society of London. Band 7, Nummer 1, London 1804
12) Walter Erhardt, Erich Götz, Nils Bödeker, Siegmund Seybold: "Der große Zander" Eugen Ulmer KG, Stuttgart 2008(German.)
13) Christoper Brickell "RHS A-Z Encyclopedia of Garden Plants" Third edition. Dorling Kindersley, London 2003
Cultivation and Propagation: Haworthia are of easy cultivation and relatively low maintenance, which makes them a good houseplant, and can be an excellent subject for the beginning succulentophile (they can grow easily on window sills, verandas and in miniature succulent gardens where they are happy to share their habitat with other smaller succulent plants, or in outdoor rockeries). Haworthias are winter growers and are dormant in the hottest summer months.
Growth rate: They are relatively fast-growing plants that offsets freely to form small clusters quickly.
Soil: They are tolerant of a wide range of soils and habitats, but prefer a very porous potting mix to increase drainage. A non-acid soil is ideal. You can grow a plant in a 10-15 cm pot for years and have perfectly happy plants. For best results, use a shallow pot.
Exposition: The plant needs light shade to shade, but will take full sun part of the day. (with some sun exposure the leaf develops a nice reddish tint and remains compact).
Watering: During the hot summer months, the soil should be kept moist but not overly wet. During the winter months, water only when the soil becomes completely dry. Wet soil quickly causes root and stem rot, especially during chilly winter months. No water should ever be allowed to stand around the roots. Low ambient humidity is always needed.
Fertilization: The plants are fertilized only once during the growing season with a balanced fertilizer diluted to ½ the recommended strength.
Hardiness: Although the plant will survive mild frost if kept dry (hardy as low as -5° C) it should be protected from severe cold and prolonged frost conditions.
Rot: Rot is only a minor problem with Haworthia if the plants are watered and “aired” correctly. If they are not, fungicides won't help all that much. Care must be given in watering, keeping them warm and wet while growing, and cooler and dry when dormant.
Remarks: Haworthias are best planted in a shaded and airy part of the greenhouse, and not too close to the glass roof or sides of the house as the plants can overheat during hot spells.
Propagation: Haworthia are easily propagated by the removal of offshoots or by leaf cuttings in spring or summer. To propagate by leaf cuttings, remove a leaf and let it lie for about one month, giving the wound time to heal. Then lay the leaf on its side with the basal part buried in the soil. This leaf should root within a month or two, and small plants will form at the leaf base. They can also be grown from seed.