Theplants grow from a fleshytuberous root which is asource ofmaltodextrins which are used as asugar substitute. Some species attain a height of 90 cm (35 in).Theflowers are solitary or arranged inracemes. Thepetals and thelip are small. The flowers consist essentially of thesepals. The flowers range in color from very light to dark red.
In aclassification of orchids that waspublished in 2015,Chaseet alii placedSchizodium insynonymy underDisa. They alsodefined the subtribe Disinae as consisting ofPachites,Disa andHuttonaea. This version of Disinae is probably notmonophyletic, but was created as a holding classification, to avoid the unnecessary designation of subtribes before further studies can clarify therelationships of these three genera.[1]
The genus can be split into two groups based on the size of the seeds. Those with relatively large balloon-shaped seeds up to 1.5 mm long belong to theDisa uniflora group. The remaining species have seeds that are smaller than 0.7 mm. TheDisa uniflora group comprises plants that grow along stream sides:Disa uniflora,Disa tripetaloides,Disa cardinalis,Disa caulescens andDisa aurata. They belong to the few species in Orchidaceae that do not rely onmycorrhizal fungi for germination, and are thought to be an adaptation tohydrochory.[17][18] This pattern was later extended to split the genus into summer rainfall species and non-summer rainfall species. Those in the second group addedDisa cornuta to the list ofDisa seeds that germinate readily.[19]
Once very rare in cultivation,Disa uniflora is gaining in popularity as acut flower. However, they are difficult to grow, because of the neededmineral composition of thepotting soil. Also, if exposed to excessive moisture, they can be easily killed byrot.
The following species have been used to create more than 400 hybrids :Disa cardinalis,Disa caulescens,Disa racemosa,Disa tripetaloides,Disa uniflora,Disa aurata andDisa venosa.
Disa× brendae (D. caulescens ×D. uniflora) (South Africa, SW. Cape Prov.)
Disa× maculomarronina (D. hircicornis ×D. versicolor) (S. Africa)..
Disa× nuwebergensis (D. caulescens ×D. tripetaloides) (South Africa, Cape Prov.).
Disa× paludicola (D. chrysostachya ×D. rhodantha) (South Africa, KwaZulu-Natal).
^abMark W. Chase; Kenneth M. Cameron; John V. Freudenstein; Alec M. Pridgeon; Gerardo A. Salazar; Cássio van den Berg; André Schuiteman (2015)."An updated classification of Orchidaceae".Botanical Journal of the Linnean Society.177 (2):151–174.doi:10.1111/boj.12234.
^Peter Jonas Bergius. 1767.Descriptiones Plantarum ex Capite Bonae Spei: 348. (SeeExternal links below).
^Umberto Quattrocchi. 2000.CRC World Dictionary of Plant Names volume II. CRC Press: Boca Raton; New York; Washington,DC;, USA. London, UK.ISBN978-0-8493-2676-9 (vol. II). (seeExternal links below).
^Waterman, Richard J.; Pauw, Anton; Barraclough, Timothy G.; Savolainen, Vincent (2009). "Pollinators underestimated: A molecular phylogeny reveals widespread floral convergence in oil-secreting orchids (sub-tribe Coryciinae) of the Cape of South Africa".Molecular Phylogenetics and Evolution.51 (1):100–110.doi:10.1016/j.ympev.2008.05.020.PMID18586527.
^Johnson, S. D.; Brown, M. (2004). "Transfer of pollinaria on birds' feet: a new pollination system in orchids".Plant Systematics and Evolution.244 (3):181–188.doi:10.1007/s00606-003-0106-y.S2CID23288375.
^Douzery, Emmanuel J. P.; Pridgeon, Alec M.; Kores, Paul; Linder, H. P.; Kurzweil, Hubert; Chase, Mark W. (1999-06-01). "Molecular phylogenetics of Diseae (Orchidaceae): a contribution from nuclear ribosomal ITS sequences".American Journal of Botany.86 (6):887–899.doi:10.2307/2656709.ISSN0002-9122.JSTOR2656709.PMID10371730.
^Bytebier, Benny; Bellstedt, Dirk U.; Linder, Hans Peter (2007). "A molecular phylogeny for the large African orchid genusDisa".Molecular Phylogenetics and Evolution.43 (1):75–90.doi:10.1016/j.ympev.2006.08.014.PMID17081772.
^Benny Bytebier; Dirk U. Bellstedt; Hans Peter Linder (2008). "A New Phylogeny-Based Sectional Classification for the Large African Orchid GenusDisa".Taxon.57 (4):1233–1251.doi:10.1002/tax.574015.JSTOR27756776..
^Linder Hans Peter (1981). "Taxonomic studies on the Disinae: 2. A revision of the genusSchizodium Lindl".Journal of South African Botany.47:339–371.
^Thompson, David Ian (2003).Conservation of select South African Disa Berg. Species (Orchidaceae) through in vitro seed germination. University of Natal.
^Kurzweil, H. (September 1993). "Seed morphology in Southern African Orchidoideae (Orchidaceae)".Plant Systematics and Evolution.185 (3–4):229–247.doi:10.1007/BF00937660.S2CID41321812.
^Thompson, Dave I.; Edwards, Trevor J.; Staden, Johannes van (2001). "In Vitro Germination of Several South African Summer Rainfall Disa (Orchidaceae) Species: Is Seed Testa Structure a Function of Habitat and a Determinant of Germinability?".Systematics and Geography of Plants.71 (2):597–606.doi:10.2307/3668704.JSTOR3668704.
^Anthony Huxley, Mark Griffiths, and Margot Levy (1992).The New Royal Horticultural Society Dictionary of Gardening. The Macmillan Press,Limited: London. The Stockton Press: New York.ISBN978-0-333-47494-5 (set).
^Eric Harley, Sid Cywes, and H. Peter Linder. 2013.A Disa Companion: The Art and Science of Disa Cultivation. Author House. 123 pages.ISBN978-1-48179-767-2.
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