1. Hypoxidaceae R.Br.

    1. This family is accepted.

[NTK]

Dutilh, J.H.A. (2009). Neotropical Hypoxidaceae.

Morphology
Description

Perennial geophytes, sparcely to densely pubescent , with a vertical rhizome often surrounded with fibers of old leaves. Leaves rosulate, sessile , flat, with prominent parallel veins . Inflorescences often several, generally on a scape, scape sometimes very short and subterranean, umbel -like, with 1-3 pedicellate to sessile flowers subtended by bracts;  pedicel not articulate . Flowers hermaphrodite , actinomorphic ; tepals 6, in two whorls apparent or not, petaloid , free , yellow, 3 outer ones sometimes greenish and pubescent on  abaxial side; stamens 6 opposite tepals with sagittate anthers; filaments inserted on the base of the tepals; ovary inferior, tri-carpellate and tri-locular, sometimes unilocular maybe due to incomplete septa, several ovules per locule ; style at apex of ovary , solitary, erect ; stigma capitate , trilobate. Fruit capsule with irregular dehiscence, or fleshy , with 1- several seeds per locule . Seeds black, more or less globose .

General Description
Notes on delimitation
  • The family Hypoxidaceae, its genera and species have a complex taxonomic history, not yet fully understood.
  • The family Hypoxidaceae was considered by Rudall (2003) to have a close morphological relationship with Orchidaceae. It is now considered to be close to Asteliaceae and Lanariaceae.
  • In the family Hypoxidaceae, species from genera Hypoxidia Friedmann and Spiloxene Salisb. have intermediate ovary between trilocular and unilocular.
  • Ravenna created genus Heliacme Ravenna (based on Curculigoscorzonerifolia Lam.) for the Neotropics, on the basis of  a unilocular ovary and dry fruit (as compared with the rest of Curculigo Gaertn. which is otherwise African). But the fruit is not dry, and the ovary remains yet to be better understood in the genus.
Number of genera
  • Two in the Neotropics: Hypoxis and Curculigo.
Distribution
Distribution in the Neotropics
  • The largest genus of the family is Hypoxis L., but this has many taxonomic problems with delimitation of its species, as they have a high degree of apomixy. It is found in tropical and subtropical areas of all continents.
  • The family is found mainly in Africa, but Hypoxis and Curculigo have a few native species in the Neotropics.
Diagnostic
Useful tips for generic identification
  • Hypoxis is characterized by the aerial flower scape and dry fruit, and Curculigo by the subterranean ovary and fleshy fruit.
  • Curculigo has only one known species in the Neotropics, which has a flower that appears at ground level and subterranean fruits.  C. scorzonerifolia (Lam.) Baker is characterized by the umbel with a sessile or almost sessile flower.
Literature
Important literature

Nordal, I. (1998). Hypoxidaceae. Pp. 286-295. In: Kubitzki, K. (ed.), The Families and Genera of Vascular Plants: Monocotyledons - Lilianae (except Orchidaceae). Springer-Verlag, Berlin.

Ravenna, P. (2003). Heliacme Ravenna, a new genus of New World Hypoxidaceae. Onira 8(2): 5-9.

Seubert, M. (1847). Hypoxideae. Pp. 48-52. In Martius, CFP. Flora Brasiliensis. Lipsiae

[FWTA]

Hypoxidaceae, F.N. Hepper. Flora of West Tropical Africa 3:1. 1968

Habit
Herbs with a tuberous rhizome or a corm
Leaves
Leaves mostly all radical, usually prominently nerved and often clothed with long hairs
Flowers
Flowers solitary, spicate, racemose or subumbellate, mostly white or yellow, actinomorphic
Perianth
Perianth-tube nothing or very short or consolidated into a long beak on top of the ovary; segments 6, spreading, equal
Androecium
Stamens 6 or rarely 3, opposite the perianth-segments and inserted at their base; anthers 2-celled, opening lengthwise
Gynoecium
Ovules numerous in 2 series on axile placentas, or rarely few Ovary inferior, 3-celled, style short or 3 styles separate
Fruits
Fruit a capsule opening by a circular slit or by vertical slits near the top, or indehiscent and fleshy
Seeds
Seeds small; embryo in abundant endosperm
[FZ]

Hypoxidaceae, I. Nordal & C. Zimudzi. Flora Zambesiaca 12:3. 2001

Habit
Herbaceous geophytes perennating by rhizomes or corms with contractile roots (the aerial parts dying back after the growing season)
Leaves
Leaves basal, 1–many, rosulate or tristichous, sessile or pseudopetiolate, ± sheathing at the base, the outermost often reduced to cataphylls; laminas erect or arcuate, linear to lanceolate or oblong-lanceolate to ovate, ± prominently parallel-veined, often V-shaped in cross-section (conduplicate) or ± terete, sometimes plicate, glabrous or pubescent; leaf sheaths with ± broad scarious margins, older leaf bases usually disintegrating into fibrous remnants
Inflorescences
Inflorescences 1–several, terminal, scapose; scapes ± terete or flattened, with flowers solitary or 2–many spicately to racemosely or corymbosely arranged
Flowers
Flowers bisexual, actinomorphic, 3(4)-merous, usually pedicellate
Perianth
Perianth ± persistent; perianth segments (tepals) (4)6, erect or spreading, subequal or somewhat heterochlamydeous, free, or lower part of perianth segments fused below into a narrow tube (the perianth tube in Curculigo)
Androecium
Stamens 6, usually in 2 whorls (3 stamens in Pauridia); filaments short, arising from the base of the tepals; anthers 2-thecous, entire or deeply sagittate, opening introrsely or latrorsely by longitudinal slits
Gynoecium
Ovary inferior, 3-locular with axile placentation (or 1-locular); ovules few to many; style 1, filiform to subulate; stigmas 3–6
Fruits
Fruit a capsule with circumscissile or loculicidal dehiscence, or sometimes ± fleshy and indehiscent
Seeds
Seeds ellipsoid to globose, sometimes with a distinct strophiole(Curculigo), dark brown or black
[FTEA]

Hypoxidaceae, J. Wiland-Szymańska, I. Nordal. Flora of Tropical East Africa. 2006

Habit
Perennial herbs with subterranean corms or rhizomes with contractile roots
Leaves
Leaves in basal, rosulate or tristichous rosette, sessile or pseudopetiolate, ± sheathing at the base, the outermost often reduced to cataphylls; lamina erect or arcuate, linear to lanceolate, ± prominently parallel-veined, often V-shaped in cross section, or terete, sometimes plicate, pubescent, rarely glabrous
Inflorescences
Inflorescences 1-several, racemose, corymbose, spicate or capitate, rarely only one-flowered; scapes flattened or rarely terete
Flowers
Flowers bisexual, rarely andro-dioecious, actinomorphic, usually trimerous; tepals subequal, most often yellow, free
Stamens
Stamens 6, filaments short, arising from the base of the tepals; anthers opening latrorsely or introrsely by longitudinal slits (apical pores in Molineria)
Ovary
Ovary inferior, 3-locular with axile placentation, ovules few to many
Fruits
Fruits indehiscent ( Curculigo and Molineria) or dehiscent ( Hypoxis), opening by a transverse slit (circumscissile) or longitudinal slits (loculicidal).
Seeds
Seeds dark brown or black, ellipsoid to globose.
Distribution
Range: A tropical to subtropical family of 9 genera, mainly in the southern hemisphere. The two genera known in the wild from East Africa, Hypoxis and Curculigo, are pantropical. Molineria, cultivated as an ornamental in East Africa, is of Asiatic origin. Four genera are endemic to South Africa, one is shared between South Africa and Australia, and one is endemic to the Seychelles.
[FTEA]
Use
Corms of some of the species of Hypoxidaceae are used for medicinalpurposes (said to be functional against AIDS, cancer, and gastric problems) and are in great demand at the moment. Especially species of Hypoxis, of which the corms are called „African potatoes” might be endangered due to this.

Images

Hypoxidaceae R.Br. appears in other Kew resources:

First published in Voy. Terra Austral. 2: 576. 1814 [19 Jul 1814] (1814)

Accepted by

  • APG IV (2016) http://dx.doi.org/10.1111/boj.12385

Sources

Flora Zambesiaca
Flora Zambesiaca
http://creativecommons.org/licenses/by-nc-sa/3.0

Flora of Tropical East Africa
Flora of Tropical East Africa
http://creativecommons.org/licenses/by-nc-sa/3.0

Flora of West Tropical Africa
Flora of West Tropical Africa
http://creativecommons.org/licenses/by-nc-sa/3.0

Kew Names and Taxonomic Backbone
The International Plant Names Index and World Checklist of Selected Plant Families 2019. Published on the Internet at http://www.ipni.org and http://apps.kew.org/wcsp/
© Copyright 2017 International Plant Names Index and World Checklist of Selected Plant Families. http://creativecommons.org/licenses/by/3.0

Neotropikey
Milliken, W., Klitgard, B. and Baracat, A. (2009 onwards), Neotropikey - Interactive key and information resources for flowering plants of the Neotropics.
http://creativecommons.org/licenses/by/3.0