Belongs within: Petrosaviidae.
The Hypoxidaceae are a family of rhizomatous or cormous plants found mostly in the Southern Hemisphere and tropical Asia. Flowers are typically white or yellow, and peduncles are associated with two opposite subulate bracts (Healy & Edgar 1980).
Star-grass
Published 14 April 2014
It does not require a great deal of insight to understand why the plant pictured above has acquired the vernacular names of ‘star-grass’ or ‘gold-star’. This small native of North America is one of the few representatives in that region of the family Hypoxidaceae, a group of about 150 species of thin-leaved monocots that is most diverse in the Southern Hemisphere, particularly in Africa. Most Hypoxidaceae are small like the North American gold-star, though the Asian hill coconut Curculigo latifolia may be over a metre in height. All grow from underground corms or rhizomes. Their flowers have the typical monocot arrangement of three sepals and three petals, and are most commonly yellow to pink in colouration. They mostly produce little scent (some have a faint sweet scent), and usually attract pollinators by offering pollen as a reward. Some species are grown as ornamentals, but for the most part the Hypoxidaceae are not that significant economically. The tubers of the African potato Hypoxis hemerocallidea (which, despite its vernacular name, does not seem to be eaten as a vegetable per se) have been used to make a medicinal tea; it has become particularly widely used in recent years to supposedly alleviate the symptoms of HIV, but tests of its actual efficacy remain in progress.
Recent authors have recognised up to ten genera within the Hypoxidaceae, but a phylogenetic analysis of the family by Kocyan et al. (2011) lead them to suggest the reduction of that number to four or six, depending on how one might chose to deal with the position of Hypoxidia. This is a distinctive genus of two species found on the Seychelles. Flowers of Hypoxidia are a dark red-brown colour, and in contrast to the weak scent of other Hypoxidaceae they have a strong foetid odour that attracts flies as pollinators. Kocyan et al.‘s phylogenetic analysis placed Hypoxidia as sister to the other species of Hypoxidaceae found on the Seychelles, Curculigo seychellensis, and the two together were placed as sister to a clade containing the remaining species of Curculigo (as well as species of Molineria, which Kocyan et al. suggested be synonymised with Curculigo). Curculigo species bear their flowers at the base of the plant; the ovary is actually found beneath the ground, with the corolla borne above the ground on an elongate tubular rostrum. This rostrum is particularly long in C. seychellensis, up to 12 cm. Curculigo seychellensis also has bifurcated leaves that make it look superficially like a palm seedling. It remains to be settled whether future authors will prefer to place C. seychellensis in its own new genus, or to sink Hypoxidia into Curculigo.
The remaining Hypoxidaceae can be divided between the genera Hypoxis (containing Rhodohypoxis as a junior synonym), Empodium and Pauridia (containing Spiloxene and Saniella as synonyms, as well as some Australian species previously placed in Hypoxis). Members of the genera Empodium and Pauridia produce annual corms, while Hypoxis species have tuberous rhizomes. Empodium and Pauridia differ in features of the flowers and seeds (Kocyan et al. 2011). The two African Pauridia species previously classified as Saniella resemble Curculigo in having subterranean ovaries. It is perhaps unfortunate that the name Pauridia, previously restricted to two particularly small African species only a couple of centimetres in height, takes priority over Spiloxene, previously used for a larger group of about thirty species. But such are the vagaries of nomenclature, and that which we now call Pauridia capensis (Snijman & Kocyan 2013) will smell as… generally indifferent, actually, but it at least looks pretty specky.
A spoonful of lemba
Published 9 September 2014
As noted above, the south-east Asian plant known as lemba has been through a couple of names over the years. Some sources will refer to it as Molineria latifolia, while others will call it Curculigo latifolia. The genera Molineria and Curculigo have been distinguished based on the presence of beaked (Curculigo) or unbeaked (Molineria) fruits and seeds, but the phylogenetic analysis of Hypoxidaceae by Kocyan et al. (2011) did not find this character to correlate with phylogeny. They therefore proposed to stop recognising the two genera as distinct, merging all species under Curculigo.
Curculigo latifolia is one of the largest species in the Hypoxidaceae. It is mostly found growing in damp, shaded locations, and the long-petioled leaves coming from an erect central rhizome can be a metre in length. Its small yellow flowers are placed at the base of the plant, at ground level; this distinguishes this species from various large orchid species found in the same region that may also be referred to as ‘lemba’ (or ‘lumbah’, or some other spelling/linguistic variant). The flowers give rise to small white berries, about an inch in size, with a distinct beak.
Uses of this plant were recently reviewed by Lim (2012). The leaves provide a strong, lightweight fibre that is used to make nets, rope and cloth. The roots are brewed to treat various illnesses. However, the feature of this plant that has received the most attention in recent years is the fruit. These are edible, and are said to taste a bit like a sweet cucumber. The reason they have aroused interest, though, is that after eating one, anything else eaten within the next ten minutes or so will also taste sweet. This effect has been traced to a protein in the fruit, variously called neoculin or curculin, that has been reported to have several hundreds times the sweetness relative to weight of sucrose. Curculin has consequently been proposed as a potential low-calorie sweetener (to which I say, I’m sure it can’t possibly taste worse than stevia), though one limitation is that the protein becomes denatured at temperatures above fifty degrees and loses its sweetening properties. As yet, though, it doesn’t look like lemba sweetener has made it onto the commercial market.
Systematics of Hypoxidaceae
Characters (from Healy & Edgar 1980): Herbs with tuberous rhizome or corm covered with membranous or fibrous sheaths. Leaves usually all basal, often with long hairs. Flowers bisexual, actinomorphic, mostly white or yellow, solitary, or in spicate, racemose or subumbellate inflorescences; segments 6, subequal, free or basally connate. Stamens usually 6, inserted at base of perianth-segments; anthers often 2-lobed at base, opening by longitudinal slits. Ovary inferior, trilocular; ovules usually many, in two series on axile placenta in each locule. Fruit usually a capsule crowned by persistent perianth; dehiscence by irregular, often more or less circular slits; fruit occasionally fleshy and indehiscent. Seeds small, often black.
<==HypoxidaceaeS06 |--EmpodiumRG07 `--+--RhodohypoxisRG07 `--Hypoxis Linnaeus 1759RG07, ME70 (see below for synonymy) |--H. hirsuta [incl. *H. erecta L. 1759]CC87 |--H. arillacea Henderson 1987 [incl. H. hygrometrica var. elongata Benth. 1873]CC87 |--H. aureaSS72 |--H. dinteriCV06 |--H. exilis Henderson 1987CC87 |--H. hygrometrica Labill. 1805CC87 | |--H. h. var. hygrometricaCC87 | |--H. h. var. splendida Henderson 1987CC87 | `--H. h. var. villosisepala Henderson 1987CC87 |--H. marginata Br. 1810CC87 |--H. nervosa Henderson 1987CC87 |--H. pratensis Br. 1810 [=H. hygrometrica var. pratensis (Br.) Benth. 1873]CC87 | |--H. p. var. pratensisCC87 | `--H. p. var. tuberculata Henderson 1987CC87 |--H. pusilla Kunth in H. B. & K. 1816HE80 `--H. wrightiiJ87 Hypoxidaceae incertae sedis: SaniellaS06 PauridiaS06 |--P. longitubaS06 `--P. minutaS06 Curculigo Gaertner 1788S06, CC87 [incl. Molineria Colla 1824CC87] |--*C. orchioides Gaertner 1788CC87 |--C. capitulata (Lour.) Kuntze 1891DS04, CC87 (see below for synonymy) |--C. ensifolia Br. 1810CC87 | |--C. e. var. ensifolia (see below for synonymy)CC87 | `--C. e. var. longifolia Benth. 1873CC87 `--C. latifoliaK03 [=Molineria latifoliaP88] Spiloxene Fourcade 1932S06 (see below for synonymy) |--S. albaS06 |--S. canaliculataS06 |--S. capensisS06 |--‘Hypoxis’ gardneri Henderson 1987CC87 |--‘Hypoxis’ glabella Br. 1810 [=Ianthe glabella (Br.) Williams 1901]CC87 | |--H. g. var. glabella (see below for synonymy)CC87 | `--H. g. var. leptantha (Benth.) Henderson 1987 (see below for synonymy)CC87 |--S. nana Snijman 2006S06 |--‘Hypoxis’ occidentalis Benth. 1873CC87 | |--H. o. var. occidentalisCC87 | `--H. o. var. quadriloba (Muell.) Henderson 1987 [=H. glabella var. quadriloba Muell. 1867]CC87 |--‘Hypoxis’ ovata [=*Ianthe ovata]CC87 |--S. pusilla Snijman 2006S06 |--S. scullyiS06 |--S. serrataS06 `--‘Hypoxis’ vaginata Schldl. 1847CC87 |--H. v. var. vaginataCC87 `--H. v. var. brevistigmata Henderson 1987CC87
Curculigo capitulata (Lour.) Kuntze 1891DS04, CC87 [=Leucojum capitulatum Lour. 1790CC87, Molineria capitulata (Lour.) Herbert 1837CC87; incl. *M. plicata Colla 1824CC87, Curculigo recurvata Aiton 1811CC87, M. recurvata (Aiton) Herbert 1837CC87]
Curculigo ensifolia Br. 1810 var. ensifolia [=C. ensifolia var. typica Domin 1915 (nom. inv.); incl. C. ensifolia var. albopilosa Domin 1915, C. ensifolia var. petiolata Domin 1915]CC87
Hypoxis Linnaeus 1759RG07, ME70 [=H. subg. Euhypoxis Baker 1878 (nom. inv.)CC87, H. sect. Euhypoxis (Baker) Benth. & Hook. 1883 (nom. inv.)CC87]
‘Hypoxis’ glabella Br. 1810 var. glabella [incl. H. hookeri Geerinck 1969, H. pusilla Hooker 1858 non Kunth 1816, H. glabella var. pusilla (Hook.) Muell. ex Maiden & Betche 1916]CC87
‘Hypoxis’ glabella var. leptantha (Benth.) Henderson 1987 [=H. leptantha Benth. 1873, Ianthe leptantha (Benth.) Williams 1901]CC87
Spiloxene Fourcade 1932S06 [incl. Ianthe Salisbury 1866 non Janthe Grisebach 1844S06, Hypoxis subg. Ianthe Baker 1878CC87, H. sect. Ianthe (Baker) Benth. & Hook. 1883CC87]
*Type species of generic name indicated
References
[CC87] Clifford, H. T., J. G. Conran, J. B. Williams, R. J. F. Henderson, H. J. Hewson, E. M. Watson, G. J. Keighery, D. M. Churchill, I. R. H. Telford, A. Thongpukdee, N. H. Brittan, A. S. George, W. T. Stearn & T. D. Macfarlane. 1987. Liliaceae. Flora of Australia 45: 148–419.
[CV06] Craven, P., & P. Vorster. 2006. Patterns of plant diversity and endemism in Namibia. Bothalia 36 (2): 175–189.
[DS04] Davis, J. I., D. W. Stevenson, G. Petersen, O. Seberg, L. M. Campbell, J. V. Freudenstein, D. H. Goldman, C. R. Hardy, F. A. Michelangeli, M. P. Simmons, C. D. Specht, F. Vergara-Silva & M. Gandolfo. 2004. A phylogeny of the monocots, as inferred from rbcL and atpA sequence variation, and a comparison of methods for calculating jackknife and bootstrap values. Systematic Botany 29 (3): 467–510.
[HE80] Healy, A. J., & E. Edgar. 1980. Flora of New Zealand vol. 3. Adventive cyperaceous, petalous and spathaceous monocotyledons. P. D. Hasselberg, Government Printer: Wellington (New Zealand).
[J87] Judd, W. S. 1987. Floristic study of Morne La Visite and Pic Macaya National Parks, Haiti. Bulletin of the Florida State Museum—Biological Sciences 32 (1): 1–136.
Kocyan, A., D. A. Snijman, F. Forest, D. S. Devey, J. V. Freudenstein, J. Wiland-Szymańska, M. W. Chase & P. J. Rudall. 2011. Molecular phylogenetics of Hypoxidaceae—evidence from plastid DNA data and inferences on morphology and biogeography. Molecular Phylogenetics and Evolution 60 (1): 122–136.
[K03] Kulip, J. 2003. An ethnobotanical survey of medicinal and other useful plants of Muruts in Sabah, Malaysia. Telopea 10 (1): 81–98.
Lim, T. K. 2012. Edible Medicinal and Non-Medicinal Plants vol. 4. Fruits. Springer.
[ME70] Moore, L. B., & E. Edgar. 1970. Flora of New Zealand vol. 2. Indigenous Tracheophyta: Monocotyledones except Gramineae. A. R. Shearer, Government Printer: Wellington (New Zealand).
[P88] Polunin, I. 1988. Plants and Flowers of Malaysia. Times Editions: Singapore.
[RG07] Ramírez, S. R., B. Gravendeel, R. B. Singer, C. R. Marshall & N. E. Pierce. 2007. Dating the origin of the Orchidaceae from a fossil orchid with its pollinator. Nature 448: 1042–1045.
[SS72] Singh, V., & H. Singh. 1972. A contribution to the flora of Gangolihat block in Pithoragarh District. Journal of the Bombay Natural History Society 69 (2): 352–368.
[S06] Snijman, D. A. 2006. Two new species of Spiloxene (Hypoxidaceae) from the northwestern Cape, South Africa. Bothalia 36 (2): 133–138.
Snijman, D. A., & A. Kocyan. 2013. The genus Pauridia (Hypoxidaceae) amplified to include Hypoxis sect. Ianthe, Saniella and Spiloxene, with revised nomenclature and typification. Phytotaxa 116 (1): 19–33.