Overview

Brief Summary

Albuca is a genus of more than 100 species belonging to the Hyacinthaceae family, to be precise in the subfamily Ornithogaloideae, an Eurasian and African subfamily. This genus is apparently most closely related to Ornithogalum. Some of the new taxonomy proposes including this genus in the Asparagaceae family however.

All Albuca species grow from bulbs, and most have a dormancy period after flowering whereby they lose their leaves. The flower scape is, like almost all Hyacinthaceae, unbranched. Most species only produce one scape per growing season, although some, such as Albuca flaccid and Albuca maxima, may produce two or more; the tropical African species may produce scape after scape after scape in optimal conditions.

The majority of species are winter-growers, mainly originating from the south-west Cape and northwards into Namaqualand, South Africa. The genus also extends into tropical Africa and Arabia, where there are comparatively fewer species.

The most characteristic feature of the genus is the shape of the flower. The outer 3 tepals spread out like any normal flower, but the inner 3 stay more or less closed. The general appearance is therefore somewhat like a snowdrop Galanthus. The flowers do come in a limited color range, white and yellow through to green, but are usually embellished with a green stripe down the middle of each outer tepal. Some species also have the tips of the inner, closed tepals colored differently, either with white or bright yellow. Flowers are either presented in a nodding or drooping formation, or erect on firm pedicels (flower stalks). The tropical African species, on the other hand, have flowers on such short pedicels that the only position they can hold is sideways.

Although there is not a great diversity in the shape of the flowers, there is however a fascinating range of leaf form. Some species do admittedly have rather uninteresting foliage, others have such unusual leaves that they could be grown as a foliage plant in their own right. Leaves can be boat-shaped, coiled into corkscrew shapes, or narrow and wavy like a slithering snake. Some of the above information and information about the species was furnished by Julian Slade in his Introduction to the Pacific Bulb Society topic of the week on Albuca in July 2003.

Because most species rarely produce offsets, growing from seed is the best way to increase stocks, and is usually the only way to obtain most species. All species, however, are extremely easily raised from seed, sown at about the same time adult plants come into active growth. Fresh seed often germinate within a week of sowing, often with 100% germination. The seed is short lived however and probably needs to be started within six months for good germination. Seedlings usually flower in their third year.

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Comprehensive Description

Description

Bulbous, perennial herbs. Leaves linear to lorate, forming a tubular basal sheath around the cylindric stem. Flowers in terminal racemes. Bracts acuminate, not spurred. Perianth erect or drooping; segments 6, free or fused near the base, oblong, white or yellow with a broad green or brown central stripe; 3 outer spreading, 3 inner connivent, hooded at apex. Stamens 6, all fertile or outer 3 sterile. Filaments winged and expanded below to enfold the ovary. Capsule ovoid to spherical, 3-lobed. Seeds flat, semi-circular, black, shiny, papillose.
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© Mark Hyde, Bart Wursten and Petra Ballings

Source: Flora of Zimbabwe

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Evolution and Systematics

Functional Adaptations

Functional adaptation

Leaves gather water: geophytes
 

Leaves of geophytes collect and retain water from fog and dew by morphological adaptation of their aerial parts.

     
  "In the semidesert of Namaqualand and adjacent regions of the former Cape Province, South Africa, there occurs an assemblage of geophytes belonging to eight monocot families and some Oxalis species that exhibit special morphological adaptations of their aerial parts to harvest and absorb water from dew and fog, the main source of moisture in this region...These morphomes, rare elsewhere among monocotyledons, promote an increased deposit of dew and fog by enlargement of surfaces and edges, keeping at the same time the overall size of the leaves restricted. They improve the water budget of these plants in three ways: (1) remnant water on the aerial parts retards the transpiration stress at day-time; (2) although special organs for direct absorption seem to be absent, field and laboratory tests show, that considerable uptake of water occurs but in quantities not exceeding that capacity found in many non-desert plants; (3) the water harvest of the leaves dripping to the soil and reaching the root zone, where it is stored in tubers, bulbs, corms and rhizomes, appears to be the main contribution. Experiments using artificial, directional fog and metal models imitating the natural profiles demonstrate that a surplus of water in efficiency rates of 0.1–66% is collected by the various surface types compared to a standard model with a non-sculptured (plain) frontal surface of the same size." (Vogel S; Müller-Doblies U. 2011:3)

"The peculiar leaf structures they exhibit [described in next quote], plus a special kind of ciliation, – structures rarely found in the plant kingdom outside our region – apparently induce dew and fog water to settle more copiously than on plain leaves." (Vogel S; Müller-Doblies U. 2011:29)

"Although among the geophytic Namaqualand monocot species a fair number bearing 'conventional' foliage occur, a great deal exhibit a striking peculiarity: The leaves, rarely axes and leaf appendages, are curiously modified, being twisted, crisped, curled, pleated or undulate in many different ways, and/or their pilosity has an uncommon appearance. Resident botanists aware of this oddity, therefore call the area the “curly-whirly-country”. Members of 8 families: Amaryllidaceae (55 sp.), Anthericaceae (1 sp.), Asphodelaceae (13), Colchicaceae, Eriospermaceae (20), Hyacinthaceae (100), Hypoxidaceae (6), Iridaceae (80), and Orchidaceae (4) have this trait in common, amounting to 294 species (Table 1, Figs. 3–41). Among dicotyledons, only some species of Oxalis seem to join...the water stress remains as potential motivation. (Vogel S; Müller-Doblies U. 2011:18,21)
  Learn more about this functional adaptation.
  • Vogela S; Müller-Doblies U. 2011. Desert geophytes under dew and fog: The “curly-whirlies” of Namaqualand (South Africa). Flora. 206: 3-31.
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Source: AskNature

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Molecular Biology and Genetics

Molecular Biology

Statistics of barcoding coverage

Barcode of Life Data Systems (BOLD) Stats
Specimen Records: 52
Specimens with Sequences: 47
Specimens with Barcodes: 44
Species: 20
Species With Barcodes: 20
Public Records: 36
Public Species: 19
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Source: Barcode of Life Data Systems (BOLD)

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Barcode data

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Source: Barcode of Life Data Systems (BOLD)

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Wikipedia

Albuca

Albuca is a genus of plants in the family Asparagaceae, subfamily Scilloideae.[1] Most of the 30 species of bulbous plants in this genus are native to Southern Africa, only a few are suited for cultivation. Leaves range in length from 3 in(8 cm) to 4 ft(1.2 m) and may be flat or keeled. Scented flowers with 6 petals in bell-shaped, are yellow or greenish white, in loose racemes on tall stems. The fruiting capsule has many black seeds.

Cultivation

Suitable for outdoor cultivation only where frosts are light, but can be grown in a conservatory or greenhouse. Grow in full sun in light, free-draining soil, in a sheltered position if light frosts might occur. Propagate from offsets or seed.

Species

Albuca altissima
Albuca aurea
Albuca batteniana
Albuca canadensis
Albuca cirninata
Albuca cooperi
Albuca fastigiata
Albuca flaccida
Albuca glauca
Albuca humilis
Albuca maxima
Albuca namaquiensis
Albuca navicularis
Albuca nelsonii
Albuca pachychlamys
Albuca shawii
Albuca setosa
Albuca viridiflora

References

  • Botanica Sistematica
  • Lord, Tony (2003) Flora : The Gardener's Bible : More than 20,000 garden plants from around the world. London: Cassell. ISBN 0-304-36435-5
  • www.prioryplants.co.uk/81/SouthAfricanplants.aspx
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