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This is a family of 700-900 species of deciduous or rarely evergreen,
bulbous plants, several with brightly coloured flowers, that is
well represented in South Africa.
Description
The plants are deciduous or rarely evergreen perennials with a bulb.
This can sometimes be quite large. The leaves are usually lance-shaped
and soft-textured, with rather slimy sap.
The leaves are mostly held upright but in several species from the
South African winter rainfall area they lie flat against the ground.
Mostly the leaves are smooth and unmarked but in most species of
Ledebouria (also some Lachenalia and Eucomis
from South Africa) the leaves are attractively spotted or streaked
with purple or dark green. Occasionally the leaves may have their
upper surface covered with warts or pustules, or coarse hairs, especially
in species of Lachenalia and Massonia. In some species
the leaves are narrow and needle-like or cylindrical.
The flower stalk is leafless and the flowers are always arranged
in racemes. Sometimes these may be very short so that the flowers
are crowded into a head-like cluster. In the genera Bowiea
and Igidiae the raceme is highly branched and sprawls through
the surrounding vegetation. Each flower arises in the axil of a
bract, which may be large and leaf-like or minute and vestigial.
In the subfamily Urgineoideae the lower bracts have a flattened
spur at their base. In some genera a second smaller bract arises
on the base of the flower stalk, or pedicel, as well.
The
flowers are mostly radially symmetrical with six tepals (petals)
arranged in two whorls of three each. These may be similar to one
another or the inner three may differ slightly from the outer three,
often just in shape but sometimes also in size and markings. In
a very few species of Daubenya the lower flowers in the raceme
are more or less two-lipped and thus bilaterally (not radially)
symmetrical. The flowers vary in colour from dull greenish or grey,
through white, to blue, yellow, orange or red. In several species
of Lachenalia they
are multicoloured, often with dark tips on the outer three tepals.
In some species the flowers are very fragrant. The petals are either
separate or joined at the bottom into a short or long tube. The
flowers of most species last several days but are much shorter-lived
in all species of Drimia, where they last just a few hours
or a single day at most. The six stamens are inserted at the base
of the petals or just within the tube (if present). The ovary is
superior with three locules each containing several to many ovules
attached to the centre. Each flower has a single style.
The fruit is a dry capsule that splits open along three sides to
release the seeds. These are very variable in shape. In most genera
they are tetrahedral or variously angled and without obvious adaptations
for dispersal. Flattened seeds with wing-like edges that are adapted
to wind dispersal characterize the subfamily Urgineoideae whereas
glossy, globose or pear-shaped seeds characterize the subfamily
Hyacinthoideae. No species have fleshy seeds.
Distribution
Throughout Africa and the Mediterranean and near-East into India,
with a few species in western South America. The family is mostly
found in seasonal climates with a pronounced dry season and is rare
in tropical lowlands and forested areas. It is best represented
in southern Africa, particularly in the winter rainfall parts, with
a second centre of diversity in the Mediterranean basin. Somewhere
between 700-900 species are known world-wide, just over half of
them in southern Africa. Almost 200 species alone are known from
the Cape Floral Region. Different botanists have very different
opinions about the boundaries of the genera. The number of genera
recognized from sub-Saharan Africa by different botanists ranges
from around 40 at the one extreme to 15 at the other. The motivation
for these changes has been to accurately reflect the evolutionary
relationships of the species. In the past, genera were often defined
on the appearance of the flowers. With hindsight it seems that in
many cases these differences merely reflected different pollination
strategies between groups of species and not more fundamental differences
in the their evolutionary history.
The family is best represented in open, seasonal habitats. The
richest areas for species in southern Africa are the succulent karoo
and fynbos of the Northern and Western Cape, with most species of
Ledebouria and Eucomis found in the montane grasslands
of eastern South Africa, Swaziland and Lesotho. Fewer species occur
in savanna, semi-arid central karroo and forest.
The
species grow in all sorts of soils, derived from granite, basalt,
dolerite, clay, limestone and sandstone. Most species favour loamy
or clay soils, often among rocks where drainage is good, but some
grow in marshes and others in pure sand. Species grow from the coast
to the top of the interior escarpment at over 3 000 m. Relatively
few species are very localized in occurrence but the species of
Daubenya is a notable exception.
Name and History
The family name is based on the genus Hyacinthus, which actually
comprise just two or three species from the middle East. The genus
Hyacinthus dates from 1753, when it was coined by Swedish
botanist, Carl Linnaeus. Its name derives from the Greek myth in
which a beautiful flower, variously described as dark red or purple,
sprung from the blood of the handsome youth Hyacinthus, the beloved
of Apollo and accidentally struck down by the god. Several different
plants have been identified with the myth but it is most likely
that it originally referred to Gladiolus italicus, whose
lower petals bear graphic markings that could be construed to represent
the Greek letters AI that were supposed to have been inscribed
on the mythological flower.
The circumscription of the genera and the relationships between
them have long been contentious. Recent DNA analyses have provided
the first firm foundation for subdividing the family and it is now
accepted that there are four subfamilies:
- Subfamily Oziröeoideae contains the single genus
Oziröe with five species from western South America.
They resemble small species of Ornithogalum with whitish,
star-shaped flowers.
Subfamily
Urgineoideae contains about 100 species. In the classification
of Manning et al. (2004) these are distributed among three genera.
The subfamily is recognized by the spurred bracts at the base
of the flowers; the seeds are flattened and wrinkled with a rim-like
wing; and the bulbs are often highly poisonous, containing characteristic
toxic steroids (bufodienaloids). The largest genus, Drimia,
is recognized by its short-lived flowers, each lasting just a
few hours or up to a single day. New buds open each day so that
usually only one or a few flowers are open at a time. The remaining
two genera in the subfamily, Bowiea (Africa) and Igidia
(Madagascar) have just a single species each and have longer-lived
flowers and highly branched inflorescences that sprawl among the
surrounding vegetation.
- Subfamily Ornithogaloideae contains around 200 species.
The subfamily is recognized by its flattened or angled seeds without
peripheral wings. The flowers are usually whitish or green to
brown but O. dubium has bright yellow or orange flowers.
Many species are poisonous, containing toxic cardenolids. The
genera in this family have been most radically affected by the
various treatments. In the classification of Manning et al. (2004)
all of the species are contained within the single genus Ornithogalum.
This includes those previously placed in genera such as Albuca,
Dipcadi and Galtonia.
- Subfamily Hyacinthoideae includes the remaining species
(just over 200 in sub-Saharan Africa). It contains some of the
most colourful species in the family, including blue Hyacinthus
and Scilla, and multicoloured Lachenalia. Although
for long considered to occur in southern Africa, the genus
Scilla is now known to be strictly northern hemisphere and
the southern African species previously included in it have been
accomodated in several other genera, mostly with just one or a
few species each. (Scilla natalensis = Merwilla
plumbea)
Ecology
Members of Hyacinthaceae occur in a great variety of habitats. About
the only place they do not grow is in the sea itself, although several
species of Lachenalia and Ornithogalum grow in coastal
sands within reach of the spray. Most species are adapted to seasonal
climates that have a pronounced dry or cold period unfavourable
for plant growth and during which the plants are dormant. As a result,
most species are deciduous. Evergreen species are restricted to
subtropical forests or savannah, temperate grasslands and perennially
moist fynbos. A few species grow in marshes or along streams and
some even grow only in the spray of seasonal waterfalls.
The above ground parts (leaves and stems) of deciduous species
die down when the bulb or corm enters dormancy. The plants thus
survive periods that are unfavourable for growth by retreating underground.
This is particularly useful in grasslands and fynbos, which are
adapted to regular burning in the dry season. At this time the plants
are dormant and their bulbs or corms are able to survive the heat
of the fires underground. Veld fires clear the soil surface of competing
vegetation, as well as fertilize it with ash. With the arrival of
the first rains, the dormant corms are ready to burst into growth,
sending up flowers and stems before they can be shaded out by other
vegetation. Many species of Drimia delay their flowering
until the dry season, at which time the leaves are withered and
are often blown away.
The
family has a relatively diverse pollination ecology, especially
in winter rainfall southern Africa. Most species are pollinated
by various species of solitary bees but some, like the genus Veltheimia,
and a few species of Lachenalia and Daubenya, are
adapted to pollination by sunbirds. These species typically have
red to orange, trumpet-like flowers that secrete large amounts of
nectar. The group of species previously placed in Dipcadi
(now included by some in Ornithogalum) are adapted to pollination
by moths, and secrete a rather strong fragrance at night. The brightly
coloured species of Ornithogalum¸ like O. dubium,
and Daubenya aurea, are pollinated by monkey-beetles while
some species of Massonia are visited by rodents..
Economic and cultural value
Several genera are important in horticulture, both as cut flowers
and as garden plants. The most important cut flowers are Ornithogalum
thyrsoides and O. conicum, known affectionately as chinkerinchees
for the squeaking sound that their stems produce when rubbed gently
together. These long-lasting flowers were shipped to Britian in
large numbers from South Africa during the Victorian period. Among
the garden plants the genera Hyacinthus, Hyacinthoides and
Muscari are the most important Mediterranean ones while among
the South Africa genera, Ornithogalum (Galtonia), Veltheimia
and Eucomis are widely cultivated. The evergreen Drimiopsis
(previously known as Drimiopsis maculata but now included
in the genus Ledebouria as L. petiolata) is a very
popular house-plant, producing attractive arrow-shaped leaves marked
with dark green spots.
Species of Orntihogalum are among the most poisonous plants
in South Africa and may lead to stock losses if contaminated fodder
is eaten. Species of Drimia and Bowiea are also highly
toxic but are used in small doses in traditional medicine to treat
various illnesses. Overdosage can be fatal.

In the Garden
Species of Hyacinthaceae are generally easy to cultivate and flower
regularly as long as their need for a resting season is taken into
account. Otherwise the bulbs are prone to rotting. Generally speaking,
species from the east coast, which has a less seasonal climate,
are easiest in gardens. This includes Veltheimia bracteata
and species of Eucomis. Species from the summer rainfall
parts require a dry winter resting period whereas those from the
winter rainfall region require a cool, moist winter growing season
and a dry summer.
References and further reading
- Leistner, O.A.(ed.). 2000. Seed plants of southern Africa: families
and genera. Strelitzia 10. National Botanical Institute,
Pretoria.
- Manning, J., Goldblatt, P. & Snijman, D. 2002. The color
encyclopedia of Cape bulbs. Timber Press, Oregon.
- Manning,J., Goldblatt, P. & Fay, M. 2004. A revised generic
synopsis of Hyacinthaceae in sub-Saharan Africa, based on molecular
evidence, including new combinations and the new tribe Pseudoprospereae.
Edinburgh Journal of Botany 60: 533-568.
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John Manning
Compton Herbarium
October 2004
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