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Holothrix
is a widespread African genus and is represented in southern Africa
by 23 species. The plants are mostly slender and insignificant small herbs
and do not look like 'typical' orchids as their flowers are mostly tiny.
Several species are fairly drought-resistant and can be found in arid
and semi-arid areas in the interior of South Africa, as well as in dry
habitats in the more humid parts. There are several species in karooid
scrub and some occur in rock cracks in the Northern Cape, others thrive
in fynbos in the Cape Floristic Region of the Western and Eastern Cape.
There are some species in the montane forests of the Eastern Cape and
KwaZulu-Natal as well as some in the montane and subalpine grasslands
of the Drakensberg mountains and the north-eastern parts of southern Africa.
Flowering generally occurs in spring or summer. While many species are
rarely seen, H. aspera, H. villosa and H. secunda are fairly
common in suitable habitats.
The plants of this genus are characterized by underground root tubers
and one or two basal, ovate and frequently hairy leaves lying flat on
the ground. An interesting feature is that the thick water-storing upper
leaf layer (epidermis) appears translucent. The scape (flower stalk) is
erect and frequently also hairy. The small or medium-sized flowers are
born in unbranched spikes. In colour they range from white, cream, yellow
and green to pinkish-cream. Petals are mostly unlobed, but there are also
species with three- to many-lobed petals. Lips are usually lobed with
three to many lobes which may be hair-like thin; occasionally the lips
are unlobed. The lips are always spurred. The plants are decidous, i.e
they become dormant at the end of the growing season.
Plants of the genus Holothrix are rarely cultivated as they have
very little appeal to growers due to their minute or small flowers.
Selected species and their main distribution
Winter-rainfall area: H. secunda ('tryphia'),
H. mundii, H. aspera
Summer-rainfall area: H. thodei, H. incurva,
H. scopularia, H. orthoceras
Both areas: H. exilis, H. cernua, H. villosa,
H. grandiflora
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