Malvaceae Info (Home)
Lavatera is a genus within the family Malvaceae, which also includes, inter alia, Althaea, Abutilon, Gossypium, Hibiscus, Malva and Sidalcea, and is particularly close to Malva. The 20-25 species of Lavatera have a broadly Mediterranean distribution, stretching to southwest Britain, the Canary Is., Abyssinia, Central Asia and Kashmir, with outlying species in Australia (Lavatera plebeia), California (Lavatera assurgentiflora, Lavatera insularis, Lavatera lindsayi, Lavatera occidentalis and Lavatera venosa), and eastern Siberia.
Lavateras are annual, biennial or short-lived perennial herbs and sub-shrubs. The flowers are pink to purple, or white, or yellow in some forms of Lavatera triloba. The stems and foliage are typically downy or hairy. The fruits consist of a divided capsule containing a ring of nutlets.
Many species of Lavatera are of horticultural merit.
Lavatera is a genus of the sub-family Malvoideae, tribe Malveae and sub-tribe Malvinae of the family Malvaceae. It is particularly close to the true Mallows, Malva. The traditional diagnostic character distinguishing Lavatera from Malva is the epicalyx segments (the leaf-like structures beneath the flowers/fruit) being united at the base. However there are at least 2 species (Lavatera cretica and mauritanica) which show the general form of Lavatera which have the epicalyx segments nearly free, and one variety of Lavatera triloba has the epicalyx segments wholly free. Because of this and other observations it has long been suspected that this diagnostic character is not a good character for distinguishing between the two genera. However no alternative classification of Lavatera and Malva has commanded general acceptance, and the traditional division continues in use.
The Lavatera Pages covers species traditionally assigned to Lavatera, as species of Lavatera, as that is consistent with current horticultural practice, even though this may not be the correct placement for these species. A page on the Malva alliance discusses the correct classification for Lavatera and related genera.
Over 100 binominal names have been assigned to Lavatera, but the majority of these are invalid (see Synonymy of the Genus Lavatera), and there are 20-25 species, depending on the treatment of some geographical populations.
Cladograms based on a variety of flower and fruit characteristics, and RNA sequence comparisons, based on articles by M.F. Ray6, are shown below. The Pacific Lavateras include the 5 or 6 species from California and Australia. Of the other species not shown on the cladograms Lavatera mauritanica and abyssinica belong with the Malvoid group, and Lavatera oblongifolia, stenopetala and byronifolia with Lavatera thuringiaca and olbia.
A 1998 paper6 by M.F. Ray transfers the Pacific species, and Lavatera arborea, cretica, maritimaand acerifoliato Malva, on the basis of morphological and molecular evidence. He reports that on morphological evidence that Lavatera mauritanica should also be so transferred, but refrains from making a formal proposal in advance of confirmation by molecular evidence. Results from personal experiments with hybridisation also supports this placement of Lavatera mauritanica.
Kuntze (Feddes Repertorium 105(1-2): 7-18) proposed a classification of the sub tribe Malvinae of the Malveae in which the most, if not all, species of Lavatera were transferred to Althaea, and was followed in this by Borbas.
Assorted species of Lavatera have also been assigned to the genera Axolophaand Malva in the past.
Baker7 follows de Candolle in dividing the genus into four sections, Anthema, Axolopha, Olbia and Stegia, based on whether the flowers are borne in clusters or solitarily in the leaf axils. This division is followed in the Lavatera Pages, for the Lavatera Gallery, but with section Anthema extended to include all Ray's Malvoid species, i.e. the Tree Mallows and Pacific Lavateras. Elsewhere R. Fern proposed a section Glandulosae (whose contents are not known to me), and a section Lavatera has also been used, presumably including at least Lavatera trimestris. R. Fern also divided Lavatera into subgenera Lavatera and Navaea.
A number of alternative generic names have been proposed for parts of the traditional Lavatera. Navaea is a monotypic genus covering Lavatera phoenicea. As this is apparently the sister group to the remainder of Lavateraand Malva it may be acceptable to split this off as a separate genus under that name. The remaining non-Malvoid Lavateras have been assigned to the genera Stegia and Olbia. Stegia includes the single species Lavatera trimestris. However it seems to me that Stegia trimestris and its synonyms are invalid names, on the grounds that Lavatera trimestris is the type species of Lavatera.
The generic name Saviniona had earlier been proposed by Webb & Bertholet for Lavatera acerifolia, to which Greene added the Californian Lavateras. The Pacific Lavateras (the Californian Lavateras, plus the Australian Hollyhock, Lavatera plebeia) form a natural group, for which, if raised to generic rank, Saviniona would be the earliest published name, except that the type species Lavatera acerifolia is outside the group; Krebs proposed the name Viniosana for this group. The generic name Anthema has been applied to Lavatera arborea and cretica, but these two species do not appear to form a natural group.
The genus is named in honour of J.R. Lavater, a 16th century doctor and naturalist from Zurich, or jointly in honour of him and his brother.
Lavateras of the ×clementii group can readily be propagated from ripe or semi-ripe cuttings. No special treatment is required.
Lavatera trimestris is propagated by seed, which is widely available, sown in the spring.
Lavatera arborea is propagated by seed, sown in situ in late summer.
Seed of other species can also be obtained.
Lavateras of the ×clementii group may be pruned hard. Spring pruning is preferable; autumn pruning can result in the plants being badly affected by frost in winter (this is less of a risk in the mild British climate, but can happen; one winter a 'Barnsley' was nearly cut to the ground, and came back as a 'Rosea'). Otherwise prune as necessary to remove dead and wind-damaged material and revertant shoots, and to keep the shrub within bounds. Care should be taken not to overprune chimaerical cultivars such as 'Barnsley' or 'Chedglow', as this can lead to reversion.
Lavatera trimestris and Lavatera phoenicea have chromosome counts of 14, which is conjectured to be the basal chromosome count in Malvoideae. Lavatera mauritanica is a dodecaploid with a chromosome count of 84. Lavatera cretica has been reported to be hexadecaploid, with a chromosome count of 112, but this does not seem to be compatible with observations of fertile hybrids with Malva sylvestris; otherwise it is reported to be hexaploid, with a chromosome count of 42. Other recorded chromosome counts are close to the hexaploid number of 42; these include counts for Lavatera acerifolia (42), Lavatera arborea (40, 44), Lavatera assurgentiflora (ca 40), Lavatera cashmiriana (42, 44), Lavatera maritima (44), Lavatera oblongifolia (42), Lavatera occidentalis (ca 40), Lavatera olbia (42), Lavatera plebeia (43 (sic)), Lavatera punctata (40, 42), Lavatera thuringiaca (42), Lavatera triloba (42, 44) and Lavatera venosa (ca 40).
Photographs of various forms of Lavatera can be found on the web. A partial list follows. More links to photographs can be found on the pages for individual groups of Lavateras.
Lavatera arborea at Department of Botany, U of Catania
Lavatera arborea at Texas A&M University
Lavatera arborea at Universtiate de les Illes Balears
Lavatera arborea at Ruhr University at Bochum
Lavatera acerifolia at University of Graz
Lavatera ×clementii 'Barnsley Baby' at Future Plants
Lavatera cretica at Department of Botany, U of Catania
Lavatera 'Summer Kisses' at Future Plants
Lavatera 'Sweet Dreams' at Future Plants
Lavatera 'White Angel' at Future Plants
Lavatera 'White Satin' at Future Plants
Lavatera 'White Satin' at Hort.net Photo Gallery
Images from Google image search
Images in Wikimedia Commons
If you have found any errors on this page, or have any further information about the genus Lavatera then please contact me at email@example.com.
Malvaceae Info (Home)
© 1999-2010 Stewart Robert Hinsley