Kalanchoe (Crassulaceae) in Southern Africa: Classification, Biology, and Cultivation

By Gideon F. Smith, Estrela Figueiredo and Abraham E. van Wyk

Kalanchoe (Crassulaceae) in Southern Africa: Classification, Biology, and Cultivation provides a highly readable, illustrated account of the Kalanchoe species. The book includes an overview of the family Crassulaceae and genus Kalanchoe in global and subcontinental contexts that is followed by information on the taxonomic history of the genus. The characters and ecology of the species are also discussed, including their distribution ranges, where they occur, their habitat preferences, and where the species were formally recorded for the first time. For each indigenous and naturalized species, comprehensive taxonomic, descriptive and other information of interest is provided.

This is the must-have resource for plant scientists, plant taxonomists, ethnobotanists, herbarium curators, ecologists, pharmacologists, invasions scientists, horticulturalists and landscape designers.

• Includes currently accepted scientific names and synonyms, common names in English, morphology, cytology, chemistry, toxicology, biogeography, pollination biology, dispersal, cultivation, biocultural applications, and more
• Contains a dichotomous identification key and descriptions, providing much needed tools for accurate species identification
• Provides an extensive sets of illustrations for all species

• Language: English
• Publisher: Academic Press
• Release date: Oct 19, 2019
• ISBN: 9780128140086

Gideon F. Smith

Having authored or co-authored over 50 books, and hundreds of scientific and popular papers, Gideon F. Smith is South Africa’s most prolific author on succulents of the Old and New Worlds. He also has a keen interest in landscaping, gardens, and gardening. He is an Honorary Professor at the Nelson Mandela University, Port Elizabeth, South Africa, and a research associate at the University of Coimbra in Portugal.

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Chapter 1

Preface

Abstract

With about 1400 included species, the Crassulaceae is a large family with a near-cosmopolitan geographical distribution range. It is well known as consisting virtually exclusively of leaf succulents that inhabit some of the harshest natural environments on earth, ranging from low-rainfall deserts, to arctic snowscapes, to permanent or seasonal aquatic habitats. While several crassuloid genera have received considerable research attention over a broad spectrum of scientific botanical endeavour, interest in Kalanchoe has often focussed more narrowly on the importance of a selected few species, such as K. blossfeldiana, in the horti- and floricultural trades. Also, among collectors of succulent plants, representatives of the genus have not attained the same level of popularity as, for example, cacti, aloes, sedums, and haworthias. This applies especially to the African and Asian representatives of the genus. In contrast, the Madagascan species have received significantly more attention from an indoor and outdoor horticultural point of view, inter alia because a number of these species tend to become naturalised and ultimately weedy, in mild-climate regions, so drawing the attention of weed biologists. The focus in this work is on southern Africa, which is defined in this book as the Flora of Southern Africa region, which includes Namibia, Botswana, Swaziland, Lesotho, and South Africa. The classification, biology, and cultivation of Kalanchoe in the region are comprehensively treated.

Keywords:

About this book; Crassulaceae; Flora of Southern Africa region; Introductory explanation; Kalanchoe Adans.; Southern Africa; Taxonomic coverage

This book provides the first comprehensive, illustrated account for members of the succulent plant genus Kalanchoe Adans. in southern Africa. While several other genera of Crassulaceae in southern Africa have had books dedicated to them, the genus Kalanchoe has suffered some neglect. There are several possible reasons for this:

•With just less than 12% of the known global species diversity of Kalanchoe occurring in southern Africa, the genus is not as well represented in the subcontinent as other locally much more speciose crassuloid genera, such as the ubiquitous Crassula.

•When in bloom in autumn and winter, their clusters of small, tubular, cigar-shaped flowers are arguably not as eye-catching as the thickly flowered, brightly coloured candles and candelabras of other succulents such as aloes that more brightly lighten up the drab winter landscape.

•In some instances having opted for biennial or multiannual habits that often culminate in the plants that have flowered dying off, some kalanchoes tend to be comparatively short-lived, also in cultivation.

•Kalanchoes do not yet have a collective, locally well-known and widely used, descriptive common name that allows anyone to refer to them with ease, enabling informal communication about the plants by nonspecialists.

•Perhaps most importantly, the local species are absent from the high-density succulent plant areas in southern Africa, for example, the Klein Karoo, parts of the Groot Karoo, Knersvlakte, and Richtersveld.

Yet, in their typical bushveld (savanna) and grassland habitats, the smooth-edged or scallop-margined succulent leaves arranged in low-growing rosettes make kalanchoes striking and noticeable, and when they flower, their thin, often much-branched, or club-shaped to cylindrical, densely flowered inflorescences provide some respite from the otherwise muted-coloured autumn to late-winter landscapes. These waterwise plants are exceedingly tough and resilient; they thrive where they often grow under sparse or dense tree canopies (Fig. 1.1), interspersed among dense swathes of grasses, or survive in thin soils that settled in rock crevices on well-drained slopes.

Fig. 1.1 Kalanchoe crundallii is one of the rarest of the southern African kalanchoes. It is restricted to a few locations on the Soutpansberg in South Africa’s Limpopo province, where it invariably grows in the understory of dense bushveld in deep or dappled shade. Photograph: Gideon F. Smith.

Southern Africa, the main study area covered in this book, is here defined as comprising the countries Namibia, Botswana, Swaziland, Lesotho, and South Africa (see Fig. 1.2). Together, these countries comprise the so-called Flora of Southern Africa (FSA) region, which is abutted by the Conspectus florae angolensis region (Angola only) in the northwest, and the Flora zambesiaca region (Mozambique, Zimbabwe, Botswana, Zambia, and Malawi) in the centre and northeast. Note that Botswana is included in both the Flora of Southern Africa and Flora zambesiaca regions. Throughout the text, the part of Africa immediately north of the FSA region and south of the equator is referred to as south-tropical Africa.

Fig. 1.2 Map of the African continent south of 16°S, serving as a key to the maps used in this book. We cover those species of Kalanchoe indigenous to or cultivated/naturalised in southern Africa, a geographical region here defined as comprising Namibia, Botswana, Swaziland, Lesotho, and South Africa. The relief of the study area is shown in colour. Provincial boundaries and names are supplied for South Africa only. Bordering countries (Angola, Zambia, Zimbabwe, and Mozambique) are depicted with a grey relief and are broadly treated as part of south-tropical Africa. In the distribution maps supplied in this book, the ranges of indigenous (outlined in red) and naturalised (outlined in blue) species are shown with brighter relief colours, hence the additional bar of elevation colours in the map legend. In these maps, the ranges of only those indigenous species known to extend outside southern Africa are shown in the grey area, either as a red outline or with a red arrow indicating that a taxon is found further north in Africa or beyond. Note that the range maps depict probable and not definite distribution. We also do not map any of the species that are indigenous to south-tropical Africa but absent from the main study area, southern Africa.

This book includes overviews of the family Crassulaceae and the genus Kalanchoe in global and subcontinental contexts, followed by information on the taxonomic history of the genus in southern Africa, important collectors and researchers, kalanchoes in locally published botanical art, and the recorded common names of kalanchoes.

The characters and ecology of the species are discussed, including the distribution ranges where they occur, as well as whether they are widespread or range-restricted, for example, their habitat preferences, and from where the species were formally recorded for the first time, also mentioning type localities, which are in some cases well beyond the northern border of southern Africa.

The morphological characters and phenology, physiology and anatomy, biocultural significance and toxicity of southern African kalanchoes are also discussed. Uses of the southern African and some introduced kalanchoes in garden settings (Fig. 1.3), as well as the tendency of nonnative species to become invasive, are also noted, discussed, and illustrated.

Fig. 1.3 Some of the Madagascan kalanchoes that are commonly grown in gardens in southern Africa have escaped and become naturalised in the subcontinent; seven such species are included in this book. Here, the regular and white-leaved forms of Kalanchoe fedtschenkoi are cultivated together in a border in a garden in Pretoria, Gauteng, South Africa. Photograph: Gideon F. Smith.

For each of the indigenous, naturalised, garden-escape, and cultivated Kalanchoe species (Fig. 1.4), comprehensive nomenclatural, taxonomic, descriptive, and other information is provided, including maps of their geographical distribution ranges in southern Africa and slightly beyond. Detailed information is supplied on the type specimens of the species names—that is, those specimens that fix the application of the scientific names of the kalanchoes. All the naturalised and introduced, horticulturally popular Kalanchoe species in southern African are indigenous to Madagascar, the Red Island or Ile de Rouge, a major centre of present-day diversity for the genus.

Fig. 1.4 Potted specimens of Kalanchoe blossfeldiana , such as this one that belongs to the double-flowered Rosebud or Roseflower Group, are widely sold in nurseries and florist shops in southern Africa. In this book, we treat and discuss six noninvasive, exotic kalanchoes that are widely cultivated in the subcontinent. Photograph: Gideon F. Smith.

As part of an ongoing reassessment of the taxonomic status of southern African kalanchoes, we comprehensively investigated the infrageneric classification of the southern African kalanchoes and also provide, where it proved necessary, updates of the taxonomy of the locally naturalised, invasive, and cultivated kalanchoes. For the southern African species included in this work, we applied a cut-off date of 31 December 2016. All the southern African species that had been known on that date are treated in this book. Most names in Kalanchoe are burdened by many synonyms; these are discussed in detail to unambiguously establish the application of the names that should be applied to kalanchoes in southern Africa.

Figueiredo & Smith (2015) argued strongly for the typification of plant names, given that the application of names is determined by types. During the course of studies on Kalanchoe, it was necessary to typify several names that either lacked types or where previous typifications were not effective. This applies to the names of both indigenous southern African Kalanchoe taxa and to the Madagascan ones that have become locally naturalised. Correctly identifying and therefore naming species that are naturalised or even invasive are as important as documenting the indigenous diversity (Pyšek et al., 2013). The typifications made during the course of this study and several scientific papers that deal with the taxonomy of the Kalanchoe species included in this book were deliberately first published in the scientific literature; all the relevant papers are cited in this book. No new species are described here, and no new typifications are done.

Author citations of the names of the kalanchoes treated here are given in the ‘Contents’ page, as well as where the species are taxonomically treated in Chapter 12. In the rest of the text, author citations of the names are largely not given, except if there is a specific reason to do so. However, in the case of Kalanchoe species mentioned, but not treated in the taxonomic part of this book, either as accepted species or as synonyms, author citations are provided at their first reference in a chapter. For the format of author citations, we follow Brummitt & Powell (1992).

In the case of species and infraspecific names, the genus name Kalanchoe is spelled out when it is the first word in a sentence or at first mention in a paragraph, after which it is abbreviated to "K." However, to prevent confusion between, for example, Kalanchoe and Kitchingia Baker, which is at the genus rank a synonym of Kalanchoe, these genus names are at times spelled out in full throughout parts of the text. Kitchingia is the basionym of Kalanchoe subgen. Kitchingia (Baker) Gideon F.Sm. & Figueiredo.

Etymological information on people commemorated in the names of succulent plants, including kalanchoes, as well as the derivation of other specific epithets, is given in, among others, Korevaar et al. (1983) and Eggli & Newton (2004). However, in some instances, information that we sourced differed from that given in these references; we provide information on the origin of specific epithets where the species are treated in Chapter 12.

With very few exceptions, place names in South and southern Africa referenced in this book were standardised according to Raper et al. (2014), which elaborated on the earlier works of Raper (1987, 1989, 2004). Leistner & Morris (1976) was an additional invaluable resource for information on ¼-degree grids and place names in the subcontinent.

The conservation status we provide for all the indigenous southern African kalanchoes is based on natural history observations made during fieldwork over many years and following discussions with colleagues. Our suggested listings closely coincide with those given by the Red List of South African Plants (redlist.sanbi.org). We did not express an opinion on the conservation status of the species of Kalanchoe indigenous to Madagascar that are included in this book because of their local horticultural appeal only or invasiveness in southern Africa.

References☆

Brummitt R.K., Powell C.E. Authors of plant names. A list of authors of scientific names of plants, with recommended standard forms of their names, including abbreviations. Royal Botanic Gardens, Kew; 1992.

Eggli U., Newton L.E. Etymological dictionary of succulent plant names. Berlin: Springer-Verlag; 2004.

Figueiredo E., Smith G.F. Types to the rescue as technology taxes taxonomists, or the New Disappearance. Taxon. 2015;64:1017–1020.

Korevaar, L.C., van Donk, E., Peters, M., Deumer, P.V., Pullen, A.B., Smeenk, D.J., Theunissen, J., Waal, P.V.D., van Keppel, J.C., Uil, G.M., Noltee, F. & de Graaf, A. 1983. Wat betekent die naam. Een alfabetische lijst van botanischen namen van succulente en aanverwante planten met hun verklaring. Buining-fonds, Nederlands-Belgische vereniging van liefhebbers van cactussen en andere vetplanten, place of publication not stated.

Leistner, O.A. & Morris, J.W. 1976. Southern African place names. Annals of the Cape Provincial Museums 12: 1–565. Published jointly by the Cape Provincial Museums at the Albany Museum, Grahamstown.

Pyšek P., Hulme P.E., Meyerson L.A., Smith G.F., Boatwright J.S., Crouch N.R., Figueiredo E., Foxcroft L.C., Jarošík V., Richardson D.M., Suda J., Wilson J.R.U. Hitting the right target: Taxonomic challenges for, and of, plant invasions. AoB Plants. 2013;5:doi:10.1093/aobpla/042 plt042.

Raper P.E. Dictionary of southern African place names. Rivonia, Johannesburg: Lowry Publishers cc; 1987.

Raper P.E. (A) Dictionary of southern African place names. 2nd edition Parklands, Johannesburg: Jonathan Ball Publishers; 1989.

Raper P.E. New dictionary of South African place names. Jeppestown, Johannesburg: Jonathan Ball Publishers; 2004.

Raper P.E., Möller L.A., Du Plessis L.T. Dictionary of Southern African place names. Jeppestown, Johannesburg: Jonathan Ball Publishers; 2014.

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☆ To view the full reference list for the book, click here

Chapter 2

Crassulaceae of the World

Abstract

At present, about 1400 species that cover a vast array of growth forms are included in the family Crassulaceae. However, most species are shrubby or herbaceous perennials, with very few attaining treelike dimensions. Leaf succulence is common, with some species also displaying stem succulence. Most species show obvious traits associated with growing in xerophytic habits, but a few very widespread aquatic species are also known. The family is represented on most continents, especially in temperate and subtropical regions. To familiarise the reader with the genus-rank diversity in the Crassulaceae, a pictorial gallery of some non-southern African genera of the Crassulaceae is presented.

Keywords:

Crassulaceae; Global distribution; Natural habitats; Number of genera; Number of species; Visual guide to diversity in the family

Outline

Introduction

Genus and species diversity in, and distribution of, the Crassulaceae

Pictorial gallery of some genera of the Crassulaceae not indigenous to southern Africa, and of the closely related Saxifragaceae

Fig. 2.1 A naturalised specimen of Aeonium arboreum (L.) Webb & Berthel. growing at Cabo Sardão on the Alentejo coast, southwestern Portugal. Photograph taken on 29 December 2017 by Gideon F. Smith.

Introduction

Along with the Agavaceae (century plants), Aizoaceae (mesembs), Apocynaceae (carrion flowers), Asphodelaceae (aloes), and Cactaceae (cacti), the Crassulaceae (plakkies or stonecrops) are one of the best known succulent plant families globally. In terms of the number of species, it is the third largest family of succulent plants, after the mesembs and cacti. All the members of the Crassulaceae, even the few aquatic species, display leaf succulence, to a greater or lesser degree, and some are additionally stem succulents. Characters that define the Crassulaceae include:

•a comparatively primitive flower structure;

•regular, usually pentamerous flowers;

•isomerous flowers (having floral whorls with the same number of parts);

•free carpels; and

•a single or double whorl of stamens.

Apart from being predominantly leaf succulents, the Crassulaceae are further characterised by usually having small, star-shaped flowers borne in dense clusters. Most Crassulaceae species are shrubby, subshrubby, or low-growing, long-lived perennials or short-lived multiannuals. A few, such as Sedum mucizonia (Ortega) Raym.-Hamet from southwestern continental Europe (the Iberian Peninsula: Portugal and Spain), and northern Africa (Algeria and Morocco), are annuals, however, and are quick-growing, completing their vegetative and reproductive life cycles within a single growing season (Smith et al., 2016b). These annuals, also called therophytes, therefore survive unfavourable growing conditions in the form of seed that is often produced in great abundance. The majority of the world’s succulents are perennials, growing and flowering rather predictably year after year. The annual life form is fairly uncommon among succulents, given their ability to survive unfavourable growing conditions using, inter alia, moisture accumulated in their leaves, stems, or roots.

At the other end of the growth form spectrum, a very few representatives of the Crassulaceae become small trees; these are included in the predominantly southern African genera Tylecodon Toelken (one species) and Crassula L. (two species and one subspecies). In Crassula, only C. arborescens (Mill.) Willd. subsp. arborescens, C. arborescens subsp. undulatifolia Toelken, and C. ovata (Mill.) Druce have been accorded National Tree List numbers. The fourth southern African arborescent crassuloid taxon is Tylecodon paniculatus (L.f.) Toelken. The Mexican Sedum frutescens Rose with its thick stems and peeling bark has a similar vegetative appearance to and shows remarkable convergence with Crassula arborescens, C. ovata, and Tylecodon paniculatus (Smith et al., 2017c).

The circumscription of the Crassulaceae is reasonably stable, but as with most large families, in some instances, classification at genus and infrageneric ranks remains fluid. Over the past more or less 20–30 years, the Crassulaceae and several of its genera have been the subject of a number of phylogenetic studies and other genus- and family-level investigations (see, e.g. Eggli, 1987, 1988; Van Ham, 1994; Mes, 1995; Stevens, 1995; ʼt Hart & Eggli, 1995; and Gontcharova & Gontcharov, 2007, and references therein). The family studies showed that the Crassulaceae are a monophyletic unit that represents a ‘natural’ group. The Crassulaceae are mostly interpreted as closely related to the Saxifragaceae, a predominantly northern temperate group that also extends to subartic zones (Mabberley, 2017: 244; Harding, 1992; Köhlein, 1984; McGregor, 2008). The Penthoraceae either have been included in the Crassulaceae or in the Saxifragaceae (most often) or treated as a distinct family (Mabberley, 2017: 694).

Genus and species diversity in, and distribution of, the Crassulaceae

At present, about 1400 species are included in the family Crassulaceae, the most species-rich family in the order Saxifragales (Gontcharova & Gontcharov, 2007). This large diversity of species displays a bewildering range of growth forms, leaf shapes, and flower morphologies and colours. The species are arranged into between 35 and 45 genera that range in the number of included species from monotypic ones (one species only) such as Meterostachys to large ones with several hundred species, such as Sedum and Crassula. The number of genera recognised varies depending on the taxonomic concept followed, with several genera being segregates of, especially, Sedum. The genera often recognised in the Crassulaceae are summarised in Table 2.1.

Table 2.1

a Sedum here including Altamiranoa Rose ex Britton & Rose, Amerosedum Á.Löve & D.Löve, Ohbaea V.V.Byalt & I.V.Sokolova, Poenosedum Holub, and Sedastrum Rose.

bWe here regard Jovibarba Opiz as a genus distinct from Sempervivum L.

Phytogeographically, the Crassulaceae are widespread and occur on all the continents, mostly in warm and dry regions. They are often found in climatically harsh natural habitats that span a vast range, from seasonal to year-round aquatic pools to hot, fully exposed rocks, and the understory of deeply shaded forests and savannas. Some species are frost-hardy, while others grow best in the tropics and mild subtropics. With a global geographical distribution range that straddles the Old and New Worlds, the family Crassulaceae has a significant presence in continental North America, especially in Mexico, in Eurasia, and in sub-Saharan Africa, and in patches in South America but is underrepresented in Australia (Kapitany, 2007), South America, and Polynesia [a subregion of Oceania consisting of about 1000 islands] (Van Ham, 1994: 23).

In Europe, crassuloid species grow in low-lying, near-maritime niches on the Iberian Peninsula in the west (Smith & Figueiredo, 2013), to much higher elevations in the Caucasus, and eastern continental European countries such as Slovakia and the Czech Republic (Hadrava & Miklánek, 2007a, b), and further east, for example, in Siberia, where winter snow is a common occurrence (ʼt Hart & Eggli, 1995; Smith et al., 2015a). With the exception of the Sahara, the Crassulaceae occur virtually throughout the African continent, both south and north of this sandy desert, with a marked concentration of genera and species in southern Africa.

From a utilitarian economic point of view, the Crassulaceae are mostly important in the horticultural industry through the production, sometimes on an enormous scale, of material for outdoor cultivation in mild and even some continental-type climates (see, e.g. Horvath, 2014 on Sedum, and Walker, 2017 on Phedimus) and in harsher climates for the indoor-plant trade, through species such as Kalanchoe blossfeldiana, a typical windowsill plant. However, the Crassulaceae do not include any crop species.

Pictorial gallery of some genera of the Crassulaceae not indigenous to southern Africa, and of the closely related Saxifragaceae

Fig. 2.2 Aeonium balsamiferum Webb & Berthel., a Canary Islands endemic growing in the Shoenberg Temperate House in the Missouri Botanical Garden, St. Louis, USA. Photograph: Gideon F. Smith.

Fig. 2.3 Aeonium urbicum (C.Sm. ex Hornem.) Webb & Berthel. occurs in a wide area of Tenerife, Canary Islands. Photograph: Estrela Figueiredo.

Fig. 2.4 Dudleya farinosa Britton & Rose growing on coastal cliffs near San Francisco, California, USA. Photograph: Gideon F. Smith.

Fig. 2.5 Dudleya saxosa (M.E.Jones) Britton & Rose subsp. collomiae (Rose) Moran prefers rocky outcrops in central Arizona, USA. Photograph: Gideon F. Smith.

Fig. 2.6 Close-up of the flowers of Dudleya saxosa subsp. collomiae . Photograph: Gideon F. Smith.

Fig. 2.7 The leaves of Echeveria agavoides Lem. are often strongly red-margined. Photograph: Gideon F. Smith.

Fig. 2.8 Echeveria purpusorum A.Berger has an aloe-like, rosulate growth form. Photograph: Gideon F. Smith.

Fig. 2.9 Close-up of the bright orange and yellow flowers of Echeveria purpusorum . Photograph: Gideon F. Smith.

Fig. 2.10 Graptopetalum bartramii Britton & Rose subsp. arizonica (Rose) S.L.Welsh growing against a shady cliff in southern Arizona near Nogales, south of Tucson, USA. Photograph: Gideon F. Smith.

Fig. 2.11 Graptopetalum paraguayense (N.E.Br.) E.Walther carries small, compact rosettes at the ends of short, thin branches. Photograph: Gideon F. Smith.

Fig. 2.12 The flowers of Graptopetalum paraguayense are white with small red spots. Photograph: Gideon F. Smith.

Fig. 2.13 Hylotelephium cauticola (Praeger) H.Ohba occurs naturally in Japan. Photograph: Gideon F. Smith.

Fig. 2.14 Hylotelephium spectabile (Boreau) H.Ohba grown as a bedding plant in the garden of the Golden Phoenix Hotel, Beijing, China. Photograph taken on 25 July 2017 by Gideon F. Smith.

Fig. 2.15 Close-up of the pinkish white flowers of Hylotelephium spectabile . Photograph Gideon F. Smith.

Fig. 2.16 Jovibarba heuffelii (Schott) Á.Löve & D.Löve, a small, rosette-forming species from Eastern Europe, is sometimes treated as Sempervivum heufellii Schott. Photograph: Gideon F. Smith.

Fig. 2.17 Orostachys boehmeri (Makino) H.Hara is a small-growing, rosulate species from Japan. Photograph: Gideon F. Smith.

Fig. 2.18 Close-up of the spikelike inflorescence of Orostachys boehmeri . The flowers are white with prominently purplish red anthers. Photograph: Gideon F. Smith.

Fig. 2.19 Petrosedum forsterianum (Sm.) Grulich, here growing near Alvados in Portugal, has bright yellow flowers that are densely clustered together in forked but nevertheless often head-shaped inflorescences. Photograph: Estrela Figueiredo.

Fig. 2.20 The blue-leaved Petrosedum sediforme (Jacq.) Grulich growing near Alcanena in central Portugal. Photograph: Gideon F. Smith.

Fig. 2.21 Phedimus kamtschaticus (Fischer & C.A.Meyer) ʼt Hart has a very wide geographical distribution range in Russia, China, Japan, and Korea. Photograph: Gideon F. Smith.

Fig. 2.22 Phedimus spurius (M.Bieb.) ʼt Hart is native to the Caucasus, Iran, and Turkey. Photograph: Gideon F. Smith.

Fig. 2.23 Rhodiola integrifolia Raf., also sometimes regarded as Sedum integrifolium (Raf.) A.Nelson, occurs sympatrically with R. rhodantha (see Fig. 2.24) in a wetland in the Rocky Mountains above the treeline near Summit Lake along the Mount Evans road, about 100 km west of Denver, Colorado, USA. Photograph: Gideon F. Smith.

Fig. 2.24 Rhodiola rhodantha (A.Gray) H.Jacobsen, variously treated as Sedum rhodanthum A.Gray, or as Clementsia rhodantha (A.Gray) Rose ex Britton & Rose, growing in an ankle-deep, perennial wetland at an elevation of about 4000 m on Mount Evans, the highest summit of the Chicago Peaks in the Front Range of the Rocky Mountains, Colorado, USA. Photograph: Gideon F. Smith.

Fig. 2.25 The small Sedella pumila Britton & Rose, sometimes treated as Parvisedum pumilum (Benth.) R.T.Clausen, growing in a very moist habitat in the Hetch Hetchy Valley in California’s Yosemite National Park, USA. Photograph taken on 22 April 2011 by Estrela Figueiredo.

Fig. 2.26 The small, low-growing Sedum albertii Regel, sometimes treated as Pseudosedum affine (Schrenk) A.Berger, occurs in Siberia and Asia. Photograph: Gideon F. Smith.

Fig. 2.27 Sedum dasyphyllum L. is a small-leaved species from Europe. Photograph: Gideon F. Smith.

Fig. 2.28 The bright yellow-flowered Sedum lanceolatum Torr., sometimes treated as Amerosedum lanceolatum (Torr.) Á.Löve & D.Löve, growing in the Rocky Mountains, Colorado, USA. Photograph: Gideon F. Smith.

Fig. 2.29 One of the an annual species included in the genus, Sedum mucizonia (Ortega) Raym.-Hamet here grows against a vertical rock face along the Fórnea Trail near Alvados, central Portugal. Photograph: Estrela Figueiredo.

Fig. 2.30 Sedum pachyphyllum Rose, a Mexican species, has intensely red-tipped leaves. Photograph: Gideon F. Smith.

Fig. 2.31 The shrubby Sedum treleasei Rose is a native of Mexico. Photograph: Gideon F. Smith.

Fig. 2.32 Sempervivum arachnoideum L. has cobwebby rosettes. Photograph: Gideon F. Smith.

Fig. 2.33 Sempervivum tectorum L., the common houseleek of Europe. Photograph: Gideon F. Smith.

Fig. 2.34 Close-up of an inflorescence of Sempervivum tectorum . Photograph: Estrela Figueiredo.

Fig. 2.35 Umbilicus rupestris (Salisb.) Dandy growing on a rock wall near Serra de Santo António in the Parque Natural das Serras de Aire e Candeeiros in central Portugal. Photograph taken on 18 May 2015 by Gideon F. Smith.

Fig. 2.36 The family Saxifragaceae is often interpreted as a close relative of the Crassulaceae. The growth form of Saxifraga hostii Tausch subsp. rhaetica (Kerner) Br.-Blanq. is reminiscent of that of a number of crassuloid species. Photograph: Gideon F. Smith.

Fig. 2.37 Close-up of the small, white flowers of Saxifraga hostii subsp. rhaetica . Photograph: Gideon F. Smith.

Fig. 2.38 The low-growing Saxifraga paniculata Mill. carries its flowers in densely clustered inflorescences. Photograph: Gideon F. Smith.

Fig. 2.39 The leaves of Saxifraga rotundifolia L. are reminiscent of those of Umbilicus rupestris (Salisb.) Dandy, the navelwort, which is a member of the Crassulaceae. Photograph: Gideon F. Smith.

Fig. 2.40 Saxifraga stolonifera Curtis is a popular house plant and arguably the best known of the Saxifraga species. The open rosettes produce numerous, long runners at the ends of which plantlets are formed. The small, red-spotted, white flowers are zygomorphic, but nonetheless reminiscent of those of some representatives of the Crassulaceae. Photograph: Gideon F. Smith.

References☆

Eggli U. Neue Taxa der Gattung Rosularia (De Candolle) Stapf (Crassulaceae—Sedoideae). Kakteen und andere Sukkulenten. 1987;38:134–138.

Eggli U. A monographic study of the genus Rosularia (Crassulaceae). Bradleya. 1988;6(Supplement):1–119.

Eggli U., ed. Illustrated handbook of succulent plants: Crassulaceae. Berlin: Springer-Verlag; 2003.

Gontcharova S.B., Gontcharov A.A. Molecular phylogenetics of Crassulaceae. Genes, Genomes and Genomics. 2007;1(1):40–46.

Hadrava, J. & Miklánek, M., 2007a. The Czech houseleeks. The genus Sempervivum L. Kaktusy XXXXIII. Special 1, 7–20, 35.

Hadrava, J. & Miklánek, M., 2007b. The Czech houseleeks. The genus Jovibarba Opiz. Kaktusy XXXXIII. Special 1, 21–35.

Harding W. Saxifrages. A gardener’s guide to the genus. Avonbank, Pershore, Worcestershire: The Alpine Garden Society; 1992.

Horvath B. The plant lover’s guide to sedums. Portland, Oregon, and London: Timber Press; 2014.

Kapitany, A., 2007. Australian succulent plants. An introduction. Kapitany Concepts, Boronia, Victoria, Australia.

Köhlein F. Saxifrages and related genera. London: B.T. Batsford Ltd; 1984.

Mabberley, D.J., 2017. Mabberley’s plant-book. A portable dictionary of plants, their classification and uses utilizing Kubitzki’s The families and genera of vascular plants (1990– ) and current botanical literature; arranged according to the principles of molecular systematics. 4th edition, completely revised, with some 1400 additional entries. Cambridge University Press, Cambridge, United Kingdom.

McGregor M. Saxifrages. A definitive guide to the 2000 species, hybrids & cultivars. Portland, Oregon: Timber Press; 2008.

Mes, T.H.M., 1995. Origin and evolution of the Macaronesian Sempervivoideae (Crassulaceae). PhD dissertation (Proefschrift), Faculteit Biologie, Universiteit Utrecht, Utrecht, The Netherlands, pp. 1–215.

Rowley G.D. The illustrated encyclopedia of succulents. A guide to the natural history and cultivation of cacti and cactus-like plants. A Salamander Book. 1978 Published by Leisure Books, place of publication not stated.

Smith G.F., Figueiredo E. The family Crassulaceae in continental Portugal. Bradleya. 2013;31:76–88.

Smith G.F., Figueiredo E., Mort M.E. Taxonomy of the three arborescent crassulas, Crassula arborescens (Mill.) Willd. subsp. arborescens, C. arborescens subsp. undulatifolia Toelken, and Crassula ovata (Mill.) Druce (Crassulaceae) from southern Africa. Bradleya. 2017c;35:87–105.

Smith G.F., Figueiredo E., Silva V. Geographical distribution range extension for Sedum acre L. (Crassulaceae) in central Portugal. Bradleya. 2015a;33:34–40.

Smith G.F., Figueiredo E., Silva V. Notes on the geographical distribution range of Sedum mucizonia (Ortega) Raym.-Hamet (Crassulaceae), a miniature, annual succulent, in continental Portugal. Bradleya. 2016b;34:133–141.

Stevens, J.F., 1995. The systematic and evolutionary significance of phytochemical variation in the Eurasian Sedoideae and Sempervivoideae (Crassulaceae). PhD dissertation (Proefschrift), in de Wiskunde en Natuurwetenschappen, Rijksuniversiteit Groningen, The Netherlands, pp. 1–210.

ʼt Hart and Eggli, 1995 ʼt Hart H., Eggli U., eds. Evolution and systematics of the Crassulaceae. Leiden: Backhuys Publishers; 1995.

Thiede J., Eggli U. Crassulaceae. In: K. Kubitzki, ed. The families and genera of vascular plants. IX. Flowering Plants. Eudicots. Berlin: Springer-Verlag; 2007:83–118.

Van Ham, R.C.H.J., 1994. Phylogenetic implications of chloroplast DNA variation in the Crassulaceae. PhD dissertation (Proefschrift), Faculteit Biologie, Universiteit Utrecht, Utrecht, The Netherlands, pp. 1–153.

Walker C.C. Introducing the genus Phedimus. New Zealand Cactus and Succulent Journal. 2017;70(2):4–7.

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Chapter 3

Crassulaceae in Southern Africa

Abstract

Although the family Crassulaceae has a very wide global distribution range, the family has definite areas of high present-day species diversity. These include the southern Africa subcontinent, Mexico, and parts of southwestern North America, Mediterranean Europe, and parts of the Orient. Five of the c. 34 genera recognised in the Crassulaceae are represented naturally in southern Africa. These genera, Adromischus Lem., Cotyledon L., Crassula L., Kalanchoe Adans., and Tylecodon Toelken, are illustrated and briefly discussed with reference to their diversity and distribution ranges in the subcontinent and beyond. To familiarise the reader with the genus-rank diversity in southern African Crassulaceae, a pictorial gallery of southern African genera, excluding Kalanchoe, in the family is presented.

Keywords

Adromischus Lem.; Cotyledon L.; Crassula L.; Crassulaceae; Kalanchoe Adans.; Number of genera; Natural habitats; Number of species; Southern Africa; Subcontinental geographical distribution range; Tylecodon Toelken

Outline

Introduction

Brief summary of the genera

1. Crassulaceae subfam. Crassuloideae

1.1 Crassula L., Sp. pl. 1: 282 (1753)

2. Crassulaceae subfam. Kalanchooideae

2.1 Adromischus Lem., Jard. Fleur. 2, Misc. 59 (1852)

2.2 Cotyledon L., Sp. pl. 1: 429 (1753)

2.3 Kalanchoe Adans., Fam. pl. 2: 248 (1763)

2.4 Tylecodon Toelken in Bothalia 12: 378 (1978)

Introduction

In southern Africa, the Crassulaceae are represented by five of the c. 34 genera (Thiede & Eggli, 2007) recognised in the family. Therefore, about 15% of the crassuloid genera occur in the region (see Meyer et al., 1997: 69 and Smith et al., 1997: 56–63). These are: (1.) Adromischus Lem.; (2.) Cotyledon L.; (3.) Crassula L.; (4.) Kalanchoe Adans.; and (5.) Tylecodon Toelken (see Table 3.1). Two of these genera (Adromischus and Tylecodon) are endemic to the region, while the vast majority of the species of Cotyledon and Crassula occur in southern Africa. In contrast, just over 10% of the known species of Kalanchoe occur in southern Africa.

Table 3.1