Neotropical Malvaceae (Byttnerioideae)

Bente B. Klitgård

Royal Botanic Gardens, Kew, U.K.

Description

Malvaceae s.l.

Habit: shrubs, trees (herbs).  Leaves alternate or two-ranked, stipulate; leaf margin toothed or entire; venation palmate or 3-nerved.  Inflorescences made up of cymose units (bicolor units, named after Theobroma bicolor where it was first observed).  Flowers with epicalyx present or absent; sepal aestivation valvate; androgynophore present or absent; stamens 5-many, in five groups (fundamentally obdiplostemonous).  Fruit a capsule, berry, schizocarp.

Subfamily Byttnerioideae (Byttneriaceae)

Habit: usually small shrubs, less often trees, lianas or herbs; bark highly fibrousLeaves alternate or two-ranked; simple, rarely palmate (Herrania); venation palmate or 3-nerved, margins often serrate; stipules present, often falling early; indumentum, if present, stellateInflorescences axillary, leaf-opposed or rarely terminal thyrses, sometimes reduced to solitary flowers or cauliflorous fascicles (Theobroma and Herrania).  Flowers bisexual, actinomorphic; epicalyx usually absent; calyx of 5 sepals fused for less than ½ their length; corolla of 5 free petals, these often cupped or hooded and with a strap-like appendage, basally free from the androecium, sometimes completely reduced (species of Hermannia, Melochia, Waltheria); androgynophore absent; stamens 5 to 10, rarely more, fused into short tube or fascicles, anthers usually dithecal, rarely trithecal; ovary superior, (1-3)5-locular; style simpleFruit a many-seeded, indehiscent, fleshy berry, dehiscent capsule or schizocarp with 1-many-seeded mericarps.  Seeds usually glabrous, sometimes arillate or pubescent.

Notes on delimitation

The past 15 years have seen an explosion in the number of phylogenetic and taxonomic studies of the core Malvales clade (e.g. La Duke & Doebley 1995; Alverson et al. 1998, 1999; Bayer et al. 1999; Baum et al. 2004; Nyffeler et al. 2005; Pfeil et al. 2005; García et al. 2009).  These studies tackle the arbitrary and inconsistent delimitations among the families previously recognised within the clade.  Recent outcomes of these papers include two reclassifications of the clade.  One is by Bayer & Kubitzki (2002), who subsumed the previously recognized families Bombacaceae, Brownlowiaceae, Byttneriaceae, Dombeyaceae, Grewiaceae (~ more or less Sparrmanniaceae), Helicteraceae (~ more or less Durionaceae), Malvaceae s.s., Pentapetaceae, Sterculiaceae and Tiliaceae as subfamilies under Malvaceae s.l.  The other is by Cheek (2007) who recognised ten families inside the core Malvaceae clade.  The APG III system (2011) adopted the subfamily approach which is also followed in this treatment.  In Latin America there are representatives of the following Malvaceae subfamilies:  Bombacoideae, Brownlowioideae, Byttnerioideae, Grewioideae, Helicteroideae, Malvoideae, Sterculioideae, and Tilioideae.  The infrafamiliar classification adopted here follows that of Bayer & Kubitzki (2002).

Byttnerioideae (alternatively Byttneriaceae):  its members were formerly included in the Sterculiaceae, but molecular, morphological (presence of cupped petals and absence of androgynophore) and biogeographic data joined these genera and resolved Grewioideae as its sister, thus separating them from the reduced Sterculiaceae/Sterculioideae.

Distribution in the Neotropics

The family Malvaceae s.l. includes 243 genera and about 4,225 species which are largely tropical and temperate.  Of these 129 genera and 1,900-2,200 are native to the Neotropics. 

Subfamily Byttnerioideae is pan- and subtropical and consists of 27 genera and c. 650 species; widely distributed in Africa and Latin America with eight genera and 280-300 species in the Neotropics.  About half the genera are restricted to Australasia.  Some groups are mainly found in humid tropical forest, while others are restricted to drier habitats.

  • Ayenia L.:  about 70 species from southern North America to Argentina.
  • Byttneria Loefl.:  pantropical with more than 130 species, about 80 of which are neotropical.
  • Guazuma Mill.:  three species from Mexico to NE Argentina and West Indies.
  • Herrania Goudot:  about 17 species in tropical Central and South America.
  • Hermannia L.:  More than 100 spp., majority in the Old World (South Africa, Madagascar, Australia), four spp. in southern North America and adjacent Mexico (H. inflata Link & Otto, H. palmeri Vasey & Rose, H. pauciflora S. Watson, and H. texana A. Gray)
  • Melochia L.:  less than 50 species, mostly neotropical, a few in the Palaeotropics - some widely distributed weeds (Chocolate weed - M. corchorifolia L).
  • Rayleya Cristóbal:  one species (R. bahiensis Cristóbal) from Brazil.
  • Theobroma L.:  22 species - in tropical rain forests of Central and South America.
  • Waltheria L.:  about 50 to 60 species, mostly neotropical with centres of diversity in Mexico and Brazil (W. indica L. native to the New World, but a pantropical weed).

Distinguishing characters (always present)

Other important characters

  • Usually small shrubs, less often trees, lianas or herbs.
  • Indumentum, if present, usually of stellate, rarely lepidote trichomes.
  • Stamens antepetalous, 5-10, solitary or in groups of 2-3(-6) with the filaments fused within groups.
  • Fruit a berry, capsule, rarely schizocarp.

Key differences from similar families

The families and subfamilies listed below differ from the Malvaceae subfamily Byttnerioideae as follows:

  • Brownlowioideae - sepals fused into a campanulate or urceolate tube; stamens many, free or fasciculate.
  • Bombacoideae - usually stout trees with bottle-shaped and/or trunks armed with prickles; leaves usually palmate/palmately lobed; sepals fused into a tube; petals adnate to androecium; style branched.
  • Cochlospermaceae - anthers dehisce via pores.
  • Grewioideae - petals usually yellow or white, clawed, often with hairy basal nectaries; stamens numerous, free, sometimes grouped in antesepalous fascicles.
  • Helicteroideae - calyx tubular; epicalyx always present; petals clawed; androgynophore usually present; stamens 10-30; ovaries usually apocarpous, except Ungeria and Reevesia.
  • Malvoideae - epicalyx is present in ½ and absent in ½ the Neotropical genera; petals adnate to the androecium; stamens fused into a staminal column.
  • Sterculioideae - petals always absent; androgynophore usually present; stamen filaments free; ovaries apocarpous.

Useful tips for generic identification

Key to genera of Neotropical Malvaceae-Byttnerioideae (modified from Bayer & Kubitzki, 2003)

1.  Stamens usually more numerous than sepals … 2
1.  Stamens usually as many as sepals … 4

2.  Petal appendages bifid; staminodes short … Guazuma
2.  Petal appendages entire; staminodes prominent … 3

3.  Leaves digitately compound; trees without plagiotropic side branches … Herrania
3.  Leaves simple or rarely lobed; trees with plagiotropic side branches … Theobroma

4.  Staminodes absent or rudimentary, never lianas, usually shrubs or herbs, rarely trees … 5
4.  Staminodes present, never herbs, usually shrubs or lianas, rarely trees … 6

5.  Ovary 5-locular … 6
5.  Ovary 1-locular … Waltheria

6.  Carpels antepetalous; ovarial locules usually with 2 ascending ovules … Melochia
6.  Carples aneepalous; ovarial locules with several more or less horizontal loculesHermannia

7.  Anthers trithecal, androgynophore present, usually long and prominentAyenia
7.  Anthers dithecal, androgynophore usually absent, rarely present …8

8.  Shoots often spinose; androgynophore absent … Byttneria (throughout Latin America)
8.  Shoots not spinose; androgynophore prominentRayleya (Bahia, Brazil)

Status

Native.

General notes

  • Herrania lemniscata (Schomb.) R.E.Schult. the sweet-sour pulp around the seeds is edible, tasting similar to Theobroma pulp (Millken & Albert 1999).
  • Theobroma cacao and relatives are used to make chocolate.  Chocolate is more than just a delicacy: evidence suggests that eating between 46 and 105g of chocolate a day can have a moderate effect on lowering blood pressure (Ried et al. 2012).
  • Cocoa has also been used for an array of medicinal purposes. Unfermented cocoa seeds and the seed coat are used to treat a variety of ailments, including diabetes, digestive and chest complaints. Cocoa powder, prepared from fermented cocoa beans, is used to prevent heart disease. Cocoa butter is taken to lower cholesterol levels, although its efficacy is unclear.  It is also used widely in foods and pharmaceutical preparations, as well as being used as a rich moisturiser for the skin.
  • The crushed shells of cocoa beans are used as an alternative to peat mulch. Mulches are layered on to the soil surface to suppress weeds, conserve moisture, improve its visual appearance and minimize erosion. Not only does this make good use of cocoa-shell, which is a by-product of the chocolate industry, but it also helps reduce the use of peat.
  • For further information see http://www.kew.org/plants-fungi/Theobroma-cacao.htm.

Important literature

Alverson, W.S., Karol, K.G., Baum, D.A., Chase, M.W., Swensen, S.M., McCourt, R. & Systma, K.J. 1998.  Circumscription of the Malvales and relationships to other Rosidae: Evidence from rbcL sequence data. American J. Bot. 85: 876-887.

Alverson, W.S., Whitlock, B.A., Nyffeler, R., Bayer, C. & Baum, D.A. 1999.  Phylogeny of core Malvales: Evidence from ndhF sequence data. American J. Bot. 86: 1474-1486.

Baum, D.A., Smith, S.D., Yen, A., Alverson, W.S., Nyffeler, R., Whitlock, B.A., & Oldham, R.L. 2004.  Phylogenetic relationships of Malvatheca (Bombacoideae and Malvoideae; Malvaceae sensu lato) as inferred from plastid DNA sequences. American J. Bot. 91: 1863-1871.

Bayer, C. 1999.  The bicolor unit - homology and transformation of an inflorescence structure unique to core Malvales. Plant Syst. Evol. 214: 187-198.

Bayer, C., Fay, M.F., Bruijn, A.Y. de, Savolainen, V., Morton, C.M., Kubitzki, K., Alverson, W.S. & Chase, M.W. 1999.  Support for an expanded family concept of Malvaceae within a recircumscribed order Malvales: a combined analusis of plastid atpB and rbcL DNA sequences.  Botanical Journal of the Linnean Society 129: 267-303.

Bayer, C. & Kubitzki, K. 2002.  Malvaceae, Byttnerioideae. In: K. Kubitzki, & C. Bayer (eds). The Families and Genera of Vascular Plants vol. V, pp. 241-247. Springer-Verlag, Berlin.

Bornstein, A.J. 1989. Sterculiaceae. In: Howard, R.A. (ed.). Flora of the Lesser Antilles: Leeward and Windward vol. 5, pp. 272-292. Jamaica Plain, Arnold Arboretum, Harvard University.

Bovini, M.G., Esteves, G. & Duarte, M.C. 2010. Malvaceae. In: Forzza, R.C. et al. (eds.). Catálogo de Plantas e Fungos do Brasil, pp. 1201-1227. Institúto de Pesquisas Jardím Botânico do Rio de Janeiro, Rio de Janeiro.

Cheek, M.R. 2007.  Byttneriaceae, p. 76. In: V.H. Heywood, R.K. Brummitt, A. Culham, & 0. Seberg (eds). Flowering Plant Families of the World, pp. 241-247. Royal Botanic Gardens, Kew.

Cristóbal, C.L. 1960.  Revisión del género "Ayenia". Opera Lilloana 4: 1-230.

Cristóbal, C.L. 1976.  Estudio taxonomico del genero Byttneria Loefling (Sterculiaceae).  Bonplandia 4: 3-428.

Cristóbal, C.L. 1981.  Rayleya, nueva Sterculiaceae de Bahia - Brasil. Bonplandia 5: 43-50.

Cristobal, C.L. 1998. Sterculiaceae fam. 178.  In: Hunziker, A.T. (ed.).  Flora fanerogamica Argentina.  Fasciculo 57, 32pp.  Proflora, Cordoba.

Cristóbal, C.L. 2001.  Sterculiaceae. In: Stevens, W.D., Ulloa U., C., Pool, A. & Montiel, O.M. (eds.). Flora de Nicaragua tomo III, pp. 2428-2437. Monographs in Systematic Botany from the Missouri Botanical Garden vol. 85.  St. Louis.

Cristóbal, C.L. 2007.  Sterculiaceae de Paraguay, I.  Ayenia, Byttneria, Guazuma, Helicteres, Melochia y Sterculia. Bonplandia 16(1-2): 5-142.

Cristóbal, C.L., Saunders, J.G., & Berry, P.E. 2005.  Sterculiaceae.  In: Berry, P.E., Holst, B.K. & Yatskievych, K. (eds.).  Flora of the Venezuelan Guyana vol. 9, pp. 248-280.  Missouri Botanical Garden, St. Louis.

Cristóbal, C.L. & Saunders, J.G. 2008.  Sterculiaceae. In: Zuloaga, F.O., Morrone, O. & Belgrano, M.J. (eds.). Catálogo de las Plantas Vasculares del Cono Sur vol. 3, pp. 3055-3064. Missouri Botanical Garden Press, St. Louis.

Door, L.J. 2002.  Sterculiaceae. In: S.A. Mori, G. Cremers, C.A. Gracie, J.-J. de Granville, S.V. Heald, M. Hoff & J.D. Mitchell (eds.). Guide to the Vascular Plants of Central French Guiana, pp. 700-706.  Memoirs of the New York Botanical Garden 76, part 2.  New York Botanical Garden Press.

Door, L.J. & Fryxell, P.A. 1999.  Sterculiaceae. In: Jørgensen, P.M. & León-Yánez, S. (eds.). Catalogue of the Vascular Plants of Ecuador, pp. 918-922. Missouri Botanical Garden Press, St. Louis.

Fryxell, P.A. 2004.  Sterculiaceae. In: N. Smith, S.A. Mori, A. Henderson D.W. Stevenson & S.V. Heald (eds). Flowering Plants of the Neotropics, pp. 360-362. Princeton University Press, Princeton.

García, P.E., Schönswetter, P., Aguilar, J.F., Feliner, G.N., & Schneeweiss, G.M. 2009.  Five molecular markers reveal extensive morphological homoplasy and reticulate evolution in the Malva alliance (Malvaceae). Mol. Phyl. Evol. 50: 226-239.

Goldberg, A. 1967.  The genus Melochia (Sterculiaceae). Contr. U.S. Nat. Herb. 34(5): 191-363.

Hinsley, S.R. 2013.  MALVACEAE info.  http://www.malvaceae.info/index.html (accessed 17/01/2013)

Klitgård, B.B., Grace, O. & Tredwell, E. (2010 onwards).  Theobroma cacao (cocoa tree) - species page. http://www.kew.org/plants-fungi/Theobroma-cacao.htm

La Duke, J.C. & Doebley, J. 1995.  A chloroplast DNA based phylogeny of the Malvaceae. Systematic Botany 20: 259-271.

Merello, M.C., Cristóbal, C.L. & Dorr, L.J. 1993. Sterculiaceae. In: Brako, L. & Zarucchi, J.L. (eds.). Catalogue of the Flowering Plants and Gymnosperms of Peru, pp. 1137-1142. Monographs in Systematic Botany from the Missouri Botanical Garden vol. 45. St. Louis.

Milliken, W. & Albert, B. 1999.  Yanomami: A Forest People. Royal Botanic Gardens, Kew.

Nyffeler, R., Bayer, S., Alverson, S.A., Yen, A., Whitlock, B.A., Chase, M.W., Baum, D.A. 2005.  Phylogenetic analysis of the Malvadendrina clade (Malvaceae s.l.) based on plastid DNA sequences.  Organisms, Diversity & Evolution 5: 109-123.

Pfeil, B.E. & Crisp, M.D. 2005.  What to do with Hibiscus? A proposed nomenclatural resolution for a large and well known genus of Malvaceae and comments on paraphyly. Australian Syst. Bot. 18: 49-60.

Ried K, Sullivan TR, Fakler P, Frank OR, Stocks NP. 2012. Effect of cocoa on blood pressure. Cochrane Database of Systematic Reviews Issue 8. Art. No.: CD008893. DOI: 10.1002/14651858.CD008893.pub2.

Rose, J.N. 1897.  A Synopsis of the American Species of Hermannia. Contrib. US National Herbarium 5(3): 130-131.

Ruiz, E. 2005.  Sterculiaceae. In: Marticorena, C. & Rodrígues, R. (eds.). Flora de Chile vol. 2(3), pp. 20-21. Universidad de Concepción, Concepción.

Robyns, A. & Cuatrecasas. 1964.  Sterculiaceae, family 117. In: Woodson, R.E. & Schery, R.W. (eds.) Flora of Panama part VI. Ann. Missouri Bot. Gard. 51: 69-107.

Rondon, J.B., Cumana C., L.J. 2005.  Revision taxonomica del genero Theobroma (Sterculiaceae) en Venezuela.  Acta Bot. Venezuel. 28: 113-133.

Saunders, J.G. 1993.  Four new distylous species of Waltheria (Sterculiaceae) and a key to the Mexican and Central American species and species groups. Syst. Bot. 18: 356-376.

Saunders, J.G. 1995.  Systematics and Evolution of Waltheria (Sterculiaceae-Hermannieae). Ph.D. diss. The University of Texas at Austin. 854 pp.

Saunders, J. G. 2005. New species of Waltheria (Hermannieae, Byttnerioideae, Malvaceae) from Paraguay, Argentina, and Venezuela, and two new records for Paraguay. Darwiniana 43(1-4): 201-211.

Silva, C.R.S. & Figueira, A. 2005.  Phylogenetic analysis of Theobroma (Sterculiaceae) based on Kunitz like trypsin inhibitor sequences.  Plant Systematics & Evolution 250: 93-104.

Stevens, P. F. (2001 onwards).  Angiosperm Phylogeny Website. Version 9, June 2008 (visited 6th Feb. 2013). http://www.mobot.org/MOBOT/research/APweb/.

Whitlock, B.A. & Baum, D.A. 1999.  Phylogenetic relationships of Theobroma and Herrania (Sterculiaceae) based on sequences of the nuclear gene vicilin. Systematic Botany 24(2): 12-138.

Whitlock, B.A., Bayer, C. & Baum, D.A. 2001.  Phylogenetic Relationships and Floral Evolution of the Byttnerioideae ("Sterculiaceae" or Malvaceae s.l.) Based on Sequences of the chloroplast Gene, ndhF. Systematic Botany 26(2): 420-437.

Whitlock, B.A. & Hale, A.M. 2011.  The Phylogeny of Ayenia, Byttneria, and Rayleya (Malvaceae s.l.) and Its Implications for the Evolution of Growth Forms. Systematic Botany 36(1): 129-136.

How to cite

Klitgård, B.B. (2013). Neotropical Malvaceae (Byttnerioideae). In: Milliken, W., Klitgård, B. & Baracat, A. (2009 onwards), Neotropikey - Interactive key and information resources for flowering plants of the Neotropics. http://www.kew.org/science/tropamerica/neotropikey/families/Malvaceae_(Byttnerioideae).htm.