Melochia, Linnaeus, 1753

Gonçalez, Victor Martins & Esteves, Gerleni Lopes, 2015, Synopsis of Melochia L. (Byttnerioideae, Malvaceae) in southeastern Brazil, Phytotaxa 226 (3), pp. 217-232 : 219-220

Section Melochia L.

Characterization and distribution. Cymes axillary and/or terminal or at the apex of small axillary branches; calyx campanulate to cupuliform; variable petal color, with or without a basal spot; longistylous form of the stemens completely concrescent in a tube; capsule globose, rostrate, apterous, stipe present or absent, capsule loculicidal through the dorsal and ventral suture, and completely septicidal, stigma persistent or deciduous; seed reticulate.

Comprises approximately 11 species distributed from the United States through Central America, to the Antilles and Argentina. Eight species occur in Brazil ( Goldberg 1967). Five species are recorded for the Brazilian Southeast Region.

Melochia arenosa Bentham (1842: 127) . Type :— GUYANA, “Sandy banks of the Essequibo and Rupunoony [Rupununi]” Schomburgk 31 (lectotype E, here designated; photo E!).

Figs. 3I–K , 4A .

Distribution and habitat:— Cuba, Venezuela to Paraguay. In Brazil this species occurs in the states of: Acre, Amazônas, Pará, Piauí, Mato Grosso, Minas Gerais, São Paulo, and Paraná. It inhabits partially flooded and humid areas of Amazon Rain Forest, Pantanal, Cerrado and Atlantic Rain Forest. This is the first record of M. arenosa for São Paulo state. Flowering and fruiting occurs from April to November.

Specimens examined:— BRAZIL. Minas Gerais: Araxá , 01 April 1993, M. Brandão 22504 ( PAMG) ; Buritizeiro , 09 June 1990, G. Hatschbach et al. 54147 ( MBM) ; 14 November 2011, V. M. Gonçalez et al. 112 ( SP) ; 03 April 1992, G. Hatschbach et al. 56497 ( MBM) ; Pompéu , 09 September 2000, J. L. Silva s.n. ( SP, OUPR 9825 ) ; Santana do Riacho , 27 January 1990, R. Simão-Bianchini CFSC 11687 ( SP, SPF) ; São Romão , 20 April 1992, E. Tameirão Neto 686 ( BHCB) . São Paulo: Promissão , 20 June 1939, G. Hashimoto 124 ( SP) .

Melochia arenosa is readily distinguished from other species with globose fruits, by a dense indumentum constituted of very small, multiradiate trichomes with 8–20 rays of about 1 mm long, forming tufts on branches and leaves. Other distinctive morphological characters are the cinereous abaxial surface of the leaves, the curved bracts and the shortly serrate leaf margins.

After analyzing the protologue and the syntypes, Schomburgk 31 was chosen as a lectotype by its precise conformity to the morphological description of the species.

Conservation status:— Vulnerable ( IUCN 2011). Registered known to exist at no more than ten localities. Additionally, populations are very small, or consist of isolated individuals.

Melochia simplex Saint-Hilaire (1825: 164) . Type:— BRAZIL, São Paulo, near Guaratinguetá, A. Saint-Hilaire cat. 756d (isotype P, cited by Goldberg, 1967).

Figs. 4B , 5C .

Distribution and habitat:— Guyana, Bolivia, Paraguay, Brazil and northern Argentina. In Brazil this species occurs in the states of: Amazônia, Goiás, Mato Grosso, Minas Gerais, São Paulo, Paraná and Rio Grande do Sul. It inhabits dry and humid fields or marshes in Amazon Rain Forest, Cerrado and Atlantic Rain Forest. Flowering and fruiting occur from November to April.

Specimens examined:— BRAZIL. Minas Gerais: Carmo do Rio Claro , 08 September 1961, A. G. Andrade & M. Emmerich 1149 ( R) ; Ituiutaba , 04 April 1950, A. Macedo s.n. ( SP 68852 ) . São Paulo: Aguaí , 21 January 1997, A. D. Faria et al. 97/169 ( SP) ; Atibaia, 24 October 1960, G. Eiten & L. T. Eiten 2404 ( SP) ; Embu , 10 December 2009, R. T. Shirasuna 2674 ( PMSP, SP) ; Luiz Antonio , 24 February 1998, S. A. Nicolau et al. 2456 ( SP) ; Mooca , January 1913, A. C. Brade 5973 ( SP) ; s.l., s.d., Sellow 5288 ( R) .

The is a new species record to Minas Gerais State.

Amidst the species of the section Melochia , M. simplex is easily recognized by its linear to narrow-elliptic leaves, and serrate leaf margins with closely spaced irregular teeth.

Conservation status:— Vulnerable ( IUCN 2011). Registered known to exist at no more than ten localities, and not found in conservation areas. Additionally, populations are very small, or consist of isolated individuals.

Melochia graminifolia Saint-Hilaire (1825: 160) . Type:— BRAZIL, Minas Gerais, Minas Novas, S. Domingos, A. Saint-Hilaire 1589 (holotype P, photo!).

Figs. 4C .

Distribution and habitat:— Endemic to South America ( Colombia, Venezuela, Guyana, Paraguay and Brazil). In Brazil this species occurs in the states of Acre, Minas Gerais, Goiás, Mato Grosso, Mato Grosso do Sul, Rio de Janeiro and São Paulo. It inhabits wet clay and dry soils in fields of Amazon Rain Forest and Cerrado. Flowering and fruiting occurs throughout the year.

Specimens examined:— BRAZIL. Goiás: Santa Izabel , 17 June 1979, F. Cardoso da Silva et al. 160 ( SP) ; Vale do Poronã , 05 February 1967, A. P. Duarte 10341 ( HB) . Mato Grosso: Barra do Garças , s.d., D. R. Hunt 5943 ( SP) ; Novo Santo Antônio , 19 August 2005, H. Jancoski et al. 242 ( SP) ; Porto Esperidião , November 1908, F. C. Hoehne 803 ( SP) . Mato Grosso do Sul: Aquidauana, 17 July 1969, G. Hatschbach & O. Guimarães 21995 ( MBM, SP) ; Campo Grande , 1969, E. F. Nienstedt 290 ( RB, SP) . Minas Gerais: Buritizeiro , 09 June 1990, G. Hatschbach et al. 54148 ( MBM) ; 03 April 1992, G. Hatschbach et al. 56490 ( MBM) ; São Romão , 22 August 1990, E. Tameirão Neto 521 ( BHCB) .

Melochia graminifolia resembles M. simplex in its general aspect, but is quite different in inflorescence organization, longer and narrower leaf blades with sparsely serrate margins and short, distant teeth.

Conservation status:— Endangered ( IUCN 2011). Registered known to exist at no more than five localities, and not found in conservation areas.

Figures

FIGURE 3. A. M. regnellii, branch with white flowers. B. Melochia villosa var. tomentosa, branch with lilac petals. C–D. M. pyramidata: C. branch with flowers and fruit, D. flowers having purple petals with yellow basal spots. E–G. M. gardneri: E–F. parts of the branches showing the axillary inflorescences, G. shrubby habit. H. M. pilosa, terminal inflorescence with yellow flowers. I. M. arenosa, branch with flowers having lilac petals with yellow basal spots. J. M. gardneri, branch with globose capsule with dehiscence partially loculicidal and septicidal. K. M. arenosa, part of branch with globose capsules. L. M. pyramidata, part of branch with pyramidal capsules.

FIGURE 4. Scanning Electron Microscopy of seeds in Melochia. A–I. Reticulate seeds: A. M. arenosa; B. M. simplex; C. M. graminifolia; D. M. regnellii; E. M. villosa var. villosa; F. Melochia villosa var. tomentosa; G–H. M. pilosa, H. showing the deciduous hull; I. M. gardneri J–L. Striate seeds: J. M. betonicifolia; K. M. morongii; L. M. pyramidata.

FIGURE 5. Scanning Electron Microscopy of trichomes in Melochia. A–B. M. pyramidata. biradiate trichomes on the outer calyx surface; C. M.simplex. peduncle, multiradiate trichomes; D. M. pyramidata. capitate-glandular trichomes on the outer calyx surface;E. M.regnellii. simple trichomes on the adaxial surface of leaf-blade; F. M. villosa var. villosa. stellate trichomes on the adaxial surface of leaf-blade.