Notes on Apeiba (Malvaceae)

Curation notes on Apeiba (formerly Tiliaceae, now Malvaceae: Grewioideae)
           by a taxonomic generalist trying to make sense of a stack of specimens.

     Apeiba is a genus of ten species of fast-growing trees up to 30 m tall, from lowland neotropical forests, often in riparian habitats. Apeiba tibourbou is the most widespread species, occurring from Mexico south to Bolivia, the Guianas, and central Brazil. However, genus diversity is concentrated in northern South America. The wood of Apeiba is soft and lightweight and used for rafts, the bark fibrous and used for making rope (Dorr & Meijer 2005). The fruits are conspicuous woody-capsules, globose (A. trombetensis) to flattened-globose, and covered with spines or bristles, giving the plant the local name of "monkey's comb" ("pente de macaco" in Portuguese, "peine de mono" in Spanish, according to several specimen labels).
    The genus is divided into two sections. Section Tibourbou (A. albiflora, A. schomburgkii, A. tibourbou) and section Petoumo (A. glabra, A. intermedia, A. macropetala, A. membranacea, A. petoumo, A. trombetensis, A. uittienii). The differences are summarized by Dorr (2012) as follows:
    Section Tibourbou: "serrate leaf blades, long simple hairs on twigs and new leaves, and capsules with hirsute bristles and woody teeth surrounding the apical ostiole-like hole."
    Section Petoumo: leaf blades entire to subentire, twigs and young leaves without long simple hairs (frequently stellate hairs present), and capsules "with nearly glabrous bristles or spines, opening apically with a nearly circular ostiole-like hole that lacks teeth."
            I don't have the treatment in the Flora of the Guianas (1995) available here, but Dorr & Meijer (2005) include a key to all recognized species, except for A. intermedia (known from only one tree in Surinam) and A. trombetensis, published in 2012. A revision of the genus was conducted by Howard Setser (1977) and is found in an unpublished doctoral dissertation (which I have not seen).
 
"Apeiba aspera"
    Apeiba aspera is a name that has frequently been misapplied to the Central American and western Amazonian species A. membranacea, and in other contexts to the mostly Guianan species A. petoumo. Jansen-Jacobs & Meijer (1995) noted that the type of A. aspera, collected in French Guiana, is a mixed collection of A. glabra and A. petoumo, and lectotypified the name so that A. aspera is to be treated as a synonym of A. glabra, a species common in the Guianas and northeastern Amazonian Brazil (Amapá, Maranhão, and Pará), but not known from western Amazonian Peru and Ecuador. This treatment was accepted by Dorr & Meijer (2005).
    The Catalogue of the Flora of Peru (1993) may have created confusion by citing A. aspera as a synonym of A. membranacea, rather than as a misapplied name. If this were true, the correct name for the species would be A. aspera, the older name.
    Additional confusion may have been created by the citation in TROPICOS of A. aspera as an accepted name, with A. echinata as synonym, according to  "Steyermark, J.A. 1995. Flora of the Venezuelan Guayana Project." Not all users may be aware that this particular literature reference in TROPICOS refers to an informal preliminary list which often has no resemblance to the taxonomy later published in the actual Flora of Venezuelan Guayana. Thus TROPICOS users who do not have the published Fl. Venez. Guayana in hand may be misled.
    The Catalogue of the Flora of Ecuador (1999) contains the correct information that the Ecuadorean species is A. membranacea, previously misidentified as A. aspera. However, Neill & Ulloa (2011) have resurrected A. aspera for Ecuador, with A. membranacea listed as a taxonomic synonym. The change is marked by the authors with an asterisk(*), indicating that the new record is based on a new taxonomic circumscription, but no literature reference is cited, and I can't locate any. It may be a simple misunderstanding. In the meantime, much of the most recently collected material from Ecuador and Peru in TROPICOS is again being identified as A. aspera. Wrongly, it seems, unless someone has unpublished knowledge to the contrary.

Apeiba albiflora & A. schomburgkii
           In herbarium found partly filed under A. tibourbou.
Apeiba macropetala
           Our material mostly filed as A. echinata var. macropetala, following Setser (1977).
Apeiba petoumo
           Much of our material was filed under A. echinata, following Setser (1977).

References:
Brako, L. & J. L. Zarucchi. (eds.) 1993. Catalogue of the Flowering Plants and Gymnosperms of Peru. Monogr. Syst. Bot. Missouri Bot. Gard. 45: i–xl, 1–1286.

Dorr, L.J. 2012. Apeiba trombetensis (Malvaceae: Grewioideae), a new species from northern Brazil. Brittonia 64: 374-380.

Dorr, L.J. & W. Meijer. 2005. Apeiba. In: Berry et al., eds. Flora of the Venezuelan Guayana 9: 345-348.

Jansen-Jacobs, M.J. & W. Meijer. 1995. Apeiba. In: A.R.A.Görts-van Rijn, ed. Flora fo the Guianas, ser. A, 17: 7-18. [not seen by me]

Jansen-Jacobs, M.J. & L.Y.Th.Westra. 1995. A new species of Apeiba (Tiliaceae) from the Venezuelan-Brazilian border. Brittonia 47: 335-339. [Apeiba uittienii]

Jørgensen, P.M. & S. León-Yánez (eds.). 1999. Catalogue of the vascular plants of Ecuador. Monogr. Syst. Bot. Missouri Bot. Gard. 75: i–viii, 1–1182.

Neill, D. A. & C. Ulloa Ulloa. 2011. Adiciones Fl. Ecuador: Segundo Supl., 2005-2010 1–202. Fundación Jatun Sacha, Quito.

Setser, H.A. 1977. A revision of Neotropical Tiliaceae: Apeiba, Luehea, and Lueheopsis. Ph.D. Dissertation, University of Kentucky, Lexington, Kentucky.