Tuesday, May 30, 2017

[Botany • 2017] Calliandra mayana • A New Narrowly Endemic Species (Leguminosae, Mimosoideae) from Campeche, Mexico

Calliandra mayana  H.M. Hern.


A new species of Calliandra (Leguminosae, Mimosoideae, tribe Ingeae) from a restricted locality of Campeche, Mexico is herein described and illustrated. The species appears to be closely related to C. molinae, a species from Honduras, El Salvador and Nicaragua, from which it may be distinguished by being allopatric, and by a more limited development of suberose bark in stems and branches, comparatively smaller leaflets, consistently glabrous leaflets and corollas, and by the scarcely villous pods. Calliandra mayana appears to be restricted to an extremely small seasonally flooded savannah surrounded by tropical deciduous forest and, based on IUCN criteria, it is provisionally considered Critically endangered.

Keywords: Calakmul, Calliandra belizensis, Fabaceae, Flora Mesoamerica, legumes, Eudicots

Figure 2. Calliandra mayana in its habitat.
A. Habit. B. Main stem. C. Branch. D. Inflorescence with three flowers beginning anthesis. E. Branchlets showing remains of inflorescences damaged by Lepidoptera and Coleoptera larvae (arrows). Voucher: H.M. Hernández et al. 4122 (MEXU). 

Calliandra mayana H.M. Hern., sp. nov. 

Calliandra mayana is closely related to C. molinae from which may be distinguished by being smaller shrubs up to 4 m (vs. 7 m), by the branchlets with bark slightly suberose (vs. thickly suberose), by the smaller petioles, rachis, rachillae and leaflets and less numerous pairs of pinnae and leaflets (vs. leaf parts larger and more numerous), and by the glabrous leaflets and corollas (vs. pubescent leaflets and villous corollas). 

Type:— MEXICO. Campeche, municipality Hopelchén, 9 km S of Pachuitz, 20 August 2016 (fl), H.M. Hernández et al. 4122 (holotype: MEXU 1446712!; isotypes: CICY!, ENCB!, K!, MEXU!, MO!, NY!, TEX!, US!, XAL!). 

Etymology:— This species in named to honour the Maya, an indigenous people that has continuously inhabited parts of south-eastern Mexico and Central America during several millennia. The Maya civilization flourished in the Yucatan Peninsula, Chiapas, Guatemala and Belize, and the western portions of Honduras and El Salvador, from 2000 BC to 950 AD.

Distribution and habitat:— Calliandra mayana is currently known only from an extremely small seasonally flooded savannah area surrounded by forest in Calakmul, eastern Campeche, Mexico, close to the Quintana Roo border, at 80 meters elevation (Figure 4). The Calakmul area is the largest tract of well-preserved tropical deciduous and sub-deciduous forest in Mesoamerica.

Héctor M. M. Hernández and Carlos Gómez-Hinostrosa.  2017. Calliandra mayana (Leguminosae, Mimosoideae), A New Narrowly Endemic Species from Campeche, Mexico.  Phytotaxa.  307(4); 278–284. DOI: 10.11646/phytotaxa.307.4.5