Phaseolus pachyrrhizoides Harms (1921: 504)

Debouck, D. G., 2021, Phaseolus Beans (Leguminosae: Phaseoleae): A Checklist And Notes On Their Taxonomy And Ecology, Journal of the Botanical Research Institute of Texas 15 (1), pp. 73-111 : 81-82

Phaseolus pachyrrhizoides Harms (1921: 504) [clade B; sect. Paniculati Freytag]. TYPE: A Weberbauer 1769 ( HOLOTYPE: B n.v.) .

The type was probably lost in the fire of B in 1943; it is survived as a black-and-white photograph with number 2440 (seen by the author at G and US). It was probably a unicate because the author has not seen any other specimen with that field collection number during this study. August Weberbauer (1945) mentioned this taxon only once (and without any number) from the surroundings of Huacapistana, Junín, while Francis McBride (1943) mentioned a few collections from Junín and Huánuco. Zarucchi and co-workers (1993) reported it to be present also in Ayacucho and Huancavelica. Material that matches well the description given by Hermann Harms, namely in raceme size and size and shape of primary bracts and bracteoles, is DG Debouck 2149 (BR, COL-236000, MICH, UC-1571119, US-3168424, USM n.v.) found not far from Huacapistana in JunÍn, Peru. The following specimens give indication about the range of this taxon (note it is within the range of P. augusti reported here and by Zarucchi et al. 1993).

Specimens : PERU. Amazonas: R Ferreyra 15552 (USM-26770). Cajamarca: DG Debouck 2011 ( MO-2828586 ). Huánuco: PG Smith s.n. (USM-26765). Junín: TB Croat 57694 (USM-56590). Apurimac: DG Debouck 2294 ( UC-1716200 ).

While P.augusti and P. pachyrrhizoides share the same pollen type ( Maréchal et al. 1978a), differences between populations of both taxa revealed by biochemical ( Maquet et al. 1999) and molecular studies ( Caicedo et al. 1999; Delgado-Salinas et al. 1999; Fofana et al. 1999) seem to be of the same magnitude as those between gene pools within wild Lima or common bean. Having studied in the field 36 populations of P.augusti and 24 of P. pachyrrhizoides , respectively, and in herbaria 112 and 40 specimens, respectively, the following synonymy can be proposed:

Phaseolus pachyrrhizoides Harms , based on A Weberbauer 1769 (B, as holotype,lost;photographed by Chicago Natural History Museum , formerly Field Museum of Natural History ,through the Rockefeller Foundation Fund for Photographing Type Specimens , Types of the Berlin Herbarium, b/w photograph nr. 2440, in G and US),and originally published in:Notizbl. Bot. Gart. Mus. Berlin-Dahlem 7:504.1921.

= Phaseolus augusti Harms , based on A Weberbauer 6439 ( GH-64117 ) as isotype (see above), and originally published in: Notizbl. Bot. Gart. Mus. Berlin-Dahlem 7:503.1921.