Distimake maragniensis (Choisy) Petrongari & Sim.

Petrongari, Fernanda Satori, Simões, Ana Rita & Simão-Bianchini, Rosângela, 2018, New combinations and lectotypifications in Distimake Raf. (Convolvulaceae), Phytotaxa 340 (3), pp. 297-300 : 298

Distimake maragniensis (Choisy) Petrongari & Sim. -Bianch. comb. nov.

≡ Ipomoea maragniensis Choisy (1845: 351) . Type:— BRAZIL. “ in sepibus ad fluv. Itapicuru prov. Maragniensis ”, [1819], C.F.P. von Martius s.n. (Holotype: M!).

= Batatas tomentosa (Choisy) Choisy (1845: 337) var. elongata Choisy (1845: 337) ≡ Ipomoea contorquens ( Choisy 1845: 385) var. simplicifolia Meisner (1869: 286) . nom. superf. ≡ Merremia digitata var. elongata (Choisy) D.F. Austin & Staples (1983: 484) . Lectotype (designated here):— BRAZIL. “ In campis Sorocuba [Sorocaba] prov. St-Paul ”, 1834, P.W. Lund s.n. (G00135071!).

= Ipomoea contorquens var. heterophylla Meisner (1869: 286) . Lectotype (designated here):— BRAZIL. “ In campis siccis Ypanema Prov. S. Pauli ”, March 1834, L. Riedel s.n. [2014] ( LE 01041453 !; Isolectotype: LE 01041454 !, LE 01041455 !, LE 01041456 !, NY00319175 !).

Notes: —This is a taxon with a long history of identification problems. Choisy (1845) described the taxa Ipomoea contorquens , Ipomoea maragniensis and the variety Batatas tomentosa var. elongata . In Flora Brasiliensis (1869), Meisner synonymized I. maragniensis and B. tomentosa var. elongata under I. contorquens var. simplicifolia , which is a superfluous name according to Art. 52 of ICN. When Hallier (1893) transferred several Convolvulaceae species to Merremia , he probably used Meisner’s concept of Ipomoea contorquens , which then encompassed all varieties, for the combination Merremia contorquens (Choisy) Hallier f. (1893: 552) , only citing the stellate indumentum as character. This wider concept was then accepted in subsequent herbarium identifications and taxonomic reviews (e.g. Hoehne 1922, O’Donell 1941).

Recently, Austin & Staples (1983), proposed the combination Merremia digitata var. elongata , and cited Ipomoea contorquens and I. maragniensis as synonyms of this variety.After careful study we believe the type variety of Ipomoea contorquens [≡ Distimake contorquens (Choisy) A.R. Simões & Staples (2017: 574) ], treated in Flora Brasiliensis (1869) as variety “ vulgaris” (an illegitimate name for the type variety), is a distinct taxon from M. digitata var. elongata , which only shares the dense stellate indumentum with the other taxa described by Choisy ( I. maragniensis and B. tomentosa var. elongata ) and Meisner ( I. contorquens var. heterophylla ). We consider that these names in fact represent a single entity, which we recognize at species level based on their shared characters of having an herbaceous twining habit, dense stellate indumentum and simple (rarely trifoliate) leaves. Ipomoea maragniensis is the only validly published name at this level so we are taking up that name and combining it as Distimake maragniensis .

To lectotypify Ipomoea contorquens var. heterophylla we analyzed images of the Riedel collections sent by LE herbarium, and we were able to identify two collections (L. Riedel “2014” and L. Riedel “2345”), each one with several duplicates, which match the protologue and were identified by Meisner. The specimens of the collection “ 2014 ” are identified as “ I. contorquens var. heteromorpha ”, later published as “ heterophylla ”, and the collection “ 2345 ” is identified as “ I. contorquens ”. The three distinct morphological types shown in the Flora Brasiliensis (1869) illustration “Tab. CIII Fig. II–IV” match the specimens, “Fig. II–III” being more similar to the collection “ 2014 ”, and “Fig. IV” to “ 2345 ”. We are choosing the specimen LE 01041453 of the collection “ 2014 ” as lectotype because it has more reproductive elements, including fruits, and a complete label with field information and Meisner’s handwriting. Regarding lectotypification of Batatas tomentosa var. elongata , of the two syntypes cited by Choisy, the specimen G00135071 has a more complete inflorescence and so is selected as a lectotype.