Macropsychanthus Harms in K. Schumann & Lauterbach, Fl. Schutzgeb. Suedsee 366. 1900.

Queiroz, Luciano Paganucci de & Snak, Cristiane, 2020, Revisiting the taxonomy of Dioclea and related genera (Leguminosae, Papilionoideae), with new generic circumscriptions, PhytoKeys 164, pp. 67-114 : 67

4. Macropsychanthus Harms in K. Schumann & Lauterbach, Fl. Schutzgeb. Suedsee 366. 1900.

Type.

Macropsychanthus lauterbachii Harms.

Description.

Stout, high-climbing lianas with twining stems, less frequently shrubs or woody vines in open habitats. Stipules medifixed and prolonged below their insertion (peltate) or basifixed and not prolonged below their insertion. Leaves pinnately trifoliolate, stipellate or estipellate. Inflorescence a stout, woody, erect pseudoraceme, nodes multiflorous, woody, stalked and secundiflorous; bracteoles fleshy. Flowers massive; calyx with the tube fleshy coriaceous, upper edge convex or humped, 4-lobed, with the upper lobe either entire and triangulate to obtuse or emarginate and then with the resulting tips rounded or 5-lobed with the two upper lobes rounded and the other three lobes triangulate, the lower lobe much longer than the remaining lobes or deeply bilabiate with two oblong lips; petals firm, the standard petal reflexed, somewhat fleshy, bicallose, provided with two basal and folded auricles, wing petals ca. twice as long as the keel, obliquely oblong, obliquely ovate, obovate, elliptic to almost quadrate, basal spur at the upper margin present or lacking, keel upcurved, the keel petals triangular or semi-lunar, extending distally into a slender, obtuse or truncate beak; androecium pseudomonadelphous, the 10 stamens joined in a tube, but the filament of the vexillary stamen free at the base, anthers mostly dimorphic, 5 fertile alternating with 5 sterile or 6 fertile and 4 sterile or anthers uniform and all 10 fertile; intrastaminal nectary disc 10-dentate or 10-lobed; ovary sessile, style usually swollen distally. Fruit indehiscent, passively dehiscent or elastically dehiscent with twisting woody valves, turgid, slightly compressed or flat compressed, valves coriaceous, fleshy or woody, upper margin smooth or provided with ribs or wings. Seeds 3-5 to 9, massive, either orbiculate and slightly compressed with a hard testa or soft overgrown and without a definite shape, with flat contact planes or elliptic and flat compressed; hilum linear, encircling 1/2 to 4/5 of the seed’s circumference or short and oblong. Fig. 3 .

Discussion. Macropsychanthus Harms is the earliest validly-published genus name for this group. Two older names, Lepidamphora Zolling. and Taurophtalmum Duchaiss., were not validly published. Lepidamphora volubilis Zolling. was published as a synonym of Dioclea javanica Benth. with the citation of two specimens (" Herb. n. 763 et 867 Z. "; Miquel 1855: 217). Lepidamphora volubilis was probably just a name on herbarium sheets and is invalid because it was published as a synonym (ICN Article 36.1; Turland et al. 2018) and because it was published as a species, but the genus to which it was assigned was not validly published at the same time or was not validly published previously (Art. 35.1; Turland et al. 2018).

The Panamanian Taurophtalmum pulchrum Duchaiss. was another invalidly-published name that could be related with Macropsychanthus as defined here. It was originally published as a synonym of Canavalia miniata (Kunth) DC. by Griesebach (1866: 76). However, Urban (1899: 473) placed T. pulchrum as a synonym of Dioclea reflexa Hook. f. (= Macropsychanthus comosus ), based on the calyx description provided earlier by Grisebach (1866). The only specimen of Canavalia or Dioclea collected by Duchassaing that we were able to track is the type of Dioclea panamensis Duchaiss. ex Walp. (Duchassaing s.n. [GOET 004985]), which is a synonym of Dioclea guianensis Benth. and thus does not belong to Macropsychanthus as circumscribed here. There is a plate from Duchaissang housed at GOET (and annotated as Canavalia miniata by Griesebach) that probably represents the only remnant of the original material of Taurophtalmum pulchrum . It is a watercolour painting of a fruit and a seed with a pencil sketch of a flower and a detailed description by Duchaissang (Fig. 4 ). The fruit represented probably belongs to Macropsychanthus megacarpus and not to M. comosus as supposed by Urban (1899). The name Taurophtalmum literally means "bulls eye" and was probably derived from the Spanish name "ojo de buey" for several species of Macropsychanthus (also common in Portuguese as “olho-de-boi”), but not for species of Dioclea . In the absence of a specimen and taking the painting in GOET as evidence, we are considering Taurophtalmum as related to Macropsychanthus , although it is an invalid name.

Two major clades were recovered corresponding to the circumscription of Macropsychanthus proposed here. One (clade D) brings together species formerly ascribed to the genera Luzonia and Macropsychanthus , as well as to Dioclea subg. Pachylobium and Dioclea huberi (subg. Platylobium sect. Macrocarpon ; Maxwell 2011). Clade C comprises all of the other species formerly ascribed to Dioclea subg. Platylobium . Clade D includes species with mostly medifixed stipules, fruits indehiscent or passively dehiscent and turgid seeds with a long, linear hilum; clade C includes species with basifixed stipules, fruits flat-compressed and elastically dehiscent and seeds with a short and oblong hilum. Our finding that the puzzling Dioclea huberi (formerly classified in subg. Platylobium sect. Macrocarpon ) is part of clade D blurs the distinction between those major clades, because it shares basifixed stipules and flat-compressed fruits and seeds with D. subg. Platylobium , but seeds with a long linear hilum with D. subg. Pachylobium . Likewise, Dioclea macrocarpa , recovered in clade C, shows the basifixed stipules and the short and oblong hilum of D. subg. Platylobium together with the turgid fruits and seeds of D. subg. Pachylobium . Thus, clades B and C are diagnosed by only a few morphological traits (see below) and we chose to recognise them as subgenera of a largely polymorphic genus instead of treating them as two separate genera.

Macropsychanthus is a pantropical genus with 46 species. It is most diverse in the New World (36 species), with eleven species from the Philippines and Indonesia to New Guinea and two Pantropical sea-drifted species extending to continental Africa and Madagascar.

Figures

Figure 3. Representatives of the clade B. Macropsychanthus subg. Macropsychanthus (A-F). Macropsychanthus grandiflorus (Mart. ex Benth.) L. P. Queiroz & Snak A flowering vine (from Queiroz 15227). Macropsychanthus marginatus (Benth.) L. P. Queiroz & Snak B mature fruit showing dehiscence through the lower suture only C one of the valves removed to show the seeds with a long linear hilum (arrow; from Queiroz 15225). Macropsychanthus edule (Kuhlm.) L. P. Queiroz & Snak D the indehiscent and fleshy fruit decahing to release the seeds (from Popovkin 1546). Macropsychanthus lauterbachii Harms var. lauterbachii E giant flowers with bluish petals (unvouchered). Macropsychanthus megacarpus (Rolfe) L. P. Queiroz & Snak F flower (from Queiroz 10135). Macropsychanthus subg. Platylobium (G-J). Macropsychanthus scabrus (Rich.) L. P. Queiroz & Snak G flowers (from Cardoso 2907). Macropsychanthus bicolor (Benth.) L. P. Queiroz & Snak H part of the pseudoracemous inflorescence I mature (left) and dehisced (right) fruits J seed, showing the short hilum (arrow; from Queiroz 15874). Photos A-C, F, H-J: L. P. Queiroz; D: A. Popovkin; E: A. D. Poulsen; G: D. Cardoso.

Figure 4. Lectotype of Taurophtalmum pulchrum Duchaiss. This watercolour painting housed at GOET is the only remnant of the original material of this species cited in Griesebach (1866).