Psyllocarpus sect. Psyllocarpus

Sobrado, Sandra V., do Carmo, João A. M., Simões, André O. & Salas, Roberto M., 2022, Two new species of Psyllocarpus (Spermacoceae, Rubiaceae) from the state of Minas Gerais, southeastern Brazil, European Journal of Taxonomy 806, pp. 161-176 : 173

Key to the species of Psyllocarpus sect. Psyllocarpus (adapted from Carmo et al. 2018)

1. Inflorescences in pauciflorous cymes; hypanthium hirsute to sparsely hirsute; capsules hirsute, valves deciduous keeping the seed inside after dehiscence ........................................................................... ............................................................ Psyllocarpus bahiensis J.A.M.Carmo, Sobrado & R.M.Salas

– Inflorescences in 1-flowered cymes or glomerules; hypanthium glabrous or the upper ½ puberolous; capsules glabrous or the upper ⅓ sparsely puberulous, valves persistent from which the seeds are shed after dehiscence ........................................................................................................................ 2

2. Flowering branches indeterminate, axillary inflorescences in 1-flowered cymes ............................ 3

– Flowering branches determinate, terminal inflorescences in glomerules ......................................... 5

3. Leaf axils generally without brachyblasts, rarely with 1(2) pairs of smaller leaves; stigma capitate. ..................................................................................................... Psyllocarpus schwackei K.Schum.

– Leaf axils always with 2–9 pairs of brachyblasts or short branchlets; stigma bilobate .................... 4

4. Sympodial subshrub; hypanthium glabrous; calyx tube present (0.1–0.5 mm long); corolla lobes rounded in preanthetic buds; capsules glabrous; seeds elliptic to broadly elliptic in outline ............. ............................................................................................... Psyllocarpus laricoides Mart. & Zucc.

– Monopodial subshrub; hypanthium with the upper ⅓ puberulous; calyx tube absent; corolla lobes capitate angulate in preanthetic buds; capsules with the upper ⅓ sparsely puberulous; seeds narrowly oblong in outline ........................................................................ Psyllocarpus goiasensis J.H.Kirkbr.

5. Flowering branches dichasial or monochasially branched, or unbranched; calyx lobes 4.3–4.8 mm long; corolla lobes capitate angulate in preanthetic bud, mature corolla 6.5–7.5 mm long ............... ............................................................ Psyllocarpus scatignae J.A.M.Carmo, Sobrado & R.M.Salas

– Flowering branches unbranched; calyx lobes 1.2–3.6 mm long; corolla lobes rounded or clavate in preanthetic bud, mature corolla 1–3.6 mm long ............................................................................... 6

6. Corolla completely white, sometimes the lower half of the tube purple; distributed in Minas Gerais, Bahia, and Goiás, and the Distrito Federal ....................................................................................... 7

– Corolla completely purple, sometimes with the lower half of the tube white, or the lower half the tube purple, the upper half and lobes light blue; endemic to Minas Gerais ...................................... 8

7. Flowering branches erect; calyx lobes 1.2–2 mm long; corolla tube 1.1–1.5 mm long; seeds broadly elliptic in outline .............................................................. Psyllocarpus asparagoides Mart. & Zucc.

– Flowering branches pendulous; calyx lobes 2.2–3.6 mm long; corolla tube 2.2–2.6 mm long; seeds obovate in outline ............................................................... Psyllocarpus phyllocephalus K.Schum.

8. Calyx tube absent to vestigial, 3–5 fimbriae between calyx lobes; corolla infundibuliform, tube 1.78–2.08 mm long, lower half purple, upper half and lobes light blue, internal surface with a dense ring of moniliform trichomes from the anthers apex to the lobes base, sparsely pubescent between the anthers, and glabrous on the base; corolla lobes rounded in preanthetic bud, apex rounded, and plane to slightly reflexed in mature flowers; stamens inserted at the middle of the corolla tube........ ........................................ Psyllocarpus itakangapyra Sobrado, J.A.M.Carmo & R.M.Salas sp. nov.

– Calyx tube present (0.15–0.45 mm long), 6–10 fimbriae between calyx lobes; corolla urceolate, tube 1.22–1.6 mm long, completely purple or the lower half of the tube white, internal surface glabrous from the base up to the base of the filaments, and sparsely monoliform trichomes between the anthers, corolla lobes deeply deltoid in preanthetic buds, apex mucronate, and the upper third patent reflexed from posanthetic to mature flowers, the rest aligned with the adjacent lobes forming a false tube; stamens inserted near the sinuses of the corolla lobes ........................................................................ .................................................. Psyllocarpus vianae Sobrado, J.A.M.Carmo & R.M.Salas sp. nov.