Stachytarpheta, Vahl, 1804

Cardoso, Pedro Henrique, Neto, Luiz Menini, Cabral, Andressa & Trovó, Marcelo, 2021, Taxonomic updates in Brazilian Stachytarpheta (Verbenaceae) with atropurpureous to black corollas: Two new species and a new synonym, Phytotaxa 523 (2), pp. 167-178 : 176

Identification key for the Brazilian Stachytarpheta with atropurpureous to black corollas

1. Leaves glabrous..................................................................................................................................................................................2

1’. Leaves hairy........................................................................................................................................................................................5

2. Branches puberulous to pubescent; leaves 3-verticillate, blade obovate to rhomboid............................................... S. rhomboidalis

2’. Branches glabrous; leaves opposite, blade ovate, elliptic, oblong, oblong-lanceolate or subrotund .................................................3

3. Shrubs, densely branched; branches woody, resistant, smooth; calyx green throughout..................................................... S. glauca

3’. Subshrubs, unbranched to little branched; branches reed-like, easily flattened, striated; calyx green, atropurpureous at the apex..4

4. Leaves ovate, obovate to subrotund, base cuneate non-amplexicaul ............................................................................ S. integrifolia

4’. Basal leaves oblong, the apical leaves oblong-lanceolate, base cordate and amplexicaul.......................................... S. oblongifolia

5. Leaf blade sparsely strigose; calyx puberulous................................................................................................................. S. puberula

5’. Leaf blade and calyx villose, sericeous, sericeous-strigose, or lanate................................................................................................6

6. Leaf base truncate to slightly cordate.................................................................................................................................................7

6’. Leaf base cuneate ...............................................................................................................................................................................8

7. Leaves ovate to broadly ovate, blade with apex obtuse to round; bracts and calyx lanose........................................... S. glazioviana

7’. Leaves elliptic to broadly elliptic, blade with apex acute to obtuse, apiculate; bracts and calyx sericeous ....................... S. sericea

8. Leaf margins coarsely serrate at the apex; bracts ovate, apex acute; calyx green-grayish.............................................. S. salimenae

8’. Leaf margins crenate-serrate at the apex; bracts oval-triangular to narrowly triangular, apex acuminate to caudate; calyx yellowgreenish...............................................................................................................................................................................................9

9. Leaves ovate to rotund, petiolate, petiole 0.5–1 cm long, smaller leaves present in the same axil; bracts 0.6–0.8 cm long, abaxially puberulous with trichomes concentrated at the base ................................................................................................ S. flavovirescens

9’. Leaves elliptic, sessile, smaller leaves absent in the same axil; bracts 0.9–1.2 cm long, abaxially villose .......................... S. mollis