Cuphea sect. Trispermum Koehne (1881: 163)

Facco, Marlon Garlet & Cavalcanti, Taciana Barbosa, 2023, Taxonomic Revision of Cuphea sect. Trispermum s. l. (Lythraceae), Phytotaxa 588 (1), pp. 1921-1935 : 1921-1935

Cuphea sect. Trispermum Koehne (1881: 163) ,

here as Cuphea sect. Trispermum Koehne sensu lato (including C. carajasensis , C. congesta , C. micrantha , C. odonellii , C. pulchra and C. tenuissima ) emend. M.G.Facco & T.B.Cavalcanti. Cuphea sect. Balsamona Koehne subsect. Trispermum Koehne (1877: 219, 228, 283). Lectotype (designated by Lourteig 1987 ):— Cuphea antisyphilitica Kunth.

Cuphea sect. Brachyandra Koehne subsect. Micranthium Koehne (1903: 90, 120) .

Lectotype (here designated):— Cuphea micrantha Kunth.

Subshrubs to shrubs, 10–200 cm tall; stems erect to decumbent, indumentum strigose, pubescent, glandular or hirsute, rarely bifid-malpighiaceous trichomes present; sometimes brachyblasts present. Leaves opposite to 3(–4–5)-verticillate, blades elliptic, ovate, oblong to linear, margin plane, subrevolute to strongly revolute to the midvein, hyphodromous to brochidodromous. Racemes bracteose, frondose-bracteose to frondose, simple to compound, elongated to contracted at apex of branches; bract pairs subequal, rarely unequal, with one of the bracts of the pair much smaller in size. Flowers alternate, rarely opposite, sometimes clustered at the apex of the branches, pedicels 1–9 mm long, interpetiolar, rarely axillary; floral tubes 4–24 mm long, spur obtuse, saccate to galeate, rarely acute, deflexed, rarely horizontal, outer surface vinaceous or atropurpureous in the dorsal region and green ventrally, sometimes red-orange or yellow-green, rarely pale green; petals 6, rarely 0, lilac, pink, purple, yellow, rarely red-orange, carmine or white, subequal, rarely the two dorsal petals smaller than the four ventral ones; stamens 11, filaments free in the upper third of the floral tube, exserted to subexserted, or in the middle third of the floral tube, with fully included stamens, the 2 dorsalmost shortest and most deeply inserted in tube; infrastaminal vesicles 0; pollen tricolporate, psilate, exine thickened between the pores; pistil 2–23 mm long; ovary glabrous to slightly pilose, rarely densely villous dorsally; ovules 3, rarely 2, 4–8; nectary deflexed, rarely horizontal, convex in the dorsal region, concave ventrally. Seeds 2–3, rarely 1 or 4, 1.5–3.2 × 1.2–2.9 mm, elliptic, obovate to suborbicular, margin obtuse, rarely slightly thickened.

Key to species of Cuphea sect. Trispermum s.l.

1. Leaves hyphodromous, linear or narrow-ovate ..................................................................................................................................2

- Leaves brochidodromous, ovate, narrow-ovate, oblong to elliptic ..................................................................................................11

2. Brachyblasts present (lateral branches with strongly reduced internodes, with verticillate to rarely opposite leaves) .....................3

- Brachyblasts absent ............................................................................................................................................................................5

3. Leaf margin plane; flowers yellow................................................................................................................................... C. paralarix

- Leaf margin revolute; flowers lilac to purple, rarely white................................................................................................................4

4. Leaves 3-verticillate; plants decumbent. Northeast Brazil.............................................................................................. C. laricoides

- Leaves opposite; plants erect. Central-Western Brazil (Mato Grosso) .................................................................... C. araguaiaensis

5. Racemes frondose, indistinct from foliage, or racemes contracted at apex of branches....................................................................6

- Racemes bracteose, distinct from foliage, elongated, never contracted at apex of branches.............................................................9

6. Branches, leaves and floral tubes with bifid-malpighiaceous trichomes, with two conspicuous arms............................. C. odonellii

- Branches, leaves and floral tubes never with bifid-malpighiaceous trichomes..................................................................................7

7. Leaves 3–5-verticillate; branches pubescent, mixed with glandular trichomes; floral tube atropurpureous ................... C. ericoides

- Leaves opposite; branches strigose, with one-armed trichomes, mixed with glandular trichomes; floral tube never atropurpureous ............................................................................................................................................................................................................8

8. Petals white, the dorsal smaller than the ventral; racemes short, 1.5–4 cm long, contracted at apex of branches .............................. ............................................................................................................................................................................ C. cunninghamiifolia

- Petals pink, subequal; racemes elongate, 9–15 cm long, not contracted at apex of branches..................................... C. rionegrensis

9. Leaf margin plane, rarely subrevolute; stem pubescent to glabrescent; ovary densely villous in dorsal region ........ C. carajasensis

- Leaf margin strongly revolute to the midvein; stem strigose, one-armed trichomes, and hirsute; ovary glabrous, rare pilose.......10

10. Leaves uniformly opposite; floral tubes small and slender, (4–) 5–6.7 mm long; stamens fully included, filaments free in middle third of floral tube........................................................................................................................................................... C. tenuissima

- Leaves 3–4(–5)-verticillate at midstem, opposite distally; floral tubes larger and thicker, (6–) 7–8 mm long; stamens exserted and subexserted, filaments free in upper third of floral tube ............................................................................................ C. praetermissa

11. Floral tubes 15–24 mm long, red-orange or yellow-green...............................................................................................................12

- Floral tubes 4–13 mm long, purple or vinaceous in dorsal region, green ventrally, or yellow-green to pale green ........................13

12. Floral tubes yellow-green; petals 6, pale yellow; racemes frondose, elongated. Venezuela............................................. C. congesta

- Floral tubes red-orange; petals 0 or 6, red-orange; racemes bracteose, contracted at apex of branches. Brazil................. C. pulchra

13. Floral tubes completely yellow-green, rare pale green; petals yellow .............................................................................................14

- Floral tubes purple or vinaceous in dorsal region, green ventrally; petals pink, purple to red ........................................................16

14. Floral tubes 10–13 mm long; branches with bifid-malpighiaceous or one-armed trichomes. Venezuela..................... C. anisoclada

- Floral tubes 5–9 mm long; branches with other types of trichomes. Brazil.....................................................................................15

15. Leaves strigose, one-armed trichomes, mixed with sparse glandular trichomes; floral tubes 5–7.2 mm long, pubescent and glandular. Rocky fields of the Espinhaço Range (“campo rupestre”) .......................................................................................... C. auriflora

- Leaves usually glabrous, sometimes glandular-ciliate margin; floral tubes 7–9 mm long, glabrous or just glandular. Sandy coastal plains (“restinga”).................................................................................................................................................................... C. flava

16. Floral tubes 4–6 mm long; stamens fully included, filaments free in middle third of floral tube................................... C. micrantha

- Floral tubes 5–9 mm long; stamens exserted to subexserted, filaments free in upper third of floral tube, when free in middle third, one bract of the pair much smaller in size ( C. inaequalifolia ) .........................................................................................................17

17. Racemes with unequal bract pairs, with one of the bracts of the pair much smaller in size ..................................... C. inaequalifolia

- Racemes with subequal bract pairs...................................................................................................................................................18

18. Racemes bracteose, elongated, distinct from the foliage .................................................................................................................19

- Racemes frondose to frondose-bracteose, indistinct from foliage ...................................................................................................21

19. Leaves imbricate, coriaceous, ovate to broad-ovate, base cordate................................................................................... C. bahiensis

- Leaves not imbricate, membranaceous, narrow-ovate, base acute, obtuse to truncate ....................................................................20

20. Ovary densely villous in dorsal region; branches pubescent to glabrescent. Brazil (Pará)......................................... C. carajasensis

- Ovary glabrous to pilose; branches strigose, one-armed trichomes. Venezuela and Colombia.......................................... C. gracilis

21. Branches, leaves and floral tubes with bifid-malpighiaceous trichomes, with two conspicuous arms............................. C. odonellii

- Branches, leaves and floral tubes with glandular and one-armed appressed trichomes........................................... C. antisyphilitica