Drosera species, 1753

Gonella, Paulo Minatel, Sano, Paulo Takeo, Rivadavia, Fernando & Fleischmann, Andreas, 2022, A synopsis of the genus Drosera (Droseraceae) in Brazil, Phytotaxa 553 (1), pp. 1-76 : 17-19

Key to the Drosera species in Brazil (modified from Gonella 2012, 2017, 2020)

Note: for the purposes of this key, when referring to leaf indumentum (glabrous, glandular- and/or eglandular pilose), the carnivorous tentacles and sessile glands are not considered; the petiole is the leaf portion lacking glandular emergences (tentacles). Numbers before the species’ names refer to their position in the Taxonomic Treatment below.

1. Leaves with glandular trichomes only; leaf vernation entire-involute; gynoecium 5-merous, styles 5, entire....... 26. D. sessilifolia

1’. Leaves glabrous, or eglandular-pilose only, or both glandular- and eglandular-pilose; leaf vernation of other type; gynoecium 3- merous, styles 3, bifurcated at the base (six stigmatic tips in total) .................................................................................................. 2

2. Stipules absent or reduced to two small setae on the margins of the leaf base .......................................................... 4. D. brevifolia

2’. Stipules well-developed, conspicuous, rectangular or triangular in outline, intrapetiolar ................................................................ 3

3. Stipules large, 6–22(–30) mm long, triangular in outline, usually golden-brown in living plants.................................................... 4

3’. Stipules smaller than 6 mm (very rarely exceeding 6 mm), rectangular in outline, or deeply divided from the base, usually white or red in living plants......................................................................................................................................................................... 9

4. Leaves sessile, exclusively eglandular-pilose, with circinate-involute vernation.................................................... 20. D. magnifica

4’. Leaves with petioles short to long, both glandular- and eglandular-pilose, with circinate vernation ............................................... 5

5. Leaves and inflorescences with short, stalked glandular trichomes (0.1–0.5 mm long).............................................. 27. D. spiralis

5’. Leaves and inflorescences with sub-sessile globose glandular trichomes (ca. 0.1 mm in diam.)..................................................... 6

6. Leaf lamina linear................................................................................................................................................. 12. D. graminifolia

6’. Leaf lamina lanceolate....................................................................................................................................................................... 7

7. Petiole and lamina with similar width.................................................................................................................... 22. D. quartzicola

7’. Petiole 2 to 3 times narrower than the lamina ................................................................................................................................... 8

8. Plants acaulescent (older specimens with short columns up to 3.5 cm long); active leaves only 1–3 (rarely 4 or 5) in number ........ ........................................................................................................................................................................... 5. D. camporupestris

8’. Plants with conspicuous stem, 1–46 cm long; active leaves 3–13 ........................................................................... 9. D. chrysolepis

9. Leaves, scapes and sepals with translucent-yellow sub-sessile globose glandular trichomes (ca. 0.1 mm in diam.).......................... ................................................................................................................................................................................. 25. D. schwackei

9’. Leaves exclusively eglandular-pilose or glabrous, glandular trichomes on scape and sepals, if present, conspicuously stalked and not as above ..................................................................................................................................................................................... 10

10. Leaves spatulate with petiole narrower and distinct from the lamina; lamina narrowly to broadly obovate or suborbicular ........ 11

10’. Leaves of other shapes, if spatulate then with petiole indistinct and gradually broadening into the lamina; lamina cuneate, ellipsoid, lanceolate, oblanceolate, oblong or obovate.................................................................................................................................... 22

11. Leaves entirely glabrous; petioles 3 or more times longer than the lamina; seeds with papillose testa, papillae more or less randomly distributed.................................................................................................................................................... 17. D. intermedia

11’. Leaves with eglandular trichomes (at least on abaxial surface and/or margins); petioles equal to the lamina in length or up to 2 times longer; seeds with reticulate, foveate or papillose testa, if papillose then papillae arranged in rows ................................... 12

12. Flowers sub-sessile (peduncle + pedicel shorter than the leaves) and solitary; pedicel erect in flower, bending downwards (reflexed) in fruit........................................................................................................................................................... 1. D. amazonica

12’. Flowers on a long conspicuous scape (longer than the leaves), inflorescence usually with more than one flower (rarely scapes uniflorous); pedicel erect in flower and in fruit............................................................................................................................... 13

13. Scape slightly to markedly curved (ascending) at its base.............................................................................................................. 14

13’. Scape erect at the base..................................................................................................................................................................... 18

14. Scapes densely eglandular-pilose (villous) in the basal half ........................................................................................................... 15

14’. Scapes glabrous at the base, or only sparsely eglandular-pilose (glabrescent) ............................................................................... 16

15. Leaf lamina obovate to suborbicular; scape green to red colored in live specimens; eglandular trichomes of the scape red ............. ...................................................................................................................................................................................... 15. D. hirtella

15’. Leaf lamina narrowly obovate to spatulate; scape yellow-green in live specimens; eglandular trichomes of the scape white........... ................................................................................................................................................................................... 19. D. lutescens

16. Plants often forming a conspicuous, erect column of marcescent leaves; abaxial leaf densely eglandular-pilose; seeds ellipsoid to rectangular; only present in uplands and highlands of Amazonas and Roraima ....................................................... 24. D. roraimae

16. Plants acaulescent (only forming long etiolated stems if growing in waterlogged habitats); abaxial leaf surface only sparsely eglandular-pilose (abaxial lamina surface often glabrous); seeds rectangular or fusiform; plants widespread (if present in Amazonas and Roraima then only at lower elevations) .................................................................................................................................... 17

17. Leaves entirely green or with reddish petiole and greener lamina (even if growing in sunny habitats); scape base erect to slightly curved; seeds rectangular (south of the Amazon only) .................................................................................................. 32. D. viridis

17’. Leaves red (green only in shaded habitats or if growing waterlogged); scape base arcuate (markedly curved); seeds fusiform (north and south of the Amazon)......................................................................................................................................... 10. D. communis

18’. Scape and sepals exclusively eglandular-pilose or both glandular- and eglandular-pilose; sepals lanceolate....... 7. D. cayennensis

18. Scape and sepals completely glabrous or exclusively glandular-pilose; sepals of other shapes..................................................... 19

19. Inflorescence rachis, pedicels, and sepals glandular-pilose; seeds rectangular.............................................................. 32. D. viridis

19’. Inflorescence rachis, pedicels, and sepals glabrous or, if glandular trichomes present, then restricted to the sepals; seeds ovoid ..... ......................................................................................................................................................................................................... 20

20. Sepals united only at the very base, reflexed in fruit ...................................................................................................... 3. D. biflora

20’. Sepals united up to half length, erect in fruit................................................................................................................................... 21

21. Pedicels equal to or longer than the sepals; sepals with acute to cuspidate apex; seeds with foveolate testa....... 11. D. esmeraldae

21’. Pedicels equal to or shorter than half sepal length; sepals with rounded to obtuse apex; seeds with papillose testa .......................... .................................................................................................................................................................................... 6. D. capillaris

22. Lamina oblong, lanceolate, or ellipsoid in outline (apex narrower or of similar width than the base)........................................... 23

22’. Lamina obovate, oblanceolate, spatulate, or cuneate in outline (apex distinctly broader than the base)........................................ 31

23. Internodes well-developed, at least as long as the stipules; stems long and slender, flexuose; flower scapes thin and capilliform.... .................................................................................................................................................................................. 13. D. grantsaui

23’. Internodes very short, leaves forming rosettes; plants acaulescent or, if with long stem, then plants forming stiff columns densely covered with marcescent leaves (except for etiolated plants growing semi-submerged in water); flower scapes usually robust ....... ......................................................................................................................................................................................................... 24

24. Petiole shorter than or equal to one third of total leaf length .......................................................................................................... 25

24’. Petiole longer than one third of total leaf length ............................................................................................................................. 28

25. Basal third of scape exclusively eglandular-pilose or glabrous (glandular trichomes, if present, very sparse).............................. 26

25’. Basal third of scape densely glandular-pilose (eglandular trichomes sparse, if present) ................................................................ 27

26. Basal third of scape densely eglandular-pilose; seeds ovoid, ca. 0.4 mm long........................................................... 8. D. chimaera

26’. Basal third of scape glabrous, or with sparse eglandular trichomes; seeds fusiform, 0.8–1 mm long........................ 18. D. latifolia

27. Plants delicate, acaulescent; leaves decumbent; petiole ≤0.5(–1) mm wide; styles up to 3 mm long ....................... 21. D. montana

27’. Plants robust, often forming stiff columns densely covered in marcescent leaves; leaves semi-erect; petiole ≥ 1.5 mm wide; styles 4–5 mm long................................................................................................................................................... 14. D. graomogolensis

28. Both petiole surfaces densely eglandular-pilose (villous); scapes densely eglandular-pilose (villous) on basal third of length, reducing in density towards the apex ..................................................................................................................................... 31. D. villosa

28’. Abaxial petiole surface glabrescent to densely eglandular-pilose, adaxial surface glabrous to glabrescent; scapes lacking eglandular trichomes or, if present, then very sparse at the base ................................................................................................................. 29

29. Base of scape arcuate (ascending); entire scape densely covered by long (up to 1.8 mm) glandular trichomes decreasing in size towards the apex; seeds ellipsoid .............................................................................................................................. 2. D. ascendens

29’. Base of scape erect; lower half of scape glabrous to glabrescent, tiny glandular trichomes increasing in density towards the apex; seeds fusiform or obconical............................................................................................................................................................. 30

30. Petiole equal to or longer than the lamina, as well as distinct from it, narrower; seeds obconical; endemic to the Chapada Diamantina, Bahia ..................................................................................................................................................................... 23. D. riparia

30’. Petiole shorter than the lamina, grading into it and of near equal width; seeds fusiform; from South and Southeastern Brazil......... ..................................................................................................................................................................................... 18. D. latifolia

31. Stipules divided into multiple laciniate segments from the base; petals white; plants drying black; from montane elevations in Amazonas and Roraima ............................................................................................................................................ 16. D. hirticalyx

31’. Stipules entire up to ca. half their length, then fimbriate, or divided into three unequal segments, of which the lateral are longer and laciniate while the central are shorter and fimbriate; petals pink; plants drying brown; from south of the Amazon Basin ........... 32

32. Leaves obovate-cuneate to cuneate, with geniculate vernation; apical tentacles conspicuously distinct (unifacial marginal glands, with flattened rectangular gland heads), 4–9 mm long .......................................................................................... 29. D. tentaculata

32’. Leaves obovate, oblanceolate or oblong-spatulate, with circinate vernation; apical tentacles inconspicuously distinct, up to 5 mm long, with ellipsoid or globose glandular head................................................................................................................................ 33

33. Adaxial petiole surface densely eglandular-pilose; sepals ovate to suborbicular with rounded (subobtuse) apex, in bud forming a pyramidal projection at their adnate bases .............................................................................................................. 28. D. spirocalyx

33’. Adaxial petiole surface glabrous or only sparsely eglandular-pilose; sepals oblong-ovate to narrowly-ovate with acute apex, not forming pyramidal projections as described above ......................................................................................................................... 34

34. Leaves oblong-spatulate; petiole 0.2–0.5(–1) mm wide; glandular trichomes of similar length present throughout the scape; generally flowering from December to March, usually dormant in the dry season............................................................ 21. D. montana

34’. Leaves obovate to oblong-obovate; petiole 0.4–3.0 mm wide; glandular trichomes absent in the basal third of scape, but dense and larger towards the apex; generally flowering from June to September, growing throughout the year ................... 30. D. tomentosa