Croton, Linnaeus (1753:, 1004

Sodré, Rodolfo C., Berry, Paul E. & Da Silva, Marcos J., 2017, The tribe Crotoneae (Euphorbiaceae, Crotonoideae) in the Chapada dos Veadeiros, Goiás, Brazil, Phytotaxa 321 (1), pp. 1-59 : 7-8

Key to the species of Croton occurring in the Chapada dos Veadeiros

1. Trees 2.5–12 m tall.............................................................................................................................................................................2

- Subshrubs or shrubs 0.1–2 m tall.......................................................................................................................................................4

2. Leaf blades narrowly elliptic or oblong, upper surface glabrous; petioles 1.3–2.5 cm long; styles multifid ............2.33. Croton sp.

- Leaf blades ovate to lanceolate, upper surface pubescent; petioles 4–19 cm long; styles 2-fid........................................................3

3. Stems with stellate-porrect trichomes; stipules 2.5–5 mm long; pistillate sepals 1.6–2 × 0.9–1.5 mm, narrowly triangular or lanceolate; styles pubescent; columella with three prominent, smooth lobes............................................................. 2.15. C. gracilipes

- Stems with dendritic-stellate trichomes; stipules 7–12 mm long; pistillate sepals 3–4 × 1.5–1.9 mm, oblong to ovate; styles glabrous; columella lacking prominent, smooth lobes............................................................................................... 2.32. C. urucurana

4. Leaves with glands at the apex of the petiole and/or along the leaf margin.......................................................................................5

- Leaves without glands......................................................................................................................................................................24

5. Leaf margin and pistillate sepals with stipitate-capitate glands.........................................................................................................6

- Leaf margin and pistillate sepals either without glands, or else the leaf margin with sessile or shortly stipitate patelliform glands and the pistillate sepals with ovoid, globose, ellipsoid, subglobose, subulate or papilliform, sessile glands....................................9

6. Petioles without apical glands; leaf blades lanceolate or narrowly elliptic, base acute, obtuse or asymmetric, margin entire ........... ................................................................................................................................................................................. 2.5. C. arirambae

- Petioles with apical glands; leaf blades ovate, widely ovate or oval-lanceolate, base cordate or lightly cordate, margin serrate or crenate.................................................................................................................................................................................................7

7. Stipules and staminate and pistillate bracts without glands; pedicels of pistillate flowers 0.4–1.2 mm long............ 2.2. C. agoensis

- Stipules and staminate and pistillate bracts with stipitate-capitate glands; pedicels of pistillate flowers 5–9 mm long...................8

8. Stems robust; leaf blades 4.5–8.2 cm long, velutinous to pannose, with densely and regularly distributed glands along the margins..............................................................................................................................................................................2.8. C. catariae

- Stems delicate; leaf blades 2.4–4 cm long, shortly tomentose with sparse and smaller glands along the margins .......................................................................................................................................................................................................2.16. C. gracilirameus

9. Petioles with subcylindrical apical glands; pedicels of the pistillate flowers 3.5–6.7 mm long...........................2.13. C. goyazensis

- Petioles with obconic or patelliform apical glands; pedicels of the pistillate flowers 0.1–2 mm long............................................10

10. Stipules with numerous papilliform glands at the base; petioles with 5–10 glands; staminate sepals 3–3.5 mm long ...................................................................................................................................................................................................2.23. C. megalocalyx

- Stipules with few to no glands at the base; petioles with (1)2(4) glands; staminate sepals 0.9–2.5 mm long.................................11

11. Petioles 2.6–7.1 cm long, with obconical apical glands; leaf blades with acuminate apex ............................... 2.21. C. leptobotryus

- Petioles 0.1–2.4 cm long, with sessile or stipitate patelliform apical glands; leaf blades with acute apex......................................12

12. Leaf margins entire or subentire, without glands; columella with three prominent, smooth lobes..................................................13

- Leaf margins serrate or crenate, usually with glands in the sinuses; columella lacking prominent, smooth lobes.........................14

13. Upper surface of leaf blades glabrous or glabrescent, thyrses 7 − 19 cm long ............................................................ 2.6. C. betaceus

- Upper surface of leaf blades with stellate-porrect trichomes, thyrses 1 − 2.5 cm long.................................... 2.30. C. subferrugineus

14. Pistillate flowers with 6 − 8 sepals, staminate sepals united up to half-way......................................................................................15

- Pistillate flowers with 5 sepals, staminate sepals united only at the base........................................................................................16

15. Usually subdecumbent subshrubs; leaf blades oval-lanceolate, elliptic or oblong, base acute or asymmetric; pistillate sepals oblong or lanceolate, margins entire; stamens (13–)17 − 24.......................................................................................... 2.24. C. odontadenius

- Erect subshrubs; leaf blades oval, base obtuse, truncate or lightly cordate; pistillate sepals obovate to oblanceolate, margins serrate; stamens 6 − 11 ........................................................................................................................................................2.26. C. sclerocalyx

16. Leaf margins usually without glands; bracts with pyriform glands.................................................................................................17

- Leaf margins with glands in the sinuses; bracts with globose glands or without glands.................................................................18

17. Upper surface of leaf blades covered by hispid trichomes; bracts with stipitate glands; pistillate sepals unequal.......2.18. C. hirtus

- Upper surface of leaf blades covered by stellate-porrect trichomes; bracts with sessile glands; pistillate sepals subequal .............................................................................................................................................................................................2.12. C. glandulosus

18. Pistillate sepals equal or subequal, usually ovate, pubescent only on the dorsal surface; styles glabrous or glabrescent...............19

- Pistillate sepals unequal, usually obovate, elliptic or oblong, pubescent on both faces; styles densely pubescent.........................21

19. Leaf blades linear to narrowly elliptic; ovary shortly tomentose, covered by stellate trichomes without a porrect central ray .......... ............................................................................................................................................................................ 2.14. C. gracilescens

- Leaf blades oval-lanceolate, oblong or elliptic; ovary hispid, covered by stellate trichomes with a porrect central ray.................20

20. Few-branched subshrubs, under 50 cm tall; stems brownish; styles 4(2)-fid..................................................2.4. C. antisyphiliticus

- Much-branched shrubs or subshrubs often more than 1 m tall; stems yellowish to ferruginous; styles 2-fid.....2.10. C. desertorum

21. Young stems canescent to pinkish; petiolar glands orange to reddish; thyrses 1–2.9 cm long; styles ca. 2 mm long......................... ........................................................................................................................................................................... 2.20. C. inaequilobus

- Young stems greenish, yellowish or ferrugineous; petiolar glands yellowish; thyrses 4–15 cm long; styles 3.5–5 mm long.........22

22. Leaf blades with 2 or 3(–4) pairs of secondary veins, the basal pair of veins surpassing half the length of the blade; seeds not maculate....................................................................................................................................................................2.1. C. abaitensis

- Leaf blades with 4–10 pairs of secondary veins, the basal pair of veins never exceeding half the length of the blade; seeds maculate....................................................................................................................................................................................................23

23. Stems yellowish; petiolar glands sessile, almost always present; staminate bracts 4–7 mm long; pistillate sepals serrate; staminal filaments glabrous..........................................................................................................................................................2.28. C. spica

- Stems canescent-green; petiolar glands usually absent, shortly stipitate when present; staminate bracts 2.1–2.9 mm long; pistillate sepals entire; staminal filaments villous............................................................................................................ 2.25. C. planaltoanus

24. Staminate flowers with linear-oblanceolate petals; pistillate flowers with 3(4) laciniate developed sepals; styles 4-fid.................... ............................................................................................................................................................................. 2.11. C. didrichsenii

- Staminate flowers with oblanceolate, obovate or elliptic petals; pistillate flowers with 5 entire, developed sepals; styles almost always 2-fid......................................................................................................................................................................................25

25. Stamens 10–11; columella lacking prominent, smooth lobes..........................................................................................................26

- Stamens 15–17; columella with three prominent, smooth lobes......................................................................................................27

26. Staminate flowers 3–4 mm long, pedicels 0.9–1.6 mm long, filaments glabrous; pistillate sepals without glands ............................................................................................................................................................................................................2.19. C. horminum

- Staminate flowers 6–12 mm long, pedicels 2.5–8 mm long, filaments villous at the base; pistillate sepals with ovoid or ellipsoid glands.................................................................................................................................................................2.27. C. siderophyllus

27. Leaves with upper surface dark green and glossy, glabrous or sparsely pubescent; styles patent ...................... 2.31. C. subvillosus

- Leaves with upper surface greenish, never glossy, densely pubescent; styles ascending................................................................28

28. Staminate bracts 3.5–6 mm long......................................................................................................................................................29

- Staminate bracts 0.5–2 mm long......................................................................................................................................................30

29. Pistillate sepals 2.7–3.3 × 0.7–1.6 mm, oval to lanceolate; capsules 5–5.5 mm long, covered by subsessile stellate trichomes ....... .................................................................................................................................................................................... 2.3. C. agrarius

- Pistillate sepals 5–10 × 0.3–1 mm, linear or narrowly lanceolate; capsules 7–9 mm long, covered by stipitate stellate trichomes ... ............................................................................................................................................................................. 2.17. C. grandivelus

30. Subshrubs or shrubs 1–1.8 m; pistillate flowers 2.5–3.5 mm long; capsules oblongoid ....................................... 2.29. C. subacutus

- Subshrubs 0.1–0.5 m; pistillate flowers 5–7.5 mm long; capsules subglobose...............................................................................31

31. Stems, leaves and flowers hirsute, covered by stellate trichomes with a well developed porrect central ray; thyrses 0.9–4.2 cm long........................................................................................................................................................................ 2.9. C. cinerascens

- Stems, leaves and flowers shortly tomentose, covered by stellate trichomes with an underdeveloped or sometimes developed porrect central ray; thyrses 5.5–11 mm long.........................................................................................................................................32

32. Petioles 0.5–1(1.5) mm long; leaf blades lanceolate, base obtuse; flowers laxly distributed along the inflorescence axis................................................................................................................................................................................................2.22. C. longifolius

- Petioles 3–9 (16) mm long; leaf blades oblong, oblanceolate or narrowly elliptic, base acute or attenuate; flowers densely distributed along the inflorescence axis.............................................................................................................................2.7. C. campestris