Draba L.

1a. Flowering stem with 0 leaves; flowers without subtending bracts; stem unbranched. … 2

1b. Flowering stem with 1 to many leaves; flowers with or without subtending bracts; stem branched or unbranched … 34

2a. Underside of leaf surface either glabrous or with simple to 2–6 rayed trichomes; fruits flattened or inflated basally; fruits planar. … 3

2b. Underside of leaf surface predominately pubescent with stellate, 6–12 rayed; fruits flattened and not inflated; fruits planar to slightly twisted … 22

3a. Underside of leaf surface glabrous or with at least both simple and multi-branched trichomes; flowering stem pubescent or glabrous. … 4

3b. Underside of leaf surface without simple trichomes, exclusively with 2–6 rayed trichomes; flowering stem pubescent … 15

4a. Flowers white … 5

4b. Flowers yellow … 8

5a. Fruit surface hairy with 5–12 rayed trichomes; midvein not prominent or noticeable and not persistent … Draba oblongata

5b. Fruit surface glabrous; midvein prominent and thickened on underside of leaves … 6

6a. Plants densely cespitose, pulvinate … Draba subcapitata

6b. Plants not pulvinate … 7

7a. Underside of leaf glabrous or simple and 2rayed trichomes; petal length 2–2.5 mm … Draba fladnizensis

7b. Underside of leaf glabrous or with multibranched trichomes concentrated toward leaf tip; petal length 3–5 mm … Draba lactea

8a. Flowering stem, rachis, and pedicels glabrous … 9

8b. Flowering stem, rachis, and pedicels hairy … 12

9a. Upper leaf surface glabrous except for ciliate margins … 10

9b. Upper leaf surface hairy … 11

10a. Pulvinate; fruit surface hairy with simple or 2–5 rayed trichomes; petal length 2–5 mm; leaves not fleshy … Draba densifolia

10b. Not pulvinate; fruit surface glabrous; petal length 1.5–2.5 mm; leaves fleshy … Draba crassifolia

11a. Leaves with simple and 2 rayed trichomes; petal length 1.5–2.5 mm; fruit surface glabrous … Draba crassifolia

11b. Leaves with simple and 2-4 rayed trichomes; petal length 3.5–6 mm; fruit surface hairy or glabrous … Draba pilosa

12a. Midvein prominent and thickened on underside of leaves … 13

12b. Midvein not prominent or noticeable and not persistent … 14

13a. Lowest fruit pedicel length 6–13 mm; petals 3.5–4 mm; anther height 0.4–0.5 mm … Draba pilosa

13b. Lowest fruit pedicel length 1.5–4 mm; petals 2.5–6 mm; anther height 0.2–0.3 mm … Draba pauciflora

14a. Leaf and flowering stem glabrous or with simple to few 2 rayed trichomes; petals yellow to pale green-purple, 0.5–0.8 mm wide; westernmost Alaska … Draba aleutica

14b. Leaf and flowering stem with 2–5 rayed trichomes; petals yellow, 0.3–0.7 mm wide … Draba stenopetala

15a. Fruit surface hairy … 16

15b. Fruit surface glabrous … 20

16a. Fruit surface with 2–6 rayed trichomes; leaf margin not ciliate … Draba ventosa

16b. Fruit surface with simple trichomes, leaf margins ciliate … 17

17a. Upper leaf surface glabrous or with only simple trichomes … 18a

17b. Upper leaf surface with simple and at least some branched trichomes … 19

18a. Plant cespitose; lower half of filaments obviously inflated; petal length 3.5–4 mm … Draba healyi

18b. Not cespitose; filaments slender throughout; petal length 2–3 mm … Draba micropetala

19a. Petals 2.5–3 mm; stigma wide as style; simple and Y-shaped spreading trichomes on flowering stem and leaf surfaces … Draba bennettii

19b. Petals 4–6 mm; stigma obviously wider than style; simple and/or stalked 2–5 rayed trichomes on flower stem and leaf surfaces … Draba corymbosa

20a. Lower half of filaments obviously inflated; upper leaf surface with only simple trichomes … Draba healyi

20b. Filaments slender throughout; upper leaf surface glabrous or with simple and 2–4 rayed trichomes. … 21

21a. Lowest fruit pedicels 1.5–4.5 mm; ovules 10–14; fruits inflated basally; petals pale yellow … Draba macounii

21b. Lowest fruit pedicels 5–17 mm; ovules 16–30; fruits not inflated; petals pale yellow to creamy white … Draba juvenilis

22a. Fruit surface hairy … 23

22b. Fruit surface glabrous, without trichomes, or if present then only on replum … 28

23a. Flowers yellow … 24

23b. Flowers white … 26

24a. Lower leaf surface with 2–10 rayed, stellate trichomes … Draba ruaxes

24b. Lower leaf surface with comb-like trichomes, sometimes 4–6 rayed trichomes present … 25

25a. Midevein not prominent or noticeable underside of basal leaves; petal length 4–6 mm; fruit length 5–9 mm; flowering stem with simple and 2–5 rayed trichomes, sometimes with comb-like trichomes … Draba incerta

25b. Underside of older basal leaves with a prominent or thickened midvein; petal length 2.5–4 mm; fruit length 3–6 mm; flowering stem with comb-like trichomes … Draba oligosperma

26a. Fruit trichomes simple and 2 rayed; fruit length 6–15 mm; ovules 16–24; petal length 2–3.5 mm; stem glabrous to pubescent … Draba lonchocarpa

26b. Fruit trichomes 2–15 rayed; fruit length 4–8 mm; ovules 20–36; petal length 3.5–5 mm; stem pubescent … 27

27a. Fruit trichomes 2–4 rayed; anther height 0.3–0.4 mm; basal leaf surface with short stalked stellate 8–12 rayed trichomes; basal leaf entire or with single tooth on sides; caudex simple or branched … Draba cinerea

27b. Fruit trichomes 5–12 rayed; anther height 0.2–0.3 mm; basal leaf surface with simple and stalked 2–3 rayed trichomes and short stalked 8–12 rayed trichomes; basal leaf margins entire; caudex branched … Draba oblongata

28a. Flowering stem and pedicels pubescent with stellate trichomes; fruits slightly twisted or planar; cespitose … 29

28b. Flowering stem and pedicels glabrous or pubescent toward the base; fruits planar; cespitose or not … 30

29a. Fruits elliptic to oblong-elliptic; fruit length 3.5–9 mm; fruit surface glabrous, but sometimes with 3–6 rayed trichomes on the replum … Draba nivalis

29b. Fruits narrowly lanceolate or oblong; fruit length 9–15 mm … Draba lonchocarpa

30a. Underside of older basal leaves have a prominent or thickened midvein … Draba lactea

30b. Midvein not prominent or noticeable underside of basal leaves … 31

31a. Upper leaf surface with 8–12 branched trichomes … 32

31b. Upper leaf surface glabrous or with 2–4 branched trichomes … 33

32a. Petals 4.5–5.5 mm; ovules 12–16 … Draba mulliganii

32b. Petals 3.2–4 mm; ovules 18–32 … Draba palanderiana

33a. Fruits 4–8 mm; flowering stem trichomes 3–5 rayed … Draba porsildii

33b. Fruits 10–18 mm; flowering stem trichomes 8–12 rayed … Draba lonchocarpa

34a. Underside of leaf surface glabrous or with simple to predominately 2–6 rayed trichomes … 35

34b. Underside of leaf surface hairy with predominately stellate, or 6–12 rayed trichomes … 46

35a. Fruit surface hairy … 36

35b. Fruit surface glabrous … 39

36a. Rachis glabrous; petals yellow … Draba nemorosa

36b. Rachis hairy; petals white … 37

37a. Fruit surface very hairy with 5–12 rayed trichomes … Draba oblongata

37b. Fruit surface hairy with simple and/or 2–4 rayed trichomes … 38

38a. Petal length 2.8–3.5 mm, 0.6–1.5 mm wide; ovule number 35–52; anther height 0.2–0.3 mm; fruits planar … Draba praealta

38b. Petal length 4–6 mm, 2–3 mm wide; ovule number 16–28; anther height 0.3–0.5 mm; fruits twisted or planar … Draba borealis

39a. Flowers white, creamy white, or very faint pale yellow … 40

39b. Flowers yellow … 42

40a. Flowering stem glabrous; lower leaf surface usually glabrous or with simple trichomes if present; lowest pedicel length 2–6 mm … Draba fladnizensis

40b. Flowering stem pubescent; lower leaf surface with cruciform or 2-rayed trichomes; lowest pedicel length 5–18 mm … 41

41a. Leaf margins ciliate; leaf margin entire; flowers white; style 0.6–1.5 mm long … Draba murrayi

41b. Leaf margins not ciliate; leaf margin entire or denticulate; flowers creamy white to pale yellow; style 0.2–0.7 mm long … Draba juvenilis

42a. Stolons or leafy stolons present … Draba ogilviensis

42b. Stolons absent … 43

43a. Perennial with well-developed thickened caudex, stems decumbent … Draba grandis

43b. Annual or biennial with non-prominent taproot or fibrous roots, without a well-developed caudex … 44

44a. Fruiting pedicels long (7–28 mm), longer than fruits … Draba nemorosa

44b. Fruiting pedicels short (3–14 mm), subequal or shorter than fruits … 45

45a. Fruits 6–12 mm; lower half of flowering stem and upper leaf surface with both simple and 2 rayed trichomes … Draba albertina

45b. Fruits 10–17 mm; lower half of stem and upper leaf surface without simple trichomes but with 2–4 rayed trichomes … Draba stenoloba

46a. Lowest flowers with subtending bracts … 47

46b. Flowers without subtending bracts … 51

47a. Flowers yellow … Draba aurea

47b. Flowers white … 48

48a. Fruit surface glabrous … 49

48b. Fruit surface hairy … 50

49a. Upper leaf surface with stellate, 8–12 rayed trichomes; ovules 16–20; anther height 0.2–0.3 mm; petal length 2–3.5 mm; rachis pubescent; fruits planar … Draba chamissonis

49b. Upper leaf surface glabrous or with simple trichomes; ovules 24–36; anther height 0.3–0.5 mm; petal length 4–5.5 mm; rachis glabrous; fruits planar or slightly twisted … Draba glabella

50a. Rachis pubescent; flower number 15–47; lowest pedicel length 2–5 mm; sepals 1.5–2 mm … Draba cana

50b. Rachis glabrous; flower number 3–9; lowest pedicel length 3–10 mm; sepals 2–3.5 mm … Draba glabella

51a. Fruit glabrous … 52

51b. Fruit with trichomes, or valve surface glabrous but with hairs present on replum … 54

52a. Petal length 4–5.5 mm; cauline leaf number 2–17; ovule number 24–36; caudex simple or branched … Draba glabella

52b. Petal length 2–4 mm; cauline leaf number usually not more than 1; ovule number 12–24; caudex branched … 53

53a. Fruit length 6–18 mm; ovule number 16–28 … Draba lonchocarpa

53b. Fruit length 4–7.5 mm; ovule number 12–16 … Draba porsildii

54a. Fruit trichomes 2–5 rayed or if surface glabrous then with 3–6 rayed trichomes on the replum … 55

54b. Fruit valve surface with both simple and 2–5 rayed trichomes … 56

55a. Fruit surface glabrous except for hairs on the replum; petal length 2.5–3.5 mm; lowest pedicel length 1–4.5 mm … Draba nivalis

55b. Fruit surface with dense stellate trichomes; petal length 3.5–4.5 mm; lowest pedicel length 4–7 mm … Draba cinerea

56a. Leaf blade margins dentate or denticulate; cauline leaf number 2–17; fruits planar … Draba glabella

56b. Leaf blade margins entire; cauline leaf number 1–2; fruits planar or slightly twisted … Draba lonchocarpa