1. Plant parasitic on stem of woody host plant ..... VISCACEAE {G6,8,9,11,12,14}
1' Plant free-living, rooted in ground
2. Trunk unbranched, generally stout, covered with persistent woody leaf bases; leaves 4–7 m, pinnately compound ..... ARECACEAE (Phoenix) {G9,10}
2' Trunk(s) generally branched, stout or slender, generally not covered with persistent leaf bases; leaves generally smaller, simple or compound
3. Lvs stiff and sword-like, 0.6–2 m, base much expanded, white, fleshy; inflorescence a large panicle ..... RUSCACEAE (Nolina) {G6,8,9,16}
3' Lvs not sword-like, mostly smaller, base not much expanded, white, and fleshy; inflorescences various
4. Lvs opposite or whorled
5. Lvs compound
6. Lvs palmate ..... SAPINDACEAE
6' Lvs pinnate
7. Woody vine; sepals generally 4, conspicuous, petal-like ..... RANUNCULACEAE (Clematis) {G9}
7' Tree or large shrub; sepals generally 5 or number difficult to determine, very small
8. Fls sessile or borne on short, stout pedicels ..... OLEACEAE (Fraxinus) {G9,12,16}
8' Fls borne on elongated, thread-like pedicels ..... SAPINDACEAE (Acer negundo) {G9}
5' Lvs simple
9. Lf toothed or lobed
10. Lf palmately veined and lobed ..... SAPINDACEAE (Acer) {G12,23}
10' Lf pinnately veined and toothed
11. Petals 0; stamens 4–10 ..... PICRODENDRACEAE (4) {G9,12}
11' Petals 5, united in salverform corolla; stamens 4, epipetalous ..... SCROPHULARIACEAE (Buddleja) (2) {G9,19}
9' Lf entire (strongly wavy in some Garrya species)
12. Infl a catkin
13. Lf blades well developed; catkins elongate, pendent ..... GARRYACEAE {G9,11}
13' Lvs scale-, awl-, or needle-like; "catkins" short, not pendent — actually catkin-like pollen cone of gymnosperm
14. Internodes very short; stem concealed by persistent, overlapping, green, scale-, awl-, or needle-like leaves; pollen sacs sessile beneath scales of small cone ..... CUPRESSACEAE (2) {G4}
14' Internodes long; stem green, bearing dry, scale-like, often early-deciduous leaves; pollen sacs borne on filament-like stalk ..... EPHEDRACEAE {G4,9}
12' Infl not a catkin
15. Lvs whorled
16. Lf with abaxial groove ..... ERICACEAE (Empetrum) (2) {G9,12,16}
16' Lf flat or with midvein raised on abaxial face
17. Stamens 4; weak-stemmed shrub; stems 4-angled when young ..... RUBIACEAE (Galium) {G6,8,9,12}
17' Stamens 5–10; stiff shrub; stems round ..... PICRODENDRACEAE (4) {G9,12}
15' Lvs opposite
18. Herbage covered with silvery scales ..... ELAEAGNACEAE (Shepherdia) {G9,12}
18' Herbage glabrous or variously hairy
19. Petals fused proximally; stamens fused to corolla
20. Lvs glossy ..... RUBIACEAE ([Coprosma]) {G9}
20' Lvs densely hairy ..... SCROPHULARIACEAE (Buddleja) (2) {G9,19}
19' Petals free or 0; stamens free from corolla
21. Lvs thick, leathery, evergreen; flowers in peduncled, head-like clusters; sepals well developed ..... SIMMONDSIACEAE {G9,12}
21' Lvs thin, deciduous; flowers in sessile axillary clusters or short-peduncled racemes; sepals very small
22. Bark of young stems ± red; flowers pedicelled in short axillary racemes; stamens 5–10 ..... PICRODENDRACEAE (4) {G9,12}
22' Bark of young stems gray; flowers ± sessile in axillary clusters; stamens 1–4 ..... OLEACEAE (Forestiera) {G9,12}
4' Lvs alternate (leaf often opposite a tendril or inflorescence in Vitaceae)
23. Tendrils present; plant a vine; inflorescence of umbels or a panicle of head- or umbel-like clusters
24. Tendrils each opposite a leaf; calyx 0 or 5-lobed; petals 5, adherent at tips, ± yellow ..... VITACEAE (Vitis) {G9,12,23}
24' Tendrils 2+ near petiole base; perianth parts 6 in 2 whorls of 3, petal-like, free, white to ± green or ± yellow ..... SMILACACEAE {G6,8,9,16}
23' Tendrils 0; plant a shrub or tree, rarely a vine; inflorescence various
25. Infl a catkin or spike
26. Lvs compound
27. Lvs 1- and 2-pinnate, leaflets 20–28 on 1-pinnate leaves ..... FABACEAE (Gleditsia) {G9}
27' Lvs 1-pinnate, leaflets 5–21
28. Plant evergreen — inflorescence resembles catkin when young, but is actually a branched panicle ..... ANACARDIACEAE (Pistacia) {G11,12}
28' Plant deciduous ..... JUGLANDACEAE {G9,11}
26' Lvs simple
29. Shrubs of ± saline desert habitats; leaves sometimes thick, ± fleshy; spikes erect or very short and axillary
30. Lf blades generally flat; perianth present though generally small and inconspicuous; bracts 0 or not peltate ..... CHENOPODIACEAE (2) {G6,8,9,11,15}
30' Lf blades generally ± cylindric; perianth 0; bracts peltate ..... SARCOBATACEAE {G9,11}
29' Shrubs or trees, generally of non-saline habitats; leaves mostly thinner, not fleshy; spikes or catkins erect to pendent
31. Lvs scale-, awl- or needle-like; plants evergreen — catkin-like structure actually pollen cone of a gymnosperm
32. Pollen sacs borne on filament-like stalks ..... TAXACEAE {G4}
32' Pollen sacs sessile on abaxial side of scale-like structures
33. Scales with 2 pollen sacs; needle-like leaves 1–30 cm; bark generally separating in flakes or plates ..... PINACEAE {G4}
33' Scales with several pollen sacs; needle-like leaves (if present) 1–2.5 cm; bark thick, fibrous, persistent ..... CUPRESSACEAE (2) {G4}
31' Lvs with well developed blades; plants evergreen or deciduous
34. Bractlets of inflorescence well developed and readily visible at time of flower
35. Catkins pendent
36. Catkin-bractlets fringe-margined, early-deciduous; stamens 8–60; trees ..... SALICACEAE (Populus)
36' Catkin-bractlets entire or appearing 3-lobed, persistent; stamens 1–10; shrubs or trees ..... BETULACEAE {G9,11}
35' Catkins ± stiff, ± erect to spreading but generally not pendent
37. Low, brittle shrubs; leaves thin, crenate ..... EUPHORBIACEAE (Acalypha) {G9,11}
37' Shrubs or trees, not brittle; leaves entire or toothed — catkin bracts sometimes early-deciduous ..... SALICACEAE (Salix)
34' Bractlets of inflorescence 0 or very inconspicuous at time of flower
38. Evergreen shrubs or trees
39. Main veins of leaf parallel or nearly so — 2 perianth whorls actually present but sepals small and easily overlooked ..... FABACEAE (Acacia) (2)
39' Main veins of leaf clearly pinnate
40. Lvs glabrous or with stellate hairs, not gland-dotted; sepals present; generally of dry-land habitats; catkins slender, pendent, generally >= 2 cm ..... FAGACEAE (2) {G9,11}
40' Lvs glabrous or with minute, straight hairs, dotted with tiny resin glands; sepals 0; generally of moist, often wetland habitats; catkins short, dense, generally < 2 cm ..... MYRICACEAE (2) {G9,11}
38' Deciduous shrubs or trees
41. Sepals small but evident
42. Sepals 5–7; stamens 5–20; veins pinnate; leaf bases generally symmetric ..... FAGACEAE (2) {G9,11}
42' Sepals 4; stamens 4; veins palmate; leaf bases oblique ..... MORACEAE {G11,12}
41' Sepals 0 or calyx modified into cup- or saucer-shaped structure or reduced to a nectary
43. Lvs dotted with tiny resin glands; individual flowers difficult to distinguish ..... MYRICACEAE (2) {G9,11}
43' Lvs not gland-dotted; individual flowers clearly distinguishable on close examination ..... SALICACEAE {G9,11}
25' Infl not a catkin or spike
44. Lvs and stems armed with prickles
45. Petals free; stamens many ..... ROSACEAE (Rubus ursinus) {G9}
45' Petals fused; stamens 5 ..... SOLANACEAE (Solanum marginatum)
44' Foliage not prickly, sometimes stems thorny or leaves spiny-toothed
46. Lvs palmately lobed
47. Lvs peltate; inflorescence a panicle ..... EUPHORBIACEAE (Ricinus) {G9,12}
47' Lvs not peltate; inflorescence a head ..... PLATANACEAE {G9,10,12}
46' Lvs not palmately lobed
48. Sts and leaves densely covered with stellate hairs ..... EUPHORBIACEAE {G9,15}
48' Sts and leaves glabrous or hairy but hairs not stellate
49. Stamens many
50. Lvs strongly aromatic; sepals 4; petals 0; anthers dehiscing by uplifted lids ..... LAURACEAE ([Laurus]) (2) {G9}
50' Lvs not aromatic; sepals 5; petals 5; anthers dehiscent by slits
51. Fls in spheric heads; petals yellow, generally concealed by stamens; leaves simple or 2-pinnate ..... FABACEAE (Acacia) (2)
51' Fls in racemes; petals white, conspicuous; leaves simple ..... ROSACEAE (Oemleria) {G9}
49' Stamens 12 or fewer
52. Lvs compound
53. Lflets with a few, gland-tipped teeth near base ..... SIMAROUBACEAE (Ailanthus) {G9,10,20}
53' Lflets entire or teeth not gland-tipped
54. Lflets 3–20, lance-linear to ovate, 10–130 mm ..... ANACARDIACEAE (2) {G9,20,23}
54' Lflets 7–33, linear-oblong or narrowly elliptic, 2–10 mm ..... BURSERACEAE {G9,20}
52' Lvs simple (occasionally reduced to scales)
55. Shrub with thorny, generally leafless green stems; leaves scale-like to narrowly oblong, early deciduous ..... SIMAROUBACEAE (Castela) {G9,10,23}
55' Tree, shrub, or woody vine, thorns occasionally present but stems generally leafy; leaves various, sometimes deciduous in winter or dry season
56. Fl parts in 3s — leaves with abaxial groove ..... ERICACEAE (Empetrum) (2) {G9,12,16}
56' Fl parts generally in 4s, 5s, or 6s
57. Fls in involucred heads, these generally in few- to many-headed clusters ..... ASTERACEAE {G6,8,9,12,14,17}
57' Fls solitary or variously clustered, not in involucred heads
58. Lvs generally ± gray, either softly hairy or covered with powdery scales ..... CHENOPODIACEAE (2) {G6,8,9,11,15}
58' Lvs green
59. Petals present
60. Lvs entire to lobed, not spiny-toothed; inflorescence a terminal or axillary panicle or umbel-like cluster, or flowers 1; flower parts generally in 5s
61. Petals 1–5 mm ..... ANACARDIACEAE (2) {G9,20,23}
61' Petals 10–15 mm ..... PITTOSPORACEAE (Pittosporum)
60' Lvs spiny-toothed or entire; inflorescence an axillary cyme; flower parts in 4s or 5s
62. Stamens generally 4, alternate petals ..... AQUIFOLIACEAE {G9}
62' Stamens 4–5, opposite petals ..... RHAMNACEAE (Rhamnus) (2) {G9}
59' Petals 0
63. Lvs strongly aromatic; anthers dehiscing by uplifted lids ..... LAURACEAE ([Laurus]) (2) {G9}
63' Lvs not aromatic; anthers dehiscent by slits
64. Stamens = in number to and alternate sepals ..... RHAMNACEAE (Rhamnus) (2) {G9}
64' Stamens = in number to and opposite sepals or > in number than sepals
65. Lf blade 2–12 mm; shrubs ..... PICRODENDRACEAE (4) {G9,12}
65' Lf blade 30–140 mm; trees or large shrubs
66. Lf 3-veined from base; inflorescence a sessile axillary cluster ..... CANNABACEAE (Celtis) {G12}
66' Lf 1-veined from base; inflorescence a stalked umbel or umbel-like raceme ..... MORACEAE (Maclura) {G9}
