1. Plant parasitic on stem of woody host plant ..... VISCACEAE {G6,7,8,9,11,14}
1' Plant rooted in soil, not parasitic
2. Infl a dense spike or a spheric head, or flowers enclosed within a fleshy, hollow receptacle
3. Lvs pinnately compound or modified into linear to oblong or narrowly elliptic, entire, flattened axes without leaflets; fruit a legume — perianth actually of 2 whorls, the calyx easily overlooked ..... FABACEAE (Mimosoideae)
3' Lvs simple, ovate or wider in overall outline, entire, toothed, or palmately lobed; fruit not a legume
4. Infl a hollow receptacle enclosing many tiny flowers; ripened inflorescence an externally smooth, fleshy multiple fruit [a fig]; milky latex present ..... MORACEAE (Ficus)
4' Infl a short, dense spike or a head; ripened pistillate inflorescence an externally roughened spike or spheric head; milky latex present or 0
5. Perianth parts fused into a tube; flowers bisexual ..... ASTERACEAE (2) {G6,7,8,9,14,17}
5' Perianth parts free; flowers unisexual
6. Lf-blade entire to toothed, sometimes irregularly few-lobed, faces glabrous or sparsely short-hairy; ripened pistillate inflorescence a fleshy spike or head; milky latex present; petiole base not expanded, not covering axillary bud; stipules membranous, free, generally early-deciduous ..... MORACEAE {G7,11}
6' Lf-blade ± deeply palmately lobed, the lobes entire or ± toothed, faces densely stellate-tomentose when young; ripened pistillate inflorescence a dry head of long-stiff-hairy achenes; milky latex 0; petiole base expanded, covering axillary bud; stipules large and green, fused around stem, persistent or deciduous — pistils actually > 1 ..... PLATANACEAE {G7,9,10}
2' Infl not a dense spike or a spheric head, flowers not enclosed in a fleshy, hollow receptacle
7. Fls unisexual, plant monoecious; pistillate inflorescence 1–5-flowered, maturing as a bur with spiny, knob-like, or membranous bract tips; staminate inflorescence a head ..... ASTERACEAE (Ambrosia)
7' Fls bisexual, or if unisexual, pistillate inflorescence not 1–5-flowered and maturing as a bur with spiny, knob-like, or membranous bract tips; staminate inflorescence various
8. Ovary inferior, partly so, or appearing so
9. Herbage covered with silvery scales; fruit drupe-like — ovary actually superior, ripening as an achene, tightly enclosed by hypanthium base that becomes fleshy at maturity ..... ELAEAGNACEAE
9' Herbage without silvery scales; fruit various
10. Infl unit an involucred head, superficially resembling a single flower ..... ASTERACEAE (2) {G6,7,8,9,14,17}
10' Infl open or flowers solitary or paired
11. Trees, evergreen; stamens many; leaves aromatic — perianth early-deciduous as cap ..... MYRTACEAE (Eucalyptus)
11' Shrubs or woody vines, evergreen or deciduous; stamens 4–12; leaves generally not aromatic
12. Perianth rotate, lobes >> tube; leaves whorled; fruit 2-lobed ..... RUBIACEAE (Galium) {G6,7,8,9}
12' Perianth tubular, lobes << tube; leaves alternate or opposite; fruit not lobed
13. Lvs alternate; perianth tube U-shaped; twining vine ..... ARISTOLOCHIACEAE (Aristolochia)
13' Lvs opposite; perianth tube straight; erect shrub ..... CAPRIFOLIACEAE (Lonicera involucrata)
8' Ovary superior
14. Lvs opposite or whorled
15. Fr winged, indehiscent; leaves generally lobed or compound
16. Style evident, stigma 1, entire or slightly 2-lobed; fruit 1-winged, not splitting; leaves pinnately compound (leaflet generally 1 in Fraxinus anomala) ..... OLEACEAE (Fraxinus) {G7,9,16}
16' Style very short, stigmas 2(3), elongate; fruit 2(3)-winged, generally splitting into mericarps; leaves palmately lobed or compound or pinnately compound ..... SAPINDACEAE (Acer) {G7,23}
15' Fr not winged; leaves simple, entire or toothed
17. Fls bisexual; stamens 20–25(30) ..... ROSACEAE (Coleogyne)
17' Fls unisexual; stamens generally 3–12
18. Lf covered with silvery scales ..... ELAEAGNACEAE (Shepherdia) {G7,9}
18' Lf glabrous or ± hairy
19. Lvs needle-like, abaxially grooved ..... ERICACEAE (Empetrum) (2) {G7,9,16}
19' Lvs not needle-like, not grooved
20. Staminate and pistillate flowers in sessile umbels; style 1, stigma entire or 2-lobed ..... OLEACEAE (Forestiera) {G7,9}
20' Staminate flowers clustered, pistillate flowers generally solitary; styles or stigmas (2)3–5
21. Staminate inflorescence a raceme or panicle, flowers clearly stalked; fruit 3–4-lobed ..... PICRODENDRACEAE {G7,9}
21' Staminate inflorescence head-like, flowers subsessile; fruit unlobed ..... SIMMONDSIACEAE {G7,9}
14' Lvs alternate
22. Lvs pinnately compound or very deeply pinnately divided
23. Perianth parts ± brown-green, inconspicuous, bract-like; flowers unisexual, plants dioecious ..... ANACARDIACEAE (Pistacia) {G7,11}
23' Perianth parts petal-like, conspicuous; flowers bisexual
24. Shrub; flowers solitary; perianth radial, parts 6, white — sepals actually present in bud, but early-deciduous, 0 in open flower ..... PAPAVERACEAE (Romneya) {G22}
24' Tree; flowers in raceme; perianth bilateral, parts 4, yellow or orange, proximally ± red ..... PROTEACEAE
22' Lvs simple, sometimes lobed
25. Infl flower-like with a cup-like involucre bearing colored, often petal-like nectaries; each stamen [actually a staminate flower] with a jointed stalk [composed of a filament and a pedicel]; pistil [actually pistillate flower] 3-lobed, generally exserted from involucre; milky latex present ..... EUPHORBIACEAE (Euphorbia)
25' Infls various, but not flower-like; stamens generally > 1 per flower, the filaments not jointed; pistils various; milky latex generally 0
26. Anthers opening by pores with hinged lids; leaf strongly aromatic — 2-whorled nature of perianth may not be evident in open flowers ..... LAURACEAE {G16}
26' Anthers opening by slits; leaf generally not aromatic
27. Lvs fleshy, cylindric to ± flat ..... CHENOPODIACEAE (Suaeda)
27' Lvs not fleshy, generally flat
28. Lf palmately veined and lobed
29. Woody vine; tendrils present — calyx 0 or reduced to an entire or slightly lobed rim, easily overlooked ..... VITACEAE (Vitis) {G7,9,23}
29' Erect or spreading shrub; tendrils 0
30. Lf peltate, glabrous; flowers unisexual, perianth parts ± green, free; stamens very many, the filaments irregularly joined in clusters ..... EUPHORBIACEAE (Ricinus) {G7,9}
30' Lf not peltate, stellate-hairy; flowers bisexual, perianth parts yellow or orange to ± red, petal-like; stamens 5, filaments fused in 1 group ..... MALVACEAE (Fremontodendron) {G19}
28' Lf pinnately veined or only midvein evident, generally unlobed
31. Perianth parts 2–3 cm, bright yellow; ovules many — sepals actually present in bud, but early-deciduous, 0 in open flower ..... PAPAVERACEAE (Dendromecon)
31' Perianth parts generally < 1.5 cm, generally not yellow and petal-like; ovules 1–2 per chamber
32. Plant covered with ± gray or silvery scales
33. Fls tubular in proximal half, some or all bisexual; tree or large shrub; leaves linear-lanceolate to oblong ..... ELAEAGNACEAE (Elaeagnus)
33' Fls not tubular, all unisexual, plant dioecious; shrub; leaves various
34. Ovary of pistillate flower enclosed by 2 appressed bracts; leaf surface scales powder-like, not stellate ..... CHENOPODIACEAE (Atriplex) {G6,8}
34' Ovary of pistillate flower subtended by 5 sepals; leaf surface scales stellate ..... EUPHORBIACEAE (Croton) {G6,8}
32' Plant without scales
35. Perianth parts 6 — 2-whorled nature of perianth may not be evident in open flowers
36. Fls solitary, axillary, unisexual; fruit a berry ..... ERICACEAE (Empetrum) (2) {G7,9,16}
36' Fls in involucred umbels, bisexual; fruit an achene ..... POLYGONACEAE (Eriogonum) {G6,8}
35' Perianth parts generally 4 or 5
37. Stamens = in number to and alternate sepals ..... RHAMNACEAE {G21,23}
37' Stamens = in number to and opposite sepals or > in number than sepals
38. Style and stigma 1
39. Style feathery with long, stiff hairs; fruit an achene surrounded by a tubular hypanthium; branches stiff ..... ROSACEAE (Cercocarpus)
39' Style glabrous; fruit an exposed drupe; branches pliable — corolla 0 or reduced to minute scales, easily overlooked ..... THYMELAEACEAE
38' Styles or stigmas 2–4
40. Fr a drupe; flowers staminate and bisexual ..... CANNABACEAE (Celtis) {G7}
40' Fr a winged nutlet or splitting into 1–2-seeded segments that release seeds; flowers unisexual or bisexual
41. Tree; fruit a flattened, round to ovate, 2-winged nutlet ..... ULMACEAE
41' Shrub; fruit splitting into segments
42. Lvs elliptic, crenate; fruit segments 1-seeded ..... EUPHORBIACEAE (Bernardia)
42' Lvs oblanceolate to obovate, entire; fruit segments 1–2-seeded ..... PICRODENDRACEAE (Tetracoccus hallii)
