1 Leaves cordate-auriculate at base; leaves clustered in a 'pseudowhorl' near the apex of the twigs.

..2 Leaves glaucous and finely appressed-pubescent beneath; buds and twigs pubescent; [section Macrophylla].

....3 Conelike aggregate fruit (follicetum) 2.5-6.5 cm long, 1.5-4 cm in diameter; leaf blades 17-56 cm long; stamens 170-350; pistils 20-25 (-50); small tree (to 12 m tall); [of Panhandle FL]

....3 Conelike aggregate fruit (follicetum) 5-8 cm long, 5-7 cm in diameter; leaf blades 50-110 cm long; stamens (300-) 350-580; pistils (44-) 50-80; medium to large tree (to 32 m tall); [widespread, but not of Panhandle FL]

..2 Leaves green and glabrous beneath; buds and twigs glabrous; [section Tuliparia].

......4 Stamens 8-15 mm long; leaves (most of them) over 25 cm long; conelike aggregate fruit (follicetum) 6.5-11 (-14) cm long; [of the Mountains and Piedmont]

......4 Stamens 4-8 (-10.5) mm long; leaves (most of them) < 25 cm long; conelike aggregate fruit (follicetum) 3.5-5.5 (-6) cm long; [of the Coastal Plain]

1 Leaves cuneate to rounded (subcordate) at base; leaves distributed along the twigs (or clustered in a 'pseudowhorl' in M. tripetala).

........5 Leaves evergreen, coriaceous in texture, glossy dark green above as if varnished, rusty tomentose or green beneath; [section Magnolia]

........5 Leaves variably evergreen to deciduous, herbaceous or subcoriaceous in texture, medium green above with a slightly glossy or dull finish; glaucous or green beneath.

..........6 Leaves evergreen to deciduous, aromatic when fresh, 8-20 cm long, elliptic, strongly glaucous beneath; [section Magnolia].

............ 7 Leaves evergreen; previous year's stems densely pubescent; mature leaves with pubescent midveins; flowers opening near sundown (2-5 hours later than var. virginiana); medium to large tree, to >20 m tall; [of the Gulf Coast and inland, north and east to s. SC (e. NC?)]

............ 7 Leaves evergreen to deciduous (at least tardily); previous year's stems glabrous; mature leaves with few hairs along the midvein below; flowers opening mid-afternoon; shrub to multi-stemmed small tree, to 10 m (rarely to 15 m) tall; [of the Atlantic Coastal Plain and inland, south and west to s. SC and w. NC]

..........6 Leaves deciduous, non-aromatic, 3-80 cm long, either ovate, obovate, or oblanceolate, green beneath.

............ ..8 Leaves clustered in a 'pseudowhorl' near the apex of the twigs; leaves (15-) 35-50 (-80) cm long; buds glabrous; [native]; [section Rytidospermum].

............ ..8 Leaves distributed along the twigs (or clustered in a 'pseudowhorl'; leaves (5-) 10-30 cm long; buds pubescent.

............ ....9 Leaf base rounded to subcordate (often cuneate to widely cuneate in M. acuminata var. subcordata); leaves 10-30 cm long, broader toward the base; tepals green to yellow; [native]; [section Tulipastrum].

............ ......10 Twigs of the current year pubescent, or at least with persistent hair-bases, petals golden-yellow above, light-yellow below; small tree (rarely larger)

............ ....9 Leaf base cuneate-attenuate; leaf blade obovate or oblanceolate (broader toward the tip); leaves 3-16 cm long; tepals white to pink or purplish; [Asian species, used horticulturally and rarely persistent or weakly establishing]; [section Yulania]

............ ........11 Tepals 12-15 (-18), the outer tepals 1/2 or less as long as the inner tepals; tepals white with reddish blaze

............ ........11 Tepals 6-9, the outer 3 tepals ca. 2/3 as long as the 6 inner tepals; tepals white or pale to dark purplish red

............ ..........12 Tepals 6 (-9), white (or with a faint purplish line near the base)

............ ..........12 Tepals (6-) 9, pale to dark purplish red