=A. Parts of the flower nearly always in threes;
leaves almost always parallel-veined.=
a. Ovary superior.
b. Leaves often arrow-shaped; pistils many, in a head.
_Alismaceae_ 2
b. Leaves not arrow-shaped; pistil one. _Liliaceae_ 4
a. Ovary inferior
b. Flowers regular; stamens three. _Iridaceae_ 66
b. Flowers irregular; stamens one or two. _Orchidaceae_ 72
=A. Parts of the flower mostly in fours or fives;
leaves mostly netted-veined.=
=B. Corolla absent; calyx mostly present, sometimes
showy.=
a. Ovary superior.
b. Pistils several to many, distinct. _Ranunculaceae_ 126
b. Pistil one, one to several-celled.
c. Flowers in long spikes with a white involucre
at base. _Saururaceae_ 80
c. Flowers not in long spikes.
d. Stipules if present sheathing the stem;
sepals three to six. _Polygonaceae_ 86
d. Stipules absent; sepals mostly five.
_Chenopodiaceae_ 96
a. Ovary inferior or appearing so by the closely fitting
calyx.
b. Ovary six-celled; stamens six to twelve.
_Aristolochiaceae_ 84
b. Ovary one-celled; stamens three to five.
c. Leaves opposite; flowers often showy.
_Nyctaginaceae_ 100
c. Leaves alternate; flowers not showy.
_Santalaceae_ 82
=B. Both corolla and calyx present.=
=C. Corolla of separate petals.=
=D. Ovary superior.=
a. Stamens more than ten in number.
b. Pistils several to many, separate or
united below.
c. Pistils separate and distinct.
d. Pistils enclosed in a hollow receptacle.
e. Leaves opposite; petals numerous.
_Calycanthaceae_ 158
e. Leaves alternate; petals mostly
five. _Rosaceae_ 218
d. Pistils not enclosed in a receptacle.
e. Stamens attached to the
calyx. _Rosaceae_ 218
e. Stamens not attached to the
calyx. _Ranunculaceae_ 126
c. Pistils united below into a lobed or
beaked ovary.
d. Water plants with floating leaves.
_Nymphaceae_ 156
d. Terrestrial or land plants.
e. Pistils forming a ring; filaments
united. _Malvaceae_ 284
e. Pistils not forming a ring.
f. Pistils inserted on a convex
receptacle; stamens attached
to the calyx. _Rosaceae_ 218
f. Receptacle not convex; stamens
not attached to the
calyx. _Papaveraceae_ 160
b. Pistil one, the styles and stigmas often
several.
c. Ovary one-celled.
d. Style and stigma one.
e. Fruit a drupe (stone-fruit.)
_Drupaceae_ 216
e. Fruit an akene tipped with a
tail. _Rosaceae_ 218
d. Styles or stigmas more than one.
e. Sepals falling as the flowers
expand.
f. Sepals two or three; fruit
a capsule. _Papaveraceae_ 160
f. Sepals four or six; fruit a
berry. _Ranunculaceae_ 126
e. Sepals persistent; low shrubs.
_Cistaceae_ 304
c. Ovary more than one-celled.
d. Water plants with floating leaves.
_Nymphaceae_ 156
d. Plants not growing in water.
e. Leaves with smooth margins
and with transparent dots.
_Hypericaceae_ 292
e. Leaves neither smooth-edged,
nor with transparent dots.
_Malvaceae_ 284
a. Stamens ten or fewer in number.
b. Stamens of the same number as the
petals and opposite them.
c. Ovary more than one-celled; calyx
four- to five-cleft. _Rhamnaceae_ 282
c. Ovary one-celled.
d. Anthers opening by uplifted
valves. _Berberidaceae_ 152
d. Anthers opening by longitudinal
slits. _Portulacaceae_ 120
b. Stamens not of the same number as the
petals, or if of the same number, alternate
with them.
c. Ovaries two or more, separate or
partly united.
d. Stamens united with each other
and with the large thick stigma.
_Asclepiadaceae_ 374
d. Stamens free from each other
and from the pistils.
e. Stamens inserted on the
receptacle.
f. Leaves and stems fleshy.
_Crassulaceae_ 192
f. Leaves and stems not
noticeably fleshy.
g. Lobes of ovary two to
five, with a common
style.
h. Ovary two- to three-lobed.
_Limnanthaceae_ 278
h. Ovary five-lobed.
_Geraniaceae_ 274
g. Ovaries with separate
styles. _Ranunculaceae_ 126
e. Stamens inserted on the
calyx.
f. Stamens twice as many as
the pistils. _Crassulaceae_ 192
f. Stamens not twice as many
as the pistils.
g. Stipules present. _Rosaceae_ 218
g. Stipules absent.
_Saxifragaceae_ 196
c. Ovary one, the styles and stigmas
one to several.
d. Ovary with one cell and one
placenta.
e. Corolla forming standard,
wings and keel; filaments
mostly united. _Fabaceae_ 242
e. Corolla not of standard, wings
and keel; filaments mostly
not united.
f. Stamens ten or five; fruit
smooth, slender. _Cassiaceae_ 264
f. Stamens three or four;
fruit spiny, globose.
_Krameriaceae_ 268
d. Ovary with one or more cells
and styles, and two or more
placentae and stigmas.
e. Ovary one-celled.
f. Corolla irregular; petals
and sepals five. _Violaceae_ 296
f. Corolla regular or nearly so.
g. Ovules attached at the
center or bottom of the
ovary. _Caryophyllaceae_ 112
g. Ovules attached on two
placentae.
h. Stamens equal; pod
on a stalk.
_Capparidaceae_ 186
h. Stamens unequal;
pod without a stalk.
_Cruciferae_ 174
e. Ovary more than one-celled.
f. Ovary three-celled; trees
with palmate leaves.
_Hippocastanaceae_ 280
f. Ovary more than three-celled.
g. Cells of ovary as many
as the sepals.
h. Anthers opening by
terminal pores; dwarf
evergreen shrubby
plants. _Pyrolaceae_ 354
h. Anthers opening by
longitudinal slits.
i. Ovules and seeds
one or two in each
cell.
j. Herbs with lobed
or cut leaves.
_Geraniaceae_ 274
j. Evergreen
shrubs with varnished
leaves.
_Zygophyllaceae_ 268
i. Ovules and seeds
several in each cell;
leaflets three.
_Oxalidaceae_ 272
g. Cells of ovary twice as
many as the sepals.
_Linaceae_ 270
=D. Ovary inferior or more or less so.=
a. Stamens more than ten in number.
b. Plant spiny; leaves absent or soon
deciduous. _Cactaceae_ 304
b. Plant not spiny; leaves persisting for
the season.
c. Leaves three-sided, fleshy. _Aizoaceae_ 108
c. Leaves neither three-sided nor
fleshy.
d. Herbs; leaves rough-hairy.
_Loasaceae_ 300
d. Shrubs or trees.
e. Leaves opposite; stipules
none. _Hydrangeaceae_ 206
e. Leaves alternate; stipules present.
_Pomaceae_ 214
a. Stamens ten or fewer in number.
b. Ovules and seeds more than one in
each cell.
c. Ovary one-celled; fruit a berry.
_Grossulariaceae_ 210
c. Ovary with two or more cells.
d. Stamens four or eight.
e. Shrubs; filaments two-forked
at the apex. _Hydrangeaceae_ 206
e. Herbs; filaments not two-forked
at the apex. _Onagraceae_ 312
d. Stamens five or ten; styles two or
three. _Saxifragaceae_ 196
b. Ovules and seeds only one in each cell.
c. Stamens mostly ten; ovary partly
inferior. _Hydrangeaceae_ 206
c. Stamens less than ten; ovary wholly
inferior.
d. Stamens five; fruit dry.
_Umbelliferae_ 332
d. Stamens four; fruit fleshy.
_Cornaceae_ 338
=C. Corolla with petals more or less united.=
=E. Ovary superior.=
a. Stamens more than five in number.
b. Ovary one-celled.
c. Placenta one.
d. Corolla very irregular; stamens
not protruding from the corolla.
_Fabaceae_ 242
d. Corolla nearly regular; stamens
protruding. _Mimosaceae_ 266
c. Placentae two; corolla irregular.
_Fumariaceae_ 168
b. Ovary two to several-celled.
c. Ovary two-celled; corolla irregular.
_Polygalaceae_ 278
c. Ovary three or more-celled; corolla
regular or nearly so.
d. Stamens not attached to the
corolla.
e. Style one; leaves simple.
_Ericaceae_ 340
e. Styles more than one.
f. Styles three; erect spiny
shrub. _Fouquieriaceae_ 294
f. Styles five; low herbs.
_Oxalidaceae_ 272
d. Stamens attached to the corolla,
plants without green foliage.
_Monotropaceae_ 356
a. Stamens five or fewer in number.
b. Corolla regular.
c. Stamens free from the corolla.
_Ericaceae_ 340
c. Stamens attached to the corolla.
d. Pistil one.
e. Stamens of the same number
as the corolla lobes and opposite
them. _Primulaceae_ 362
e. Stamens alternate with the
corolla lobes or fewer.
f. Ovary one- or two-celled.
g. Styles two or occasionally
one.
h. Capsule usually
many-seeded; sepals
united.
_Hydrophyllaceae_ 402
h. Capsule few-seeded;
sepals separate.
_Convolvulaceae_ 380
g. Styles one or none.
h. leaves opposite.
i. Trees with pinnate
leaves. _Oleaceae_ 366
i. Herbs with simple
smooth-edged
leaves.
_Gentianaceae_ 368
h. Leaves alternate.
i. Ovary one-celled;
leaves with three
leaflets.
_Menyanthaceae_ 380
i. Ovary two-celled;
leaves various.
_Solanaceae_ 458
f. Ovary three- or four-celled.
g. Style one; ovary three-celled.
_Polemoniaceae_ 384
g. Styles two; ovary four-celled.
_Boraginaceae_ 422
d. Pistils two.
e. Stamens and stigmas united;
flowers with hood-like appendages.
_Asclepiadaceae_ 374
e. Stamens and stigmas not
united; flowers without
hood-like appendages.
_Apocynaceae_ 378
b. Corolla more or less irregular.
c. Fruit a many-seeded capsule.
d. Ovary two-celled. _Scrophulariaceae_ 466
d. Ovary one-celled; plants without
green foliage. _Orobanchaceae_ 504
c. Fruit of two or four seed-like nutlets.
d. Ovary four-lobed; plants mostly
aromatic. _Labiatae_ 434
d. Ovary not lobed; plants rarely
aromatic. _Verbenaceae_ 434
=E. Ovary inferior.=
a. Stamens eight or ten; evergreen shrubs.
_Ericaceae_ 340
a. Stamens five or fewer in number.
b. Plants tendril-bearing. _Cucurbitaceae_ 518
b. Plants not tendril-bearing.
c. Stamens free, not united.
d. Leaves alternate; stamens free
from the corolla. _Campanulaceae_ 520
d. Leaves opposite or whorled; stamens
inserted on the corolla.
e. Stamens one to three.
_Valerianaceae_ 508
e. Stamens four to five.
f. Leaves opposite, never in
whorls nor with stipules.
_Caprifoliaceae_ 512
f. Leaves opposite and with
stipules, or in whorls and
without stipules. _Rubiaceae_ 506
c. Stamens united by their anthers.
d. Corollas all strap-shaped and perfect;
juice milky. _Cichoriaceae_ 570
d. Marginal corollas strap-shaped,
never perfect; disk corollas perfect;
juice not milky. _Compositae_ 522