a) Flowers arranged in a dense head surrounded by numerous imbricate bracts; stamens 4, opposite the calyx (or perianth) lobes, the latter valvate, one splitting away from the other three; leaves alternate, without stipules.
aa) Flowers variously arranged but not in heads with an involucre of bracts; remainder of above characters not associated:
b) Ovary composed of 1 carpel (i.e., with 1 placenta):
c) Stamens numerous, free or very slightly connate at the base; pod stipitate.
Papilionaceæ
(Cordyla)
cc) Stamens 10 or fewer:
d) Flowers hermaphrodite, not very small; leaves usually compound.
dd) Flowers unisexual or polygamous, usually very small; leaves usually simple:
e) Ovule pendulous; anthers erect in bud; flowers solitary or cymose or fasciculate.
ee) Ovule pendulous or erect; anthers erect or inflexed in bud; flowers often on or within an enlarged and often fleshy receptacle or in catkins or heads.
bb) Ovary composed of more than 1 carpel; at least with 2 or more placentas:
c) Ovary and fruit stipitate; seeds usually without endosperm and often with a curved embryo; sepals usually valvate.
cc) Ovary sessile:
d) Inflorescence a catkin; flowers dioecious; seeds pilose with a basal tuft of hairs, without endosperm.
dd) Inflorescence not a catkin but sometimes a slender pendulous spike or raceme; flowers usually hermaphrodite; seeds with endosperm.
e) Flowers hypogynous; no staminodes between the stamens; filaments free.
ee) Flowers perigynous; staminodes often present and alternating with the fertile stamens; filaments free or connate.
GROUP 7. One carpel or more than one united carpels; ovules on the walls of the ovary; ovary inferior; petals present, free from each other.
a) Flowers hermaphrodite; anthers straight or nearly so:
b) Anthers opening by pores; leaves mostly opposite with parallel main nerves; stamens definite, often double the number of the petals.
bb) Anthers not opening by pores:
c) Fleshy herbs or shrubs with reduced leaves and often epiphytic; stamens numerous; seeds without endosperm.
cc) Tree or shrubs with well-developed green leaves; seeds with endosperm; stamens sometimes opposite the petals.
aa) Flowers unisexual; stamens few, with twisted or conduplicate anthers; usually slender twiners with tendrils; leaves often scabrid.
GROUP 8. One carpel or more than one united carpels; ovules on the walls of the ovary; ovary inferior; petals present, more or less united.
Flowers unisexual; leaves alternate without longitudinally parallel nerves; tendrils often present; stamens mostly 3; anthers often twisted or conduplicate.
Flowers hermaphrodite; leaves opposite or verticillate often with longitudinally parallel nerves, without stipules; anthers mostly opening by terminal pores.
Flowers hermaphrodite, very rarely unisexual; leaves opposite or alternate, often stipulate; anthers not opening by pores, sometimes connivent at the apex; ovules numerous on the walls; petals united into a long tube; stipules persistent, inter- or intra-petiolar.
Rubiaceæ
(Gardenia)
GROUP 9. One carpel or more than one united carpels; ovules on the walls of the ovary; ovary inferior; petals absent; leaves exstipulate; calyx unilateral or 3 lobed and often coloured.
GROUP 10. One carpel or more than one united carpels; ovules attached to the central axis or to the base or apex of the ovary cell; ovary superior; petals present, free from each other.
a) Perfect stamens the same number as the petals and opposite to them; leaves alternate or rarely opposite or all radical:
b) Leaves not gland-dotted; petals and stamens more or less hypogynous or subperigynous; disk usually conspicuous:
c) Calyx lobes or sepals imbricate, usually 2; stipules often scarious or setose; ovary 1-celled, with basal placenta.
cc) Calyx lobes valvate or open in bud:
d) Disk absent from the flowers:
e) Trees and shrubs; ovules usually 2 or more inserted on the inner angle of the cells; hairs on the leaves often stellate.
ee) Herbs mostly with rosettes of leaves; flowers in corymbs; calyx tube scarious, ribbed; ovule 1, pendulous on a basal funicle.
dd) Disk present, perigynous; leaves mostly stipulate; ovary 2-4-celled; ovules erect; seeds mostly with copious endosperm and large straight embryo.
ddd) Disk present; leaves exstipulate:
e) Ovules erect; ovary 1-3-celled; calyx conspicuous.
ee) Ovules pendulous; ovary 1-celled; calyx minute.
bb) Leaves pellucid-punctate:
c) Leaves simple, without stipules; ovules numerous on a free central placenta; no tendrils.
cc) Leaves mostly compound, usually stipulate; inflorescence leaf-opposed; ovules 1-2 in each cell, inserted on the inner angle; tendrils often present.
aa) Perfect stamens the same number as the petals and alternate with them or more numerous, very rarely fewer:
b) Style basal; stipules mostly persistent; leaves simple; stamens numerous; stomata of the leaves usually with special subsidiary cells.
bb) Style or styles terminal or subterminal, sometimes gynobasic:
c) Flowers markedly zygomorphic (irregular); lower sepal more or less elongated into a spur; sepals usually 3; anthers connivent around the ovary, opening lengthwise; seeds without endosperm.
cc) Flowers actinomorphic or very slightly zygomorphic:
d) Stamens united into more than one separate bundle (phalanges) often opposite the petals; leaves usually opposite, often gland-dotted or with resinous lines:
e) Leaves opposite, exstipulate:
f) Herbs or shrubs; styles free from the base or nearly so; flowers hermaphrodite; calyx imbricate.
ff) Trees or shrubs; styles mostly more or less united or stigma one and sessile or sub-sessile; flowers mostly unisexual; calyx imbricate.
ee) Leaves alternate, stipulate; trees, shrubs or herbs; calyx valvate; hairs usually stellate:
f) Stamens with some of the filaments sterile; fruits not hooked.
ff) Stamens all fertile; fruits covered with hooks.
dd) Stamens free (at least not united into several bundles) or sometimes more or less united at the base or into one bundle (monadelphous):
e) Leaves opposite or verticillate or rarely fasciculate, never all radical:
f) Leaves compound, rarely unifoliolate and then with a distinctly tumid petiole, sometimes sessile:
g) Leaves gland-dotted; disk usually present between the stamens and ovary; ovary often deeply lobed; cells 2-ovuled; pendulous; stipules rarely present.
gg) Leaves not gland-dotted, sometimes fleshy; ovules pendulous from the central axis, 2 or more in each cell; disk often fleshy, rarely absent; stipules persistent and often paired; shrubs or herbs; leaves mostly 2-foliolate or pinnate; filaments often with a scale or gland attached to the base.
ff) Leaves simple but sometimes deeply and variously divided:
g) Stamens more than twice as many as the petals; calyx valvate:
h) Flowers hermaphrodite; anthers not inflexed in bud:
i) Petals and stamens hypogynous; hairs often stellate; stipules in pairs.
ii) Petals and stamens perigynous; hairs not stellate; stipules interpetiolar.
hh) Flowers hermaphrodite; anthers inflexed in bud; petals and stamens perigynous.
hhh) Flowers unisexual; anthers inflexed in bud; hairs stellate or lepidote.
gg) Stamens not more than twice as many as the petals:
h) Trees, shrubs or woody climbers:
i) Leaves stipulate, sometimes stipules rudimentary or of hairs:
j) Disk absent or inconspicuous or of separate glands; calyx often glandular:
k) Calyx mostly with a pair of glands outside; trees, shrubs or climbers; stamens mostly 10.
Malpighiaceæ
kk) Calyx not glandular; anther-cells back to back; trees or shrubs; petals 4; stamens 4.
jj) Disk present, conspicuous; calyx not glandular:
k) Flowers hermaphrodite:
l) Stamens inserted on or below the margin of the disk; filaments subulate:
m) Stamens 3-5; sepals imbricate.
mm) Stamens 8-10; sepals valvate.
ll) Stamens usually 3, inserted on the disk; filaments flattened or connivent, often adnate to the ovary; sepals imbricate.
kk) Flowers unisexual; ovules pendulous from the apex of the cell; seeds often carunculate.
ii) Leaves exstipulate or stipules gland-like:
j) Anthers opening at the apex by a pore, often appendaged at the base; stamens as many or twice as many as the petals; leaves often with 3-9 longitudinally parallel nerves.
jj) Anthers opening by slits lengthwise; leaves usually with pinnate nerves:
k) Ovules numerous in each cell; anthers inflexed in bud; calyx more or less tubular, with valvate lobes, often with accessory lobes.
kk) Ovules few in each cell:
Malpighiaceæ
l) Ovules pendulous from the apex of the cells; calyx fairly long and tubular, more or less petaloid; petals usually very small.
ll) Ovules erect or ascending from the base of the cells; calyx imbricate:
m) Filaments subulate or filiform; stamens usually 5.
mm) Filaments flattened; stamens usually 3.
hh) Herbs, sometimes slightly woody at the base:
i) Leaves stipulate; stipules paired; styles free from the base; ovules numerous, axile.
ii) Leaves exstipulate:
j) Leaves with 3 or more longitudinally parallel nerves; anthers usually appendaged and opening by a terminal pore.
jj) Leaves not as above; anthers opening by longitudinal slits; stamens perigynous; anthers inflexed in bud.
ee) Leaves alternate or all radical:
f) Stamens more than twice the number of the sepals or petals:
g) Sepals valvate or open in bud:
h) Anthers 2-celled:
i) Stamens free or slightly united only at the base:
j) Calyx closed in bud:
k) Flowers hermaphrodite; leaves simple; wood not resinous.
kk) Flowers unisexual; leaves entire or 3-lobed; petiole with 2 glands at the apex.
kkk) Flowers usually polygamous; leaves mostly compound; petiole not glandular at the apex; wood resinous.
jj) Calyx open in bud; leaves simple; stamens up to 20, free or nearly so.
ii) Stamens more or less united into a tube or into bundles, hypogynous; indumentum usually stellate.
hh) Anthers 1-celled, stamens more or less monadelphous; calyx with or without an epicalyx:
i) Trees or rarely shrubs; leaves digitately compound; carpels not or very rarely splitting away from the central axis in fruit.
ii) Mostly herbs; leaves simple; carpels often splitting away from the central axis or becoming free in fruit.
gg) Sepals imbricate or rarely completely connate or calyptrate:
h) Petals and stamens perigynous; leaves stipulate:
i) Seeds with endosperm and a curved embryo; mostly herbs; sepals 2.
ii) Seeds without endosperm; sepals more than 2.
hh) Petals and stamens more or less hypogynous or flowers unisexual; disk often present:
i) Trees, shrubs or woody climbers:
j) Leaves compound, pinnate or rarely unifoliolate and then with a tumid petiole:
k) Ovule ascending:
l) Leaves gland-dotted; style or styles central.
ll) Leaves rarely gland-dotted; styles or stigmas often separated:
m) Wood with resin ducts and leaves scented; style or stigma often eccentric.
mm) Wood not resinous; leaves not or rarely scented; style or stigma central.
kk) Ovule or ovules pendulous; wood without resin ducts, bark bitter; leaves usually not gland-dotted.
jj) Leaves simple:
k) Flowers unisexual; disk present.
kk) Flowers hermaphrodite:
l) Torus enlarged after flowering; ovary mostly deeply lobed, the carpels becoming separated in fruit; anthers often opening by pores.
ll) Torus not enlarged; calyx enlarged and wing-like in fruit:
m) Flowers mostly rather small and not showy; petals much contorted; ovary 2- or more-celled; leaves with comparatively few lateral nerves.
mm) Flowers showy; ovary 1-celled with a basal placenta; leaves long, with very numerous parallel lateral nerves.
ii) Herbs; sepals 2; leaves fleshy, exstipulate; ovary 1-celled with numerous ovules; seeds strophiolate.
ff) Stamens definite in number in relation to the sepals or petals, often the same number or twice as many or fewer:
g) Leaves compound, rarely unifoliolate and then with a distinctly tumid petiole:
h) Stamens united into a tube; leaves pinnate or rarely unifoliolate, exstipulate; flowers actinomorphic; seeds often winged.
hh) Stamens free or united only at the base:
i) Leaves stipulate:
j) Herbaceous or slightly woody; leaves digitately or pinnately compound.
jj) Trees, shrubs or often climbers; leaves compound; stipules lateral; seeds without endosperm.
ii) Leaves exstipulate:
j) Leaves gland-dotted:
jj) Leaves not gland-dotted:
k) Ovules pendulous:
l) Leaflets 2; shrubs or trees with axillary or supra-axillary spines.
ll) Leaflets more than 2:
m) Ovary of more than 1 carpel, 2 or more celled.
mm) Ovary usually of 1 carpel.
kk) Ovules ascending or horizontal:
l) Ovules 2 in each cell, collateral; style simple; ovary of 1 carpel.
ll) Ovules 1 or more in each cell, erect or ascending; style simple or divided; ovary of more than 1 carpel.
gg) Leaves simple:
h) Anthers opening by apical pores; ovary deeply lobed, torus enlarging in fruit and the carpels often becoming separate; ovules 1-2 in each cell.
hh) Anthers opening by slits lengthwise:
i) Shrubs or trees:
j) Leaves stipulate:
k) Flowers unisexual:
l) Petals entire:
m) Stipules conspicuous, persistent.
mm) Stipules very inconspicuous, caducous.
ll) Petals bilobed; stamens 5; disk composed of hypogynous glands opposite the petals.
kk) Flowers hermaphrodite:
l) Stipules axillary, convolute in bud, often very large; ovary entire, 2-celled; petals entire; ovule inserted in the middle of the placenta.
Simarubaceæ
(Irvingia)
ll) Stipules not axillary:
m) Petals entire or emarginate; ovules erect; disk entire or lobed.
mm) Petals often deeply lobed; ovules pendulous; disk of separate glands opposite the petals.
jj) Leaves exstipulate:
k) Stamens united into a tube; sepals not glandular; ovary 2- or more-celled.
kk) Stamens free or connate only at the base:
l) Stamens hypogynous or very slightly perigynous:
m) Ovary 1-celled:
n) Leaves fairly large; flowers in panicles, not supported on the enlarged torus.
nn) Leaves very small and crowded; flowers in slender spikes or racemes.
mm) Ovary 2- or more-celled; disk present; petals mostly valvate; ovary 3-5-celled.
ll) Stamens distinctly perigynous; calyx tubular and often petaloid; petals mostly very small and scale-like.
ii) Herbs:
j) Flowers hermaphrodite; disk usually absent:
k) Sepals valvate; bark fibrous; leaves often with thread-like tails at the base.
kk) Sepals imbricate; leaves not tailed at the base; ovary long-beaked.
kkk) Sepals imbricate; leaves not tailed; ovary not beaked.
l) Petals not contorted:
ll) Petals contorted:
jj) Flowers unisexual; disk present or obscure.
GROUP 11. One carpel or more than one united carpels; ovules attached to the central axis or to the base or apex of the ovary cell; ovary superior; petals present, more or less united.
a) Stamens the same number as and opposite to the corolla lobes:
b) Ovules solitary in the whole ovary or in each cell of the ovary; style often lobed:
c) Trees or shrubs, often with hard wood:
d) Petals imbricate; hairs often stellate or medifixed; staminodes often present, sometimes petaloid.
dd) Petals valvate; hairs usually simple; usually no staminodes:
e) Inflorescence not leaf-opposed; leaves simple, without tendrils.
ee) Inflorescence leaf-opposed; leaves often compound; mostly climbers with tendrils.
cc) Herbs or climbers:
d) Corolla lobes valvate; tendrils often present; inflorescence usually cymose-paniculate, leaf-opposed; leaves usually with the stipules adnate to the petiole; petals united at the base.
dd) Corolla lobes imbricate; no tendrils; inflorescence more or less corymbose; petals united high up.
bb) Ovules 2 or more in each cell; style undivided; placentas basal:
c) Trees or shrubs often with gland-dotted simple leaves; leaves exstipulate.
cc) Herbs or climbers usually with compound stipulate leaves and leaf-opposed inflorescence.
ccc) Herbs with opposite simple leaves and solitary or axillary scarlet, blue or rose flowers; leaves not gland-dotted, exstipulate.
aa) Stamens the same number as the corolla-lobes and alternate with them, or more numerous or fewer:
b) Stamens more than twice as many as the corolla lobes; flowers unisexual; corolla lobes about 5; leaves stipulate.
bb) Stamens as many as or up to twice as many as the corolla lobes or fewer:
c) Stamens as many as or more numerous than the corolla lobes:
d) Flowers zygomorphic (irregular):
e) Petals united only at the base; seeds often pilose; ovules pendulous.
ee) Petals united high up into a tube:
f) Ovules numerous in each cell; herbs; corolla lobes 5.
ff) Ovules solitary in each complete or incomplete cell; habit various; corolla lobes 4.
dd) Flowers actinomorphic (regular):
e) Leaves opposite or verticillate, mostly exstipulate:
f) Anthers opening by apical pores or pore-like slits:
g) Leaves in whorls; woody shrubs or undershrubs with usually very small leaves; stamens hypogynous.
gg) Leaves paired; herbs; stamens epipetalous.
ff) Anthers opening by longitudinal slits:
g) Style single with often a large more or less capitate stigma:
h) Corona present in the flowers; mostly herbs or weak twiners, often with milky juice.
hh) Corona absent:
i) Leaves exstipulate:
j) Trees, shrubs or climbers often with milky juice; corolla lobes contorted-imbricate or rarely valvate.
jj) Herbs; corolla lobes imbricate; disk present.
jjj) Herbs with spicate flowers and radical leaves; corolla lobes imbricate; no disk.
ii) Leaves stipulate or sheathing at the base.
gg) Styles with more than 1 separate stigma:
h) Stamens double the number of the corolla lobes; flowers dioecious; endosperm copious, hard.
hh) Stamens the same number as the corolla lobes:
i) Rudimentary stipules often present; stamens and corolla lobes 4.
ii) Stipules absent:
j) Style gynobasic:
jj) Style terminal:
k) Trees or shrubs:
l) Ovules numerous in each cell or, if solitary, then corolla lobes valvate.
ll) Ovules 1-2 in each cell; corolla lobes imbricate.
kk) Herbs or herbaceous climbers:
l) Ovary imperfectly celled by the intrusive placentas.
ll) Ovary perfectly 2-celled with axile placentas; style simple.
ee) Leaves alternate or all radical or reduced to scales:
f) Leafless parasites destitute of chlorophyll; ovary 2-celled; ovules 2 in each cell.
ff) Not parasitic or rarely so and then leafy:
g) Leaves densely covered with viscid gland-tipped tentacles, mostly all radical; more or less stemless herbs.
gg) Leaves without tentacles:
h) Leaves stipulate:
i) Flowers unisexual; petals not bifid.
ii) Flowers hermaphrodite; petals bifid.
hh) Leaves without stipules:
i) Stamens hypogynous or perigynous, free from the corolla or slightly adnate to its base:
j) Anthers opening by terminal pores, often with appendages; woody plants.
jj) Anthers opening by longitudinal slits:
k) Stamens 4-6:
l) Leaves gland-dotted; petals connivent by their claws; disk usually conspicuous.
ll) Leaves not gland-dotted.
m) Petals only slightly united at the base:
n) Leaves pinnate or 1-3-foliolate.
nn) Leaves simple:
o) Stamens opposite the petals.
oo) Stamens alternate with the petals.
mm) Petals united high up, sometimes free at the base:
n) Trees or shrubs.
nn) Herbs.
kk) Stamens more than 6:
l) Corolla tube fairly long; no disk; leaves not very small.
ll) Corolla tube very short; disk present; leaves very small.
ii) Stamens inserted on or adnate to the corolla tube:
j) Style gynobasic:
k) Style 1; fruit composed of pyrenes or nutlets; corolla imbricate or contorted.
kk) Styles 2; fruit a capsule; corolla plicate.
jj) Style not gynobasic, terminal:
k) Corolla valvate or plaited in bud (in the latter case the limb may be somewhat twisted but not truly imbricate):
l) Ovules 1-4 in each ovary cell; stamens inserted towards the base of the corolla tube.
ll) Ovules numerous (rarely 3-6) in each ovary cell.
kk) Corolla imbricate:
l) Herbs with radical leaves and flowers in slender spikes.
ll) Herbs, trees or shrubs; flowers not in slender spikes:
m) Ovules 1 in each cell; trees and shrubs.
mm) Ovules numerous in each cell; herbs or small shrubs.
cc) Stamens fewer than the corolla lobes; leaves mostly opposite:
d) Flowers actinomorphic:
e) Stamen 1; climbers or shrubs; seeds winged; one calyx lobe much larger than the others and petaloid.
ee) Stamens more than 1:
f) Stamens 6-8 opposite the inner lobes of the corolla; ovules solitary in each cell; trees or shrubs.
ff) Stamens alternate with the corolla lobes:
g) Peduncle of the inflorescence adnate to the petiole; corolla lobes or some of them 2-cleft.
gg) Peduncle not adnate to the petiole; corolla lobes not cleft or only slightly so:
h) Ovules few (1-4) in each cell of the ovary:
i) Disk none; stamens 2; shrubs, trees or climbers; leaves simple or pinnate.
ii) Disk present; stamens usually 4; shrubs or trees; leaves simple or digitate.
hh) Ovules numerous:
i) Corolla lobes minute, valvate, alternating with entire or 2-lobed appendages.
ii) Corolla lobes imbricate, without appendages.
dd) Flowers zygomorphic:
e) Aquatic herbs with bladder-like leaves; stamens 2; anthers 1-celled; sepals 2; ovules on a free basal placenta.
ee) Characters not as above:
f) Ovary not deeply lobed; style not gynobasic:
g) Ovules numerous in the whole ovary or in each cell of the ovary, or if 2 then superposed:
h) Leaves pinnately compound; ovules numerous; seeds often winged, without endosperm; shrubs or trees.
hh) Leaves simple; mostly herbaceous:
i) Ovules numerous; ovary 2-celled; seeds usually minute.
ii) Ovules 1 to many; ovary 2-4 celled; seeds not on hook-like funicles.
iii) Ovules few; ovary 2-celled; leaves rarely all radical; seeds on hook-like funicles.
gg) Ovule solitary in each cell of the ovary or if 2 then collateral; herbs, shrubs or trees.
ff) Ovary deeply 4-lobed; style gynobasic; leaves opposite or verticillate; flowers often in whorls; stems usually quadrangular.