Diversity And Classification of Flowering Plants:

Eudicots: Asterids

Michael G. Simpson

Asterids

• Very large, diverse group

• 10 orders, many families

• Putative apomorphies:– iridoid compounds– sympetalous corolla– ovules: unitegmic (one integument),

tenuinucellate (megasporangium 1-cell thick)

Ovules unitegmic, tenuinucellate

Apocynaceae, s.l. - Dogbane/Milkweed family (Greek for "away from dog," in reference to past use of some taxa as a dog poison). 411 genera / 4,650 species.

The Apocynaceae, s.l. are distinctive in being lianas, trees, shrubs, or herbs with a 5-merous perianth/androecium, the gynoecium usually with 2 carpels, the ovaries distinct in some taxa with styles connate (in Asclepiadoids androecium adnate to single stigma forming a gynostegium and pollen fused to form pollinia, each half derived from an adjacent anther), the fruits variable, but a schizocarp of follicles in the Asclepiadoids.

K (5) C (5) A 5 or (5) G (2) [(-8)], superior, rarely half-inferior.

retinaculum

pollinium

2 ovaries, 2 styles, 1 stigma

Rubiaceae — Coffee family (after rubia, name used by Pliny for madder)

630 genera / 10,200 species.The Rubiaceae are distinctive in being trees, shrubs, lianas, or

herbs with simple, entire, usually decussate leaves and connate stipules, the stipules often with mucilage-secreting colleters, the inflorescence usually a cyme, flowers usually bisexual, the perianth dichlamydeous, perianth and androecium often 4 –5-merous (calyx absent in some), the ovary usually inferior (rarely superior), often with an apical nectariferous disk, ovules with a funicular obturator, the fruit a berry, capsule, drupe, or schizocarp.

K (4-5) [0] C (4-5) [(3,8-10)] A 4-5 [3,8-10] G (2) [(3-5+)], usually inferior, rarely superior.

Rubiaceae — Coffee family (after rubia, name used by Pliny for madder)

630 genera / 10,200 species.

The Rubiaceae have a mostly worldwide distribution,

more concentrated in tropical regions. Economic

importance includes Cinchona, the source of quinine

used to treat malaria, Coffea arabica and other

species, the source of coffee, Pausinystalia johimbe,

the source of the sexual stimulant yohimbine, some

timber trees, fruiting plants, dye plants (such as Rubia,

madder), and ornamental cultivars (e.g., Pentas,

among others).

Acanthaceae — Acanthus family (from Acanthus, prickly-one).229 genera / 3450 species.

The Acanthaceae are distinctive in having simple,

opposite leaves with zygomorphic, bracteate,

usually bilabiate flowers, the fruit an explosively

dehiscent, loculicidal capsule with distinctive

funicular retinacula ( jaculators) that function in

seed dispersal, the funicular retinacula a presumed

apomorphy of the family.

K (5) [(4,6)] C (4-5) A 2,4,or 5 G (2), superior.

Acanthaceae — Acanthus family (from Acanthus, prickly-one).229 genera / 3450 species.

Members of the Acanthaceae are distributed from the

tropics to temperate regions. Economic importance

includes several cultivated ornamentals, such as

Acanthus mollis, Aphelandra, and Justicia [including

Beloperone]

Lamiaceae (=Labiatae) - Mint family (Lamium, gullet, after the shape of the corolla tube or old Latin name

used by Pliny). 251 genera / 6,700 species.

The Lamiaceae are distinctive in being herbs or shrubs, often

aromatic with ethereal oils, with usually 4-sided stems, opposite [or whorled] leaves, a verticillaster or thyrse inflorescence [flowers solitary and axillary in some], and zygomorphic [rarely actinomorphic], usually bilabiate flowers having a superior, deeply 4-lobed ovary (by formation of "false septa") and gynobasic style, the fruit a schizocarp of usually 4 nutlets.

K (5) C (5) [(4)] A 4 or 2 [+2 staminodes] G (2), superior, hypanthium absent.

Economic importance includes medicinals, herbs (e.g., Mentha,

mint; Ocimum, basal; Rosmarinus, rosemary; Salvia, sage;

Thymus, thyme), fragrance plants (e.g., Lavandula, lavender;

Pogostemon, patchouli), and a number or cultivated

ornamentals.

Leaves opposite; stems 4-sided

Inflorescence a thyrse or verticillaster (usu.)

Flowers zygomorphic; corolla sympetalous, bilabiate

carpels 2; style gynobasic

Fruit a schizocarp of nutlets

Ocimum basilicum BASIL

Rosmarinus officinalis ROSEMARY

Salvia apiana WHITE SAGE

enantiostylous flowers

Pogogyne abramsii MESA MINTFed/Cal. endangered species

Salvia columbariae CHIA

Solanaceae - Nightshade family (Latin for sleeping or comforter, after narcotic properties of

some). 94 genera / 2,950 species.

The Solanaceae are distinctive in being herbs, shrubs, trees, or lianas with internal phloem, spiral leaves, a usually actinomorphic, 5-merous perianth and androecium (corolla plicate in bud), a usually bicarpellate, syncarpous gynoecium, and usually numerous ovules per carpel, the fruit a berry, drupe, or capsule.

K (5) C (5) [(4),(6)] A 5 [4 or 2+2 staminodes] G (2) [(3-5)], superior, hypanthium absent.

Members of the family have mostly worldwide distributions, concentrated in South America.

Economic importance includes many edible plants, such as Capsicum (peppers), Lycopersicon esculentum (tomato), Physalis philadelphica (tomatillo), Solanum tuberosum (potato), Nicotiana tabacum (tobacco); alkaloids from various taxa have medicinal properties (e.g., atropine from Atropa belladona), hallucinogenic properties (e.g., Datura, Jimson weed), or are deadly poisons (e.g., Datura, Solanum spp.) or known carcinogens (e.g., Nicotiana tabacum); some used as ornamental cultivars, others are noxious weeds.

Flowers actinomorphic,

plicate (in bud)

Flowers actinomorphic,

plicate (in bud)

Fruit a berry or capsule

Physalis ixocarpa Tomatillo

Asteraceae (Compositae)

Characteristics:

Vegetatively variable.

Inflorescence a head (capitulum): (usu.) many flowers arising from a compound receptacle, subtended by inflorescence bracts: involucral bracts or phyllaries, collectively termed the involucre.

Calyx modified as pappus.

Stamens syngenesious.

K pappus C 5 A (5) G(2), inferior, 1 basal ovule

Fruit an achene.

Asteraceae (=Compositae) - Sunflower family

(after Aster, meaning star). 1,528 genera / 22,750 species.

The Asteraceae are distinctive in being herbs, shrubs, vines, or trees, the inflorescence a head (capitulum) subtended by an involucre of phyllaries, flowers either bilabiate, disk, or ray/ligulate, (heads of many taxa a mixture of central disk flowers and peripheral ray flowers), with the calyx, termed a pappus, modified as scales, awns, or capillary bristles (or absent), the androecium syngenesious, and with an inferior ovary with a single, basal ovule, the fruit a multiple of achenes.

Asteraceae (=Compositae) - Sunflower family

(after Aster, meaning star). 1,528 genera / 22,750 species.

Economic importance includes some food plants (e.g., Cynara scolymus, artichoke, and Helianthus annuus, sunflower), a number of ornamental cultivars, and various species used locally or industrially; the prickly fruits of Arctium lappa (burdock) are purported to have been the model for invention of velcro.

Argyroxiphium sandwicense, SilverswordMaui

Argyroxiphium sandwicense, SilverswordMaui

Asteraceae (=Compositae) - Sunflower family

(after Aster, meaning star). 1,528 genera / 22,750 species.

K 0-∞ (pappus)

C (5) [(4)] or (3) in some ray flowers

A (5) [(4)]

G (2), inferior, hypanthium absent.

Asteraceae: floral variationThree types of flowers:

1) Bilabiate: zygomorphic (bilateral) with 2 lips2) Ray (ligulate): zygomorphic (bilateral) with 1

lobe3) Disk: actinomorphic (radial), usu. 5-lobed

Five types of heads:

1) discoid, with only disk flowers;

2) disciform, with central disk flowers and marginal, eligulate female flowers;

3) radiate, with central (bisexual or male) disk flowers and peripheral (female or sterile) ray flowers;

4) ligulate, with all ray flowers (typically with 5-toothed corolla apices);

5) bilabiate, with all bilabiate flowers.

Bilabiate flower

Acourtia microcephala Trixis californica

posterior lip anterior lip

ligulate / raydisk

syngenesious

anthers connate

Ray flowers (heads ligulate = all rays)

Rafinesquia neomexicana Malacothrix californica

ligulate corolla

Disk flower: heads discoid

Palafoxia arida Psathyrotes ramosissima

disk corolla

Chaenactis gabriuscula

Disk flowers: heads disciform(2 types of disk fls.,

same or different heads)

male heads

Ambrosia chamissonis

female heads

Xylorhiza orcuttii Encelia farinosa

Heads radiate: inner disk & outer ray fls.

ray flowers disk flowers

Encelia californica

ovary

Some heads are "chaffy"

chaff : bracts subtending flowers

disk flower

Involucre morphology

one whorl two whorls many whorls

Senecio vulgaris Coreopsis maritima Encelia californica

Circium vulgare Silybum marianum

Phyllaries spiny

Involucre morphology

Phyllaries spiny & squarrose

Pappus: modified calyx

capillary bristles: barbellate

capillary bristles: plumose

beak

capillary bristles, borne atop "beak"

Pappus: modified calyx