Important North American Angiosperm plant families: grouped artificially for rapid identification

Overview

This is just a starting point. There are exceptions to the characteristics mentioned here and there are of course many more plant families. Abbreviations: lvs=leaves, flwrs = flowers. Regular (actninomorphic) flowers are radially symmetrical. Irregular= bilaterally symmetrical or other.

Monocot families

Conspicuous perianth

  • Amaryllidaceae: scapose umbel
  • Iridaceae: 3 stamens, inferior ovary
  • Liliaceae: Infl raceme or panicle, 3-parted stigma, 6 tepals
  • Asparagaceae (Agavodiae subfamily): stiff rosette basal lvs, Agave, Yucca, Dasylirion, Hesperaloe
  • Commelinaceae | Lvs involute, +/- succulent,swollen nodes

Inconspicuous perianth

  • Juncanceae: round solid stems (or rounded 3-sided), 2-ranked lvs, 6 tepals
  • Cyperaceae: 3-sided stems with edges, 3-ranked lvs, terminal inflorescence
  • Poaceae: 2-rank flowers

(eu)Dicot families

flower parts format (calyx, corolla, androecium). “inf” means more than double other floral parts.

Superior ovary

Petals separate, ovary superior flowers actinomorphic OR zygomorphic

  • Ranunculaceae: (3-x;0-x; inf.) dissected lvs; Delphinum, Aquilegia
  • Papaveraceae: (2-3;4-12;inf.) sepals caducous (easily shed), petals wrinkled
  • Brassicaceae: (4;4;2+4) 6 stamens with 4 long, 2 shorter, fruit usually a silique, herbs
  • Caryophylaceae: (5;5;5 or 10) opposite lvs & swollen nodes
  • Malvaceae: (3-5;5;inf.) stamens fused around style, stellate hairs, palmately lobed leaves
  • Rosaceae: (5;5;inf.) hypanthium (perigynous), stipules
  • Fabaceae (three major clades):
    • Papilionoideae (5;1+2+2;10) pea-like, banner outside of wings
    • Caesalpinioideae (5;5;10) not pea-like, banner inside of wings
    • Mimusoidaeae (5;5;inf.) stamens obvious. Prosopis, Mimosa, (and former Acacia now Senegalia and Vachellia).

Petals unitied, ovary superior and flowers regular (actinomorphic)

  • Convolvulaceae: (5;5;5 corolla convulate or twisted
  • Ericaceae: (4-5;5;5 or 10) united sepals, stamens not adnate to corolla, sometimes bell-shaped flwrs.
  • Polemoniaceae: (5;5;5) 3-parted stigma, corolla salverform
  • Hydrophylaceae: (5;5;5) Inflorescence a scorpoid cyme, 2 styles +/- free. Lvs often hairy.
  • Boraginaceae: (5;5;5) scorpoid (coiling) cyme, 4 nutlets, bristly
  • Solanaceae: (5;5;5) tubular or rotate corolla, stigma capitate
  • Gentianaceae: (4-5;4-5;4-5) 2 carpels, opposite glabrous sessile or subsessile lvs, stamens alternate with corolla lobes.

Petals united, ovary superior & flowers irregular (zygomorphic)

  • Lamiaceae (5;5;2 or 4) opposite lvs, square stem, aromatic, 4-nut, mostly herbaceous.
  • Verbenaceae (5;5;2 or 4) opposite lvs, square stem, flwrs weakly irregular. Aloysia, Lantana.
  • Former Scrophulariaceae, now Plantaginaceae (5;5;2or4) often opposite lvs, fruit a capsule.
  • Former Scrophulariaceae, now Phrymaceae (5;5;4 in 2 lengths). Stigmas with two lamellas. Often opposite lvs. Monkeyflowers.
  • Orobanchaceae (2-5;5;4). 5th stamen sterile if present. Mostly parasitic plants. Fruit a capsule.
  • Bignoniaceae (5,5,4 in 2 lengths) opposite often compound lvs. Tropical and subtropical trees, vines, and shrubs.

Inferior ovary

  • Onagraceae (4;4; 8 or 4). Petals separate but tubular hypanthium.
  • Cucurbitaceae (5;5; 5 sometimes fused to 1-3) Unisexual (imperfect) flowers. Petals united.
  • Rubiaceae (4-5;4-5;4-5) opposite lvs that are simple and entire or whorled leaves, interpetiolar stipules, tubular actinomorphic corolla.
  • Caprifoliaceae (4-5;4-5;5 or 4) Zygomorphic tubular flowers, opposite lvs, capitate stigma
  • Myrtaceae (4-5,4-5,inf.) glandular-punctate lvs.
  • Cornaceae (4-5;4-5;4-5 or 10) Leaf threads hold parts together when torn, small flowers. Cornus (dogwood)
  • Rosaceae (5;5;inf) Ovaries superior (with free hypanthium) to completely inferior.

No corolla, usually small flowers

  • Polygonaceae: 3-merous flowers (Polygonum with 5-merous), involucre. herbs and vines.
  • Nyctaginaceae: involucre, corolla-like calyx, opposite lvs, swollen nodes
  • Amaranthaceae (including former Chenopodiaceae): Scurfy; saline environments. Often reddish stems and lvs. Sepals surround fruit.

Milky juice

  • Euphorbiaceae: unisexual flowers or cyathium (some not milky)
  • Apocynaceae subfamily Asclepiadoideae (former Asclepidaceae): corona, opposite leaves
  • Apocynaceae subfamily Apocynoideae: twisted corolla, opposite or whorled lvs
  • Asteraceae: tribe Cichorieae: all ligulate (ray) flwrs
  • Moraceae: Maclura pomifera (Osage orange), Mulberry

Distinctive Inflorescence

  • Apiaceae: Inflorescence an umbel: often compound: and umbel of umbels.
  • Asteraceae: Head of flowers.

Succulents

  • Cactaceae: Many petals and stamens, inferior ovary, spines
  • Aizoaceae: many petals or if none then many showy stamens
  • Crassulaceae: (4-5;4-5;8-10) 4-5 separate carpels
  • Portulaceae: (2,4-6;4-inf) Often only slightly succulent

Shrubs

  • Anacardiaceae: (5;5;10) Evergreen or deciduous. staminal disk, often aromatic. Fruit a drupe. Rhus (sumacs)
  • Rhamnaceae: (4-5;4-5;4-5) Hypanthium. Many evergreen. Flowers small white or green Zyziphus (lotebush), Condalia, Colubrina, Ceanothus
  • Garryaceae Evergreen, opposite lvs, dioecious with catkins. One genus only: Garrya. Garry ovata

Trees with catkins of unisexual flowers

  • Fagaceae: monoecious, acorns + similar fruits, both evergreen and deciduous species. Quercus (oaks).
  • Salicaceae: dioecious, deciduous, most common in riparian (steamside) environments. Populus (cottonwood and aspen), Salix (willows)
  • Juglandaceae: monoecious, deciduous, pinnate compound lvs, often aromatic and glandular-dotted beneath. Juglans (walnut) and Carya (pecan)

Some other woody plant families

  • Betulaceae: Monoecious, deciduous, lvs simple and serrate
  • Ulmaceae: Most species monoecious (some with perfect flowers). Lvs alternate, simple and toothed/serrate, often arranged in plane. Flwrs reduced, mucilaginous sap.
  • Sapindaceae: Includes former Aceraceae. Trees or shrubs (a few vines). Usually pinnate compound lvs: Sapindus (Soapberry), Aesculus (buckeye), Ungnadia (Mexican buckeye). Acer (maple) has palmate compound lvs.
  • Rutaceae: (4-5;4-5;4-5, 8 10 or inf.) Glandular punctate lvs. Aromatic. Citrus family.
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