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Dichotomous Keys for Identification of Flora and Fauna of the Coastal Bend by Chad Huckabee
The Dichotomous Keys for Plants is taken from two sources: Plants of the Texas Coastal Bend by Roy L. Lehman, Ruth O’Brien and Tammy White, its precursor, and Plants of the Coastal Bend by Fred Jones. These dichotomous keys have been modified in several ways from their original sources. I have tried to eliminate plants that are not likely to be in Nueces County and the western and southern limits of the South Texas Chapter Master Naturalist, and I have attempted to reduce the technical jargon to a more user-friendly format. This being said, it is incumbent upon the user of these keys to access diagrams that display plant structures. These may be found in most plant ID books.
Why not utilize digital ID solutions and picture ID books? Simply, a serious investigation of plants will find both of these sources lacking. The former is only about 50% accurate, while the latter is very accurate but typically contains only “pretty” flowers. While these two sources are an ok starting point, they cannot be trusted in many cases. Plants in large genus, plants that are very small, even plants in large families such as Asteraceae are highly problematic when it comes to accurate identification. Certainly, a plant represented by a tiny handful of species within a genus will likely be identifiable by digital or book photo sources. However, utilizing sources such as iNaturalist, one must be very wary since one does not know who or where the identifier is. Always, take your identification to the next level. Is the identified plant in your area? Does your plant match its scientific description found in the dichotomous keys to some extent, but more thoroughly found within professional internet or text sources? Finally, realize that within the Coastal Bend of South Texas there are over 2000 species of plants. This does not include grasses. We live in a rich, highly diversified area of the world with many ecological variations due to weather, soil, and water salinity. Since plants are the base of the food chain for most living things, are we really Master Naturalists without a good understanding of plants?
- Plants with climbing or sometimes trailing stems: vine……………………………..…Key A
Plants NOT as above……………………………….…………………………..………………….…………..2 - Plants with woody stems: Trees and Shrubs…………………………………………………Key B
Plants NOT woody unless at the base: Herbs & Shrubs………………………..……………3 - Plants of aquatic or land habits that stay moist: Aquatic or Marsh……………Key C
Plants NOT as above…………………………………………………………………………………………..4 - Flowering plants attached to stems of trees or shrubs: Parasites or Epiphytes…………………………………………………………………………………………………………..…Key D
Flowering plants NOT as above……………………………………………………………….…………….5 - Stems and leaves spiny, prickly or stinging: …………………………………………………..Key E
Stems NOT as above……………………………………………….………….……………………………..6 - Flowers unisexual, the male and female on separate plants………………………Key F
Flowers NOT as above………………………………………………………………………………..………..7 - Perianth lacking or reduced to scales, bristles, or hairs……….…………………….Key G
Perianth well developed in some or all of the flowers…………………….……………….8 - Perianth NOT clearly differentiated into calyx and corolla or only the calyx present……………………………………………………………………………………………………………………Key H
Perianth clearly differentiated into calyx and corolla………………..………………………9 - Corolla with petals separate…………………………………………..…………..…………………..Key I
- Corolla with corolla partly or totally united……………………………………………………….Key J
Notes:
• Carefully examine plants to ensure the criteria is met.
• When you get to the term perianth, it is the outer part of the flower: the calyx (sepals) and the corolla (petals)
Key A: Vines (Revised Jan 2022)
- Stems leafless, yellow or orange……………………………..Cuscutaceae (Dodder)
Stems leafy………………………………………………………………………………………………..2 - Stems prickly, spiny, or stinging…………………………….…………………………………3
Stems NOT as above…………………………………………………………………………………..6 - Stems climbing with tendrils………………………………………..Smilacaceae (Sumac)
Stems without tendrils………………………………………………….…………………………….4 - Leaves simple………………………………………………………..Euphorbiaceae (Spurge)
Leaves compound…………………………………………………..…………………………………..5 - Leaves pinnate………………………………………………………………………Roseace (Rose)
Leaves bipinnate……………………………………………………………………Fabaceae (Pea) - Leaves opposite………………………………………………………………………….………………7
Leaves alternate…………………………………………………………………………………………12 - Leaves simple………………………………………………………………………………………………8
Leaves mostly or all compound……………………………………………………………….11 - Flowers are involucrate heads………………..………………………..Asteraeae (Aster)
Flowers NOT as above……………………………………………………………………………….9 - Stamens united…………………………………………………Asclepiadaceae (Milkweed)
Stamens separate……………………………………………………………………………………10 - Corolla tubular, bilabiate …………………………..…..Caprifoliaceae (Honeysuckle)
Corolla funnelform……………………………..………..Nyctaginaceae (Four-O-Clock) - Flowers whiteish or purple…………………….Ranunculaceae (Old Man’s Beard)
Flowers orange or red……………………………………….…Begoniaceae (Cross Vine) - Leaves simple…………………………………………………………..………………………………..13
Leaves compound…………………………………………………………….……………………….23 - Stems climbing by tendrils………………………………………………………………………14
Stems without tendrils……………………………………………………….……………………17 - Tendrils on petioles………………………………….……….…….Smilacaceae (Cat brier)
Tendrils axillary or opposite the leaves, NOT on petioles……………….………15 - Flowers in panicles……………………………………………………………Vitaceae (Grape)
Flowers NOT panicled…………………………………………………………………………….16 - Petals united……………………………………………..……………Cucurbitaceae (Gourd)
Petals separate……………………………………………..Passifloraceae (Passionflower) - Petals or tepals free from each other………….………………………………………….18
Petals united at least at the base……………………………………………………………..20 - Petals or tepals 5…………………………………………………….………………………………..19
Petals 6, sepals 6……………………………………….…Menispermaceae (Moonseed) - Petals or tepals 1.5 – 2 mm long, equal…………….…..Rhamnaceae (Buckhorn)
Petals more than 2 mm long, unequal……………….………………..Fabaceae (Pea) - Corolla regular………………………………………………………………………………………….21
Corolla irregular……………………………………………….Scrophulariaceae (Figwort) - Corolla deeply lobed…………………………………….……..Solanaceae (Nightshade
Corolla entire or shallow lobed……………….Convolvulaceae (Morning Glory) - Stems climbing by tendrils……………………………..……………………………………….23
Stems without tendrils………………………………..………………………………………….26 - Tendrils at tip of leaf axis…………………………………………………….Fabaceae (Pea)
Tendrils NOT as above……………………………..……………………………………………..24 - Tendrils mostly or all axillary…………………………………………………………………..25
Tendrils opposite the leaves………………………………………………Vitaceae (Grape) - Fruit winged or inflated……………………………………….Sapindaceae (Soapberry)
Fruit spiny……………………………………………………………….Cucurbitaceae (Gourd) - Flowers in panicles…………………………………………….…..Anacardiaceae (Sumac)
Flowers NOT panicled……………………………………………..………….Fabaceae (Pea)
Key B: Trees and Shrubs
- Leaves simple or lacking……………………………….…………………………..…………………2
Leaves compound……………………………………….………………………….………………….50 - Leaves scale-like, 1 – 3 mm long………………….……………….…………………………….3
Leaves NOT scale-like, well-developed……….……………..………………………………4 - Plants thorny…………………………………………………..…………Capparaceae (Allthorn)
Plants NOT as above, sessile, scale-like, alternate, leaves perfect flowers on spike, raceme. ……………………………………………………….. Tamaricavceae (Salt Cedar) - Leaves 2-ranked, fruit a cone………………..…………..Taxodinaceae (Bald Cypress)
Leaves and fruit NOT as above……………………..……………………………………………..5 - Leaves fan-shaped and pleated…………………………………………Arecaceae (Palms)
Leaves NOT as above………………………………………….………………………………………..6 - Leaves 30 cm or longer, sharp, pointed…………………………..Agavaceae (Agave)
Leaves NOT as above……………………………………………………………………………………7 - Leaves mostly or all opposite or whorled………………………..………………………….8
Leaves mostly or all alternate or bunched at nodes on spines……………….….19 - Plants growing as parasites on stems of trees and shrubs……………………………………………………………………………….…Viscaceae ( Mistletoe)
Plants rooted in soil………………………………………………………..…………………………..9 - Plants of wet salty soils along the coast……………………………………………………..10
Plants NOT of the above habitat………………………………………………….……………..12 - Leaves fleshy…………………………………………………………………….Bataceae (Saltwort)
Leaves NOT as above………………………………………………………….……………………….11 - Leaves whitish beneath……………………………..…Avicenniaceae (Black Mangrove)
Leaves green on both sides…………………………………………….…Asteraceae (Asters) - Perianth lacking………………………………………………………………………..Oleaceae (Olive)
Perianth present…………………………………………………..………………………………………13 - Corolla of separate petals……………………………..…………………………………………….14
Corolla of united petals……………………………………………………………………………….15 - Petals pink to reddish purple………………….…..Malpighiaceae (Barbados Cherry)
Petals greenish yellow or whitish…………..………………………..Rhamnaceae (Brasil) - Ovary inferior……………………………………………………..………Rubiaceae (Bottonbush)
Ovary superior………………………………………………………………….……………………………16 - Stamens 2………………………………………………………………………………….………………….17
Stamens 4……………………………………………………………….…….Verbenaceae (Verbina) - Leaves toothed…………………………………………………….……………….Lamiaceae (Mint)
Leaves entire………………………………………………………………………………………….………..18 - Plants reaching tree size reaching 15 m……………..….Boraginaceae (Wild Olive)
Plants shrubs reaching 1 m………………………………………..Acanthaceae (Acanthus) - Plants more or less thorny………………………………………………………………….………..20
Plants NOT as above……………………………………………………………………..……………..30 - Leaves are partly or all toothed or lobed………………………………………………….….21
Leaves entire……………………………………………………………………………………….………..24 - Perianth NOT differentiated into calyx and corolla OR only calyx present….22
Perianth differentiated into calyx and corolla……………………………………….……..23 - Leaves roughish; thorns mostly in pairs…………………………….……Ulmaceae (Elm)
Leaves smooth; toothed; thorns not paired……………………Moraceae (Mulberry) - Petals greenish-yellow……………………………………………….Rhamnaceae (Buckhorn)
Petals white………………………………………………………………..………….Roseaceae (Rose) - Perianth NOT differentiated into calyx and corrola………………………………………25
Perianth differentiated into calyx and corolla………………………………………………..27 - Sepals about 1 mm long, triangular………………..………..Rhamnaceae (Buckhorn)
Sepals about 2 mm long, oval or obovate……………Phytolaccaceae (Pokeweed) - Petals greenish-yellow…………………………………………………..Ramnaceae (Buckhorn)
Petals white…………………………………………………………..……………….Roseaceae (Rose) - Corolla of separate petals………………………………..……………………………………………28
Corolla of united petals, fertile stamens 4 or 5…………………………..………………….29 - Petals 4…………………………………………………………..………Simaroubaceae (Amargosa)
Petals 5…………………………………………………………….………….. Rhamnaceae (Buckhorn - Stamenoids (unfertile stamens) about 5……………….……….Sapotaceae (Ironwood)
Stamenoids lacking………………………………..Solenaceae (Nightshade) - Perianth lacking……………………………………………………………..……………………………….31
Perianth present………………………………………………………………..……………………………33 - Flowers in drooping globous heads……………….……..Platanaceae (Sea Lavender)
Flowers in catkins…………………………………………………..……………………………………….32 - Leaves dotted with yellow glands, aromatic…………..….Myricaceae (Wax Myrtle)
Leaves NOT as above…………………………………………………….…..Salicaceae (Willows) - Perianth NOT differentiated into calyx and corolla……….………………………………34
Perianth differentiated into calyx and corolla…………………….…………………………40 - Flowers in involucrate heads…………………………………………..….Asteraceae (Asters)
Flowers NOT as above………………………………..…………………………………………………35 - Flowers partly or all perfect……………………………………………………………………..……36
Flowers unisexual………………………………………………………………………………………..….37 - Styles one; leaves equilateral, evergreen…………………….…….. Lauraceae (Laurels)
Styles two; leaves NOT equilateral, deciduous………………………..Ulmaceae (Elms) - Male and female flowers on the same plant; the male in catkins or racemes.38
Male and female flowers on separate plants; pubescent stellate ……………………………………………………………………………….…….Euphorbiaceae (Spurge) - Female flowers solitary or few……………………………………………………………………….39
Female flowers in short spikes; fruits fleshy……………………..Moraceae (Mulberry) - Fruit an acorn…………………………………………………………………………….Fagaceae (Oak)
Fruit a dry capsule………………………………………….…………….Euphorbiaceae (Spurge) - Corolla of separate or nearly separate petals…………………………………………………41
Corolla of united petals…………………………………………………….…………………………….46 - Leaves entire…………………………………………………………………………..………………………..42
Leaves toothed or lobed…………………………………………………………………………………..43 - Leaves with stellate pubescence……………………………………Euphorbiaceae (Spurge)
Leaves glabrous……………………….…………………………….Celastraceace (Leather Leaf) - Stamens 4 – 5……………………………………………………………………………..…………………..44
Stamens more than 5…………………………………………………………………….………………..45 - Sepals densely hairy………………………………………………..……..Rhamnaceae (Buckhorn)
Sepals glabrous or nearly so…………………………………..………….Aquifoliaceae (Holly) - Filaments united to for a tube around the style………………..….Malvaceae (Mallow)
Filaments separate……………………………………………………………….…..Roseaceae (Rose) - Flowers unisexual, the male and female on separate plants…………………………..47
Flowers perfect………………………………………………………………………………………………….48 - Plant a shrublet with smooth pliable stems…………………..Euphorbiaceae (Spurge)
Plant a tree or large shrub……………………………………………..Ebenaceae (Persimmon) - Leaves rough; ovary superior……………………………………. Boraginaceae (Wild Olive)
Leaves smooth…………………………………………………………………………………………………49 - Leaves densely pubescent……………………………………………Scrophularaceae (Figwort)
Leaves glabrous…………………………………………………….………Solanaceae (Nightshade) - Leaves opposite……………………………………………………..………………………………………….51
Leaves alternate…………………………………………………………..…………………………………….54 - Leaflets 5 – 14 mm long……………………………………….……….Zygophyllaceae (Caltrop)
Leaflets much longer……………………………..…………………………………………………………52 - Plant a shrub……………………………………………………..……..Caprifoliaceae (Honeysuckle)
Plant a tree………………………………………………………………………….……………………………..53 - Leaflets usually 3 – 5; coarsely toothed………………………………….….Aceraceae (Palm)
Leaflets usually 5 – 7; shallowly toothed or entire……………….……..Oleaceae (Olive) - Stems prickly or spiny……………………………………………………………….……………………….55
Stems NOT as above……………………………………………………..…………………………………57 - Leaflets toothed………………………………………………………………………………………………….56
Leaflets entire…………………………………………………………………………….…Fabaceae (Peas) - Flowers clustered, yellow-green………………………………………………….Rutaceae (Citrus)
Flowers mostly solitary, white……………………………………………………Roseaceae (Rose) - Leaflets prickly………………………………………………………………….Berberiaceae (Barberry)
Leaflets NOT prickly……………………………………………………….………………………………….58 - Leaflets toothed or lobed…………………………………………………………………………………….59
Leaflets entire…………………………………………………………………………………………………….63 - Leaflets 3…………………………………………………………………………..………………………………60
Leaflets more than three…………………………………………………………………..………………..61 - Leaflets 0.6 – 3 cm long……………………………………………………………..Rutaceae (Citrus)
Leaflets 3 – 20 cm long…………………………………………….……..Anacardiaceae (Sumac) - Leaves pinnate…………………………………………………………………………………………………62
Leaves bipinnate………………………………………………………………Meliaceae (Mahogany) - Leaflets 5 – 7……………………………………………………………….. Sapindaceae (Soapberry)
Leaflets 9 – 13……………………………………………………….Juglandaceae (Walnut) - Leaflets 2 or 3……………………………………………………….………………………………………….64
Leaflets more than 3………………………………………………………..………………………………66 - Leaflets 2………………………………………………………………………………………Fabaceae (Pea)
Leaflets 3…………………………………………………………………………………………….……………65 - Plant a low shrub or climbing vine…………………………….…..Anacardiaceae (Sumac)
Plant a small tree…………………………………………………….………………..Rutaceae (Citrus) - Petioles winged……………………………………………………….………Anacardiaceae (Sumac)
Petioles NOT winged……………………………………………..…………………………………………67 - Leaflets narrow to a point……………………………………..………Sapindaceae (Soapberry)
Leaflets NOT pointed……………………………………………………………………..Fabaceae (Pea)
Key C: Aquatic and Marsh Plants
- Plants floating free or merely lodged, NOT taking root…………………………………………………………………………….…………..Lemnaceae (Duckweed)
Plants rooted in the bottom, on muddy shores or where water has receded……………………………………………………………………………………………………………………….….2 - Plants wholly submerged or only he flowers raised to the surface……………….……3
Plants partly submerged or NOT at all………………………………………………..……………..7 - Plants of fresh or brackish water………………………………………………..……………………….4
Plants of marine salinities……………………………………………………………………………………………..…………………5 - Leaves opposite or subopposite, whorled to 4 cm long………………………………………………………………………….. Hydrocharitaceae (Turtle Grass)
Leaves mostly or all alternate……………….……………..….Ruppaceae (Widgeon Grass) - Leaves 0.4 – 2 mm wide, linear……………………………………………………………………..…….7
Leaves broader……………………………………………………Hydrocharitaceae (Turtle Grass) - Fruits stipulate, several per bundle…………………………Ruppiaceae (Widgeon Grass)
Fruits NOT as above……………………………………….…….Cymodoceaceae (Shoal Grass) - Leaves lacking or reduced to scales or sheaths…………………….……………………………8
Leaves well developed………………………………………………………………………………………10 - Stems jointed……………………………………………………………………………………………………….9
Stems Not jointed…………………………………………………………………Cyperaceae (Sedge) - Stems fleshy………………………………………………………………Chenopodiaceae (Pigweed)
Stems hollow, NOT fleshy………………………………………….……Equisetaceae (Horsetail) - Leaves partially or all compounded or dissected or umbels……….……………………11
Leaves simple, toothed or entire, NOT dissected…………………….……………………….14 - Flowers in umbels………………………………………………………………….…..Apiaceae (Carrot)
Flowers NOT in umbels………………………………………………………….…………………………..12 - Flowers yellow…………………………………………………………………………..………………………13
Flowers NOT yellow, leaves opposite…………………………Scrophulariaceae (Figwort) - Petals 1.5 – 2 mm long……………………………………………………..Brassicaceae (Mustard)
Petals longer………………………………………………………………….………………Fabaceae (Pea) - Perianth lacking or reduced to scales, bristles or threads……………………….…………15
Perianth present…………………………………………………………………………………..……………19 - Leaves mostly alternate or basal, leaf sheathing the stem, linear……….……………16
Leaves mostly or all opposite……………………………………………………………….…………..18 - Sheaths usually open on one side…………………………………………………………………….17
Sheaths closed………………………………………………………………….…..Cyperaceae (Sedge) - Stems jointed……………………………………………………………………………….Poaceae (Grass)
Stems NOT jointed……………………………………………………………….Typhaceae (Cat-tail) - Plants of salt marshes……………………………………………………….……Bataceae (Saltwort)
Plants of fresh water or mud…………………………………………………………………………….22 - Perianth NOT clearly differentiated into calyx and corolla or either the calyx OR corolla lacking…………………………………………………………………………..………………………20
Perianth differentiated into calyx and corolla, the calyx sometimes modified…………………………………………………………………………………………..……………..31 - Leaves thick, fleshy; plants of brackish or salty soils……………………………………….21
Leaves NOT thick, fleshy…………………………………………………………………………………..24 - Leaves alternate……………………………………………………….Chenopodiaceae (Pigweed)
Leaves opposite………………………………………………………………………………………………22 - Flowers solitary…………………………………………….…………….Aizoaceae (Sea Purslane)
Flowers in spikes…………………………………………………………….………………………………23 - Flowers unisexual………………………………………….……………….……Bataceae (Saltwort)
Flowers perfect……………………………………………………Amaranthaceae (Amaranthus) - Stems rooting at nodes……………………………………..…….……………………………………..25
Stems NOT as above………………………………………………………………………………………26 - Flowers solitary…………………………………………….. Pontederiaceae (Water Hyacinth)
Flowers clustered…………………………………………………………………….Apiaceae (Carrot) - Ovary superior……………………………………………………..…………………………………………27
Ovary inferior…………………………………………………………………….……………………………..29 - Leaves parallel-veined…………………………………………………….………………………………28
Leaves net-veined………………………………………………………Polygonaceae (Buckwheat) - Perianth corolla-like, conspicuous…………….…….Pontederiaceae (Water Hyacinth)
Perianth scale-like, inconspicuous………………………..…………………Juncaceae (Rush) - Perianth of 4 tepals……………………………………………Onagraceae (Evening Primrose)
Perianth of 6 tepals…………………………………………………………………………………………..30 - Tepals blue to violet…………………………………………….………………………..Iridaceae (Iris)
Tepals white or yellow……………………………………………….…………………..Liliaceae (Lily) - Leaves all basal……………………………………………………………………..…………………………..32
Leaves NOT basal ……………………………………………………………………….………………….34 - Corolla of separate petals………………………………………………………………………….…….33
Corolla of united petals……………………………………………Plumbaginaceae (Leadwort) - Flowers solitary…………………………………………………………Ranunculaceae (Buttercup)
Flowers in whorls…………………………………………………..Alismataceae (Waterplantain) - Leaves 15 – 20 cm wide…………………………………………………………Cannaceae (Canna)
Leaves much narrower……………………………………………………………………………………..35 - Leaves alternate………………………………………………………………………………….…………….43
Leaves opposite or whorled………………………………………………….…………………………36 - Corolla of separate petals………………………………………………………………..……………….37
Corolla of united petals…………………………………………………………………………..……….39 - Corolla regular…………………………………………………………………………………………………38
Corolla irregular…………………………………………………………….……Orchidaceae (Orchid) - Filaments united into tubes…………………………………….…………..Malvaceae (Mallow)
Filaments separate…………………………………………………………….……………………………..39 - Ovary inferior……………………………………………………..Onagraceae (Evening Primrose)
Ovary superior………………………………………………….………………………………………………41 - Pistil 1…………………………………………………………………………….. Lythraceae (Loosestrife)
Pistils several……………………………………………………..……..Ranncularaceae (Buttercup) - Flowers in heads, anthers united into a tube………………………….Asteraceae (Aster)
Flowers NOT in heads………………………………………………………………….…………………….42 - Flowers in unrolling spikes……………………………………….……..Boraginaceae (Borage)
Flowers NOT in spikes………………………………………………….Primularaceae (Primrose) - Ovary inferior………………………………………………………………..………………………………….44
Ovary superior……………………………………………………………………………….……………….. 45 - Anthers united into a tube around the style…………………………..Asteraceae (Aster)
Anthers separate……………………………………………………………..……Rubiaceae (Madder) - Leaves toothed…………………………………………………………………………..Lamiaceae (Mint)
Leaves entire……………………………………………………………………………………………………..46 - Corolla lobes 1.5 – 3 cm long…………………………………………Gentianaceae (Gentian)
Corolla lobes shorter…………………………………………………………..……………………………47 - Flowers in peduncled heads………………………………………..Acanthanceae (Acanthus)
Flowers in racemes or on axillary pedicles………………..Scrophulariaceae (Figwort)
Key D: Epiphytes and Parasites
- Plants are epiphytes…………………………………………………….. Bromeliaceae (Pineapple)
Plants are parasites…………………………………………………..………………………………………2 - Plants with leafless stems, yellow or orange (a parasite) ………………………………………………………………………………………….. ……Cuscutaceae (Dodder)
Leaves obovate ellipse………………………………………………..…….Viscaceae (Mistletoe)
Key E: Stems and often leaves spiny, prickle, or stinging.
- Stems with stinging hairs or bristles…………………………………………………………………..2
Stems spiny or prickly……………………………………..…………………………………………………3 - Leaves opposite ……………………………………………………… Urticaceae (Stinging Nettle)
Leaves alternate……………………………………………………………Euphorbiaceae ((Spurge) - Stems thick fleshy; leaves lacking or present only on young stems…………………………………………………………………….………………..Cactaceae (Cactus)
Stems NOT as above………………………………………………………………………………………….4 - Leaves opposite………………………………………………………………Verbenaceae (Verbena)
Leaves alternate…………………………………………………………………………………………………5 - Leaves simple……………………………………………………..…………………………………………….. 6
Leaves compound or with 1 – 2 pentified…………………………………………………………. 8 - Leaves with prickly margins………………………………………………Papaveraceae (Poppy)
Leaves NOT as above…………………………….………………………………………………………….7 - Flowers in dense clusters………………………………………….Amaranthaceae (Goosefoot)
Flowers solitary or few together……………………….…………..Solanaceae (Nightshade) - Flowers in dense heads………………………………………………………………..Fabaceae (Pea)
Flowers NOT as above………………………………………………………………………………………..9 - Petals separate………………………………………………….……………………..Roseaceae (Rose)
Petals united……………………………………………………………..…Solanaceae (Nightshade)
Key F: Flowers unisexual, Male and female on separate plants
- Leaves reduced to scales……………………………………………………………..Liliaceae (Lily)
Leaves well developed……………………………………………………………………………………..2 - Leaves opposite…………………………………………………………………………….…………………3
Leaves mostly or all alternate, sometimes branched on sort spurs……………..…..4 - Leaves 4-8 mm long……………………………..……………….Chenopodeaceae (Pigweed)
Leaves much longer…………………………………………..…..Amaranthaceae (Goosefoot) - Stipules united to form a tubular sheath………………….Polygonaceae (Buckwheat)
Stipules NOT as above often lacking……………………………………………………………….5 - Plants glabrous…………………………………………………………….Euphorbiaceae (Spurge)
Plants NOT as above……………………………………………………………………………………….6 - Plants pubescent with simple or branched hair………….Euphorbiaceae (Spurge)
Plants mealy or scaly……………………………………………..………………………………………..7 - Leaves mostly wavy edged, coarsely toothed or basally lobed ……………………………………………………………………………..Chenopodiaceale (Pigweed)
Leaves entire……………………………………………………………….Euphorbiaceae (Spurge)
Key G: Perianth Lacking or Reduced to Scales, or Bristles
- Plant with single compound leaf, flowers in a spadix…………….Areaceae (Palm)
Plant with more than one leaf…………………………………………………………….………….2 - Leaves reduced to sheaths……………………………….…………….Cyperaceae (Sedges)
Leaves with well-developed blades……………………………………………………………….3 - Flowers in cuplike involucre type having a gland around its ……………………………………………………………………………………..…….Euphorbiaceae (Spurge)
Flowers NOT as above…………………………………………………..……………………………….4 - Stems jointed, sheaths open on one side……………………….. Poaceae ( Grasses)
Stems NOT jointed, sheaths closed……………………………….Cyperaceae (Sedges)
Key H: Perianth NOT Clearly Differentiated into Calyx and Corolla
- Ovary inferior or partially inferior…………………………………………………………..…….2
Ovary superior…………………………………………………………………..………………………..11 - Flowers in heads subtended by an involucre of bracts…….…………………………..3
Flowers NOT as above………………………………………………………………………..………….5 - Anthers united into a tube around the style………………………Asteraceae (Aster)
Anthers distinct……………………………………………………………………………………………4 - Flowers perfect……………………………………………….Nyctaginaceae (Four-O-Clock)
Flowers unisexual……………………………………………………………….Asteraceae (Aster) - Leaves opposite or whorled…………………………………………………..……………………..6
Leaves alternate or basal……………………………………………………………..………………..7 - Leaves opposite, NOT in whorled………….………Nyctaginaceae (Four-O-Clock)
Leaves whorled………………………………………………………..……..Rubiaceae (Madder) - Perianth regular or only slightly irregular………………………..…………………….……..8
Perianth strongly irregular, tubular.…………………….Aristolochiaceae (Pipevine) - Perianth segments (tepals)……………………………………..……………………………………9
Perianth segments (petals)…………………..………………………..……………….Apiaceae (Carrot) - Stamens 3, sometimes with united stamens……………………………..Iridaceae (Iris)
Stamens 6…………..…………………………………………………………………………….…………10 - Flowers solitary or in umbels……………….……………………………….……Liliaceae (Lily)
Flowers in racemes……………………………………….…………………..Agavaceae (Agave) - Leaves opposite, or whorled (part may be basal)………………………………….……12
Leaves alternate or basal…………………………………………………………………………….15 - Leaves palmately compound with 3 toothed or lobed leaflets……………………………………………………………..…….Ranunculaceae (Buttercup)
Leaves simple, entire or subentire…………………………………………………..………….13 - Ovary tightly enclosed by perianth………………….Nyctaginaceae (Four-O-Clock)
NOT as above…………………………………………………………………………..……………………….14 - Stipules present…………………………………………………….…..Aizoaceae (Sea Purslane)
Stipules NOT present………………………………………..….Amaranthaceae (Amaranth) - Leaves palmately compound with 3……………………..Ranunculaceae (Buttercup)
Leaves simple, entire (or sometimes toothed or basal)………………………….……16 - Stipules united to forma tubular sheath……………….Polygonaceae (Buckwheat)
Stipules NOT as above………………………………………………….………………………………17 - Flowers unisexual………………………………………………………………………………………….18
Flowers all perfect (or part of them unisexual)………………………………………………21 - Perianth lacking in female flowers; fruits enclosed by a pair of thick or hardened bract………………………………………………………..Chenopodiaceae (Pigweed)
Perianth present in both male and female flower…………….…………………….…….19 - Leaves toothed or lobe.…………………………………..………….Euphorbiaceae (Spurge)
Leaves entire………………………………………………………………..………………………………..20 - Flowers in dense clusters; fruits 1 seeded………..…Amaranthaceae (Amaranth)
Flowers few or solitary; fruits with several seed………..Euphorbiaceae (Spurge) - Leaves variously toothed or lobed; tepals 1 – 5 …………………………………………………………………………….……..Chenopodiaceae (Pigweed)
Leaves entire…………………………………………………………………..…………………………..22 - Flowers in racemes……………………………………………….Phytolaccaceae (Pokeberry)
Leaves NOT in racemes………………………………………………………………………………….23 - Tepals usually 4 – 5……………………..………………………………………………………………..24
Tepals 6……………………………………………………………………………………………….………..26 - Tepals 4; flowers polygamous…………………………………………….Urticaceae (Nettle)
Tepals 5 (rarely 4); flowers perfect………………………………………………………………..25 - Fruits 1 – seeded……….………………………………………….Chenopodiaceae (Pigweed)
Fruits several seeded….……………………………….………..Amaranthaceae (Amaranth) - Leaves white beneath; stamens 9..…………………….…..Polygonaceae (Buckwheat)
Leaves green on both sides……………………………………..…………………………………..27 - Tepals petal-like…………………………………………………………………………Liliaceae (Lily)
Tepals scale-like……………………………………….……………………….…..Juncaceae (Rush)
Key I: Perianth Clearly Differentiated into Calyx and Corolla: Petals separate
- Corolla strongly irregular……………………………………………………………………………….2
Corolla regular or slightly irregular……………………………………………………………….9 - Ovary inferior………………………………………………. Onagraceae (Evening Primrose)
Ovary superior…………………………………………….………………………………………………..3 - Leaves deeply lobed, dissected or compound……………………………………………..4
Leaves entire or toothed, simple……………………………………………….………………….7 - Calyx petal-like; upper sepal spurred at base………Ranunculaceae (Buttercup)
Calyx NOT as above…………………………………………………….…………………………………5 - Calyx of tiny sepals; petals slightly fused at tip……….Fumariaceae (Fumatory)
Calyx 0f 4 – 5 separate or united sepals…………………………………………..…………..6 - Sepals 4; petals 4………………………………………………………..Capparaceae (Allthorn)
Sepals 5; petals 5 or fewer………………………………………………………Fabaceae (Pea) - Sepals 3, these 1- 3.5 mm long (two additional sepals longer and petal-like)…………………………………………………………………..…….Polygonaceae (Buckwheat)
Sepals 4 – 6, usually 5……………………………………………………..……………………………8 - Sepals united below……………………………………………..……………….Fabaceae (Pea)
Sepals separate or nearly so; stamens 5………………………..….Violaceae (Violet) - Ovary inferior or partially inferior……………………………………………………………….10
Ovary superior……………………………………………………………………….……………………13 - Petals 4; stamens 8……………………………………………………. Onagraceae (Primrose)
Petals 5………………………………………………………………………………………………………..11 - Sepals or calyx lobes 2; lobes 2; stamens 8 – 20 or more ……………………………………………………………………………………..…..Portulacaceae (Purslane)
Sepals or calyx lobes 5 or lacking……………………………………………..………………..12 - Flowers umbels …………………………………………………………………..Apiaceae (Carrot)
Flowers otherwise…………………………………………………………………….…………………13 - Leaves mostly or all opposite, or part of them whorled……………………………..14
Leaves mostly or all alternate, subopposite or basal………………….……………….16 - Leaves compound or deeply lobed……………………………………………………..……….15
Leaves simple, entire Petals narrowed to a petiole-like base…………………………………………………………..……Malpighiaceae (Barbados Cherry) - Leaves compound…………………………………………………….Zygophyllaceae (Caltrop)
Leaves deeply lobed…………………………………………………..Geraniaceae (Geranium) - Flowers unisexual……………………………………………………..Euphorbiaceae (Spurge)
Flowers perfect……………………………………………………………………..……………………..17 - Petals 3 or 4……………………………………………………………………………………..………….18
Petals 5 or sometimes more……………………………………………….………………………20 - Petals 3; sepals 3 or 5…………………………….…. Commelinaceae (Morning Glory)
Petals 4; sepals 4………………………………………………………………………………………..19 - Fruits strongly 2 lobed………………………………..………………………Rutaceae (Citrus)
Fruit NOT as above……………………………………………….….Brassicaceae (Mustard) - Stamens united by their filaments into tube around the style; stamens more than 5…………………………………………………………………………….Malvaceae (Mallow)
Stamens separate or filaments united below……………………………………………21 - Leaves palmately lobed; petals white, pink or purple……………………………………………………………………..……..Geraniaceae (Geranium)
Leaves entire…………………………………………………………………………………………..…..22 - Leaves compound……………………………………………………………………..………………23
Leaves simple, entire…………………………………………………………………………..……..24 - Style 1…………………………………………………………………………………….Fabaceae (Pea)
Style 5………………………………………………………………….Oxalidaceae (Wood Sorrel) - Sepals or calyx lobes 2; styles 3………………………….……Portulacaceae (Purslane)
Sepals or calyx lobes 5 – 6…………………………………….……………………………………25 - Stamens 10 or more Flowers solitary…………..………Oxalidaceae (Wood Sorrel)
Stamens fewer than 10…………………………………………………………………………..…..26 - Styles 1………………………………………………………….…………….Lythraceae (Loosestrife)
Styles 5……………………………………………………………………..……………….Linaceae (Flax)
Key J: Perianth Clearly Differentiated; Petals Partly or Wholly United
- Ovary inferior or partly inferior………………………………………………………………..……2
Ovary superior…………………………………………………………………………………………..…..4 - Anthers united into a tube around the style…………….………..Asteraceae (Aster)
Anthers separate……………………………………………………………..…………………………….3 - Flowers unisexual……………………………………..………………………..Asteraceae (Aster)
Flowers perfect……………………………………………..………………..Rubiaceae (Madder) - Leaves reduced to bracts; corolla regu………Convolvulaceae (Morning Glory)
Leaves well developed…………………………………………………………….…………………….5 - Leaves compound………………………………………………………………………………………..6
Leaves simple…………………………………………………………………………….…………………8 - Styles or stigma 2……………………………………………..Hydrophyllaceae (Waterleaf)
Styles 1………………………………………………………………………………………..……………….7 - Fruit a berry……………………………………………………………Solanaceae (Nightshade)
Fruit NOT a berry……………………………………………………………………Fabaceae (Pea) - Leaves all basal……………………………………………………………………………………………9
Leaves NOT as above………………………………………………………………………….…….10 - Corolla 4 lobed………………………………………………..……Plantaginaceae (Plantain)
Corolla 5 lobed………………………………………………………….Acanthaceae (Acanthus) - Leaves opposite or whorled, or the middle and upper alternate…………..…11
Leaves alternate……………………………………………………………………………………..…30 - Corolla distinctly irregular…………………………………………………………………………12
Corolla regular…………………………………………………………………………………………..25 - Stamens 2…………………………………………………………………………………………………..13
Stamens 4…………………………………………………………………………………………………..17 - Leaves generally toothed…………………………………………………………………………….14
Leaves entire………………………………………………………………………………………………15 - Corolla 2-lipped………………………………………………………………….Lamiaceae (Mint)
Corolla 4-lobed…………………………………………………..Scrophulariaceae (Figwort) - Corolla yellow………………………………………………….Schrophulariaceae (Figwort)
Corolla NOT yellow…………………………………………………………………………………..16 - Ovary 4-lobed around the style; fruit of a4 nutlets………..…Lamiaceae (Mint)
Ovary and fruit NOT as above…………….………………….Acanthaceae (Acanthus) - Leaves entire or wavy-margined…………………………………………..…………………..18
Leaves partly or all toothed or variously lobed…………………………..…………….20 - Calyx with protuberance on top ………………………………………..Lamiaceae (Mint)
Calyx lobes usually without protuberance………………………….……………………..19 - Calyx lobes 1-7 mm long……………………………..……..Scrophulariaceae (Figwort)
Calyx lobes usually more than7 mm long………………..Acanthaceae (Acanthus) - Leaves white and wooly………………………………….……Scrophulariaceae (Figwort)
Leaves NOT white…………………………………………………………………………….………….21 - Corolla 2-lipped or the upper lip missing……………………………………………..……..22
Corolla slightly if at all 2-lipped…………………………………………………………………..23 - Leaves usually aromatic; ovary 4-lobed, fruit of 4 nutlets..….Lamiaceae (Mint)
Leaves, ovary and fruit NOT as above…………………..Scrophulariaceae (Figwort) - Flowers in panicles………………………………………………….…Acanthaceae (Acanthus)
Flowers NOT as above…………………………………………………………………………………24 - Flowers mostly on peduncles 1-2 mm long…………Scrophulariaceae (Figwort)
Flowers in heads or spikes……………………………………………Verbenaceae (Vervain) - Stamens 2…………………………………………………………..……………………………………….26
Stamens 5………………………………………………………………..………………………………….27 - Corolla white or blue………………………………………….…Scrophulariaceae (Figwort)
Corolla yellow…………………………………………………..…………………..Oleaceae (Olive) - Stems with milky juice…………………………………..…… Asclepiadaceae (Milkweed)
Stems with watery juice……………………………………………………………………………….28 - Stigmas 2 or 3…………………………………………………………………………………………….29
Stigmas 1…………………………………………………………..….. Primulariaceae (Primrose) - Stigmas 2……………………………………….………………………….Gentianaceae (Gentian)
Stigmas 3……………………………………………………………….…..Polemoniaceae (Phlox) - Corolla irregular…………………………………………………………………………………………31
Corolla regular……………………………………………………………………………………….…..32 - Flowers in spikes; stamens 4………………………………..Scrophularaceae (Figwort)
Flowers NOT as above…………………………………………..……………….Fabaceae (Pea) - Stems with milky juice; filaments united into a column around the 2 pistils ……………………………………………………………………..…….Asclapiadaceae (Milkweed)
Stems with watery juice………………………………………………..……………………………33 - Leaves partly or all toothed, incised or variously lobed……….……………………34
Leaves entire or wavy margined…………………………………………………………………37 - Styles and stigmas 2 or 3………………………………………………….………………………..35
Styles and stigmas 1 or 4……………………………………………….…………………………..36 - Styles and stigmas 2…………………………………………Hydrophyllaceae (Waterleaf)
Styles and stigmas 3…………………………………..………………Polemoniaceae (Phlox) - Style and stigma 1………………………………………………….Solanaceae (Nightshade)
Styles and stigmas 4………………………………………………….Boraginaceae (Borage) - Styles, stigmas 2, 3 or 4……………………………………………………………………………..38
Style and stigma 1……………………………………………………………………….…………….42 - Styles and stigmas 2 or sometimes 3………………………………………………………..39
Styles or stigmas 4……………………………..………Convolvulaceae (Morning Glory) - Leaves at least as broad as long…………………Convolvulaceae (Morning Glory)
Leaves longer than broad………………………………………………………………………….40 - Stamens protruding beyond corolla……….…Convolvulaceae (Morning Glory)
Stamens NOT as above………………………………………………………………………………..41 - Leaves gray, felty, usually 8-10 mm long………….………..Boraginaceae (Borage)
Leaves green, mostly 10 mm or longer…………….Hydrophyllaceae (Waterleaf) - Corolla 8-10 cm long and as wide…………..… Convolvulaceae (Morning Glory)
Corolla much smaller…………………………………………………………………………………..43 - Calyx tube much less than 1 mm long or apparently lacking, the lobes either with stiff pointed hairs, or glabrous…………………….……….Boraginaceae (Borage)
Calyx tube 1-7 mm long, the lobes never with stiff pointed hairs…..…………44 - Calyx with hooked hairs………………………………………..…….Boraginaceae (Borage)
Calyx without hooked hairs…………………………….……….Solanaceae (Nightshade)
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