| 1. First true leaves
alternate |
|
| 1.
True leaves heart shaped |
|
| 1. True leaves
densely hairy |
|
|
1. Cotyledons oval to round |
Velvetleaf, Abutilon theophrasti |
2. True leaves
hairless to sparsely hairy;
cotyledons butterfly-wing shaped |
Tall Morningglory, Ipomea purpurea |
| 2.
True leaves lobed, spade, star, pentagon shaped |
|
| 1. True leaves
lobed |
|
1. All leaves lobed (first leaf slightly), cotyledons
butterfly-wing shaped |
Ivyleaf Morningglory, Ipomea
hederacea |
| 2. True leaves
spade, arrowhead, star, pentagon shaped |
|
|
1. True leaves with ochrea |
|
|
1. Cotyledons lanceolate to elliptic |
Wild buckwheat, Polygonum
convulvulus |
|
2. True leaves without ochrea |
|
1. True leaves spade shaped; cotyledons
kidney-bean shaped |
|
|
1. True leaf margins parallel; leaf tip blunt |
Field Bindweed, Convulvulus
arvensis |
2. True leaf margins with distinct edges and
not parallel; leaf tip pointed |
Hedge Bindweed, Calystegia sepium |
2. True leaves star or pentagon shaped;
cotyledons large, spoon shaped |
|
|
1. True leaves star shaped |
Wild Cucumber, Echinocystis lobata |
|
2. True leaves pentagon shaped (five sided) |
Burcucumber, Sicyos angulatus |
| 3. True leaves oval,
lovate, elliptic, lanceolate, spoon shaped |
|
|
1. True leaves spoon shaped; cotyledons kidney-bean shaped |
Mustard species |
|
2. True leaves lanceolate to elliptic |
|
|
1. Distinctive odor when crushed |
|
|
1. Cotyledon midrib prominent |
Jimsonweed, Datura stramonium |
|
2. Plants with ochrea; no odor |
Pennsylvania Smartweed, Polygomum
pensylvanicum |
|
3. True leaves ovate |
|
1. True leaves covered with mealy white
granules or frost |
Common Lambsquarters, Chenopodium
album |
|
2. True leaves without white granules or frost |
|
|
1. True leaves with notched tip, reddish undersides |
Smooth Pigweed or Redroot Pigweed,
Amaranthus sp. |
|
2. True leaves without notched tip |
|
1. Spines or thorns present on petioles, midrib, and
stems; perennial |
Horsenettle, Solanum carolinense |
2. No spines or thorns present on petioles,
midrib, or stem |
|
1.
True leaves sparsely to densely hairy with
pointed tip |
|
1. Leaf underside purple; cotyledons small and
ovate |
Eastern Black Nightshade, Solanum
ptycanthum |
|
2. True leaves smooth to sparsely hairy |
|
1. Stem purple; cotyledons if present small and
ovate; perennial |
Smooth Ground Cherry, Physalis
subglabrata |
| 1. First true leaves
opposite |
|
| 1.
True leaves lobed |
|
1. True leaves with
three to five major lobes; plants as large as a
silver
dollar at two-leaf stage |
Giant Ragweed, Ambrosia trifida |
2. True leaves with
greater than five major lobes, lacy; plants
as large as
a quarter at two-leaf stage |
Common Ragweed, Ambrosia
artimesiifolia |
| 2.
True leaves not lobed |
|
| 1. True leaves
densely hairy, later leaves alternate |
Common Sunflower, Helianthus
annuus |
| 2. True leaves
hairless or sparsely hairy |
|
|
1. True leaves covered with white mealy granules |
Common Lambsquarters, Chenopodium
album |
|
2. True leaves without white granules or frost |
|
1. True leaves rough textured; leaves alternate after
first true leaves; cotyledons thick and waxy |
Common cocklebur, Xanthium
strumarium |
2. True leaves smooth, waxy, may be slightly hairy;
sap milky |
|
|
1. Cotyledons, if present, lanceolate to elliptic |
Hemp Dogbane, Apocynum cannabinum |
|
2. Cotyledons, if present, oblong |
Common Milkweed, Asclepias syriaca |
