Keys

Life would be wonderful if we could identify all plants easily, merely from a series of photographs. Unfortunately life is rarely that simple it seems and, though this guide helps with the identification of many plants from photographs, some groups require closer inspection; a systematic way in which to separate similar-looking plants is required. Experienced botanists will be familiar with the idea of using keys to do this.

There are several different types of key that are used for identifying plants, but the most commonly-encountered and probably the easiest to use, are what are known as dichotomous keys. Such keys rely on setting out a series of identification criteria, which are laid out in couplets; these couplets essentially offer you a choice, based on features of the plant that can be studied readily. You pick the one that is right for your plant, and so you proceed through the key until you come to a single species.

If you are completely at a loss in trying to identify a plant - or are new to the subject - you can work your way right through the keys, starting at the very beginning with the Primary Key on this page. Gradually, you will acquire knowledge which, in the future, will allow you to jump through the early stages, eventually turning straight to the single family or genus keys to confirm what you might already suspect.

Remember, even keys are not a one-stop fix for everything and they need to be based on something. Most keys include flower structure and so you will often find that the plant needs to be in flower for it to be identified in this way. While this can be frustrating when faced with a plant that is not in flower, the best way to proceed with plant identification is to learn the plants when they are in flower, then re-visit the same individuals at other times of year to learn what the fruits, winter twigs or other relevant parts might look like. However, given the right time of year, these keys should enable you to identify any plant you might come across, growing uncultivated in southern New Jersey

Important Note: The keys only include species that have been recorded in Cape May or neighboring counties in southern New Jersey. Care should therefore be taken if using these keys outside of this area, as there may be other species present that are not included in the keys.

Primary Key to the Plants of Southern New Jersey

1. No flowers; reproduction by spores (ferns and their allies).
2. Sporangia (spore cases) born under the scales of a terminal, cone-like spike. Stems conspicuously jointed, the nodes covered by toothed
sheaths........................................................................................................................................................................................... Horsetails
2. Sporangia not as above.
3. Sporangia born in the axils of the crowded, lanceolate or subulate leaves, or of reduced scale-like leaves which form an erect spike.
Plants moss-like, often branched and trailing over the ground............................................................................................. Clubmosses
3. Sporangia not as above.
4. Sporangia born at the base of slender, awl-shaped, rush-like leaves, which grow in a tuft from a round, fleshy base rooting in the
mud. Plants submerged.......................................................................................................................................................... Quillworts
4. Sporangia born on the back of a leaf (frond) in round, elongated or marginal patches (sori); or in a spike or cluster on the modified
terminal (or middle) portion of the frond, or on a separate stalk arising from the ground (really a modified frond)................ Ferns
1. Woody trees and shrubs, or herbaceous forbs with true flowers present; containing stamens, pistils or both; reproduction by seeds.
5. Trees with needle-like, usually stiff, leaves; fruit, an elongated, woody cone................................................................... Pines & Spruces
5. Not as above.
6. Trees with scale-like, leathery leaves, overlapping each other and covering the stem; or with short, needle-like leaves. Fruit, a spherical
cone or a woody or fleshy berry............................................................................................................................ Junipers & Cypresses
6. Not as above.
7. Parts of the flower usually in threes or sixes, leaves mostly parallel-veined, often grass-like. Early leaves never opposite. In woody
plants, stem not divided into bark, wood and pith............................................................................................ Key A - Monocotyledons
7. Parts of the flower mostly in fours and fives, leaves net-veined. In woody plants, stem divided into bark, wood and pith, the wood in
perennial species growing by annual layers just under the bark........................................................................... Key B - Dicotyledons

Key A - Monocotyledons

The monocotyledons include all of our grasses, rushes, sedges and related plants; bulbous species such as lilies, onions etc; yuccas; irises; orchids, as well as a number of water plants.

1. Petalless flowers inclosed, or spikes of flowers surrounded by, overlapping husk-like scales (glumes); plants grass-like.
2. Stems hollow, round or flattened in cross-section but not triangular, anthers attached by the middle........................................Grasses
2. Stems solid, more or less triangular in cross-section, anthers attached at the base.........................................................................Sedges
1. Flowers not inclosed in husk-like glumes.
3. Aquatic plants, entirely submerged or with some of the leaves floating on the surface.
4. Plant a small floating disc with several roots below, or a minute floating globule.............................................................. Duckweeds
4. Plant not a small floating disc or globule
5. Stems branched and leafy, leaves long and grass-like or ovate.
6. Flowers inconspicuous, axillary or in short spikes..................................................................................................................Najads
6. Flowers star-like, yellow, raised above the surface on slender pedicels.................................................................. Mud-plantains
5. Stems not branched and leafy.
7. Stems mostly simple, leaves short, linear, whorled......................................................................................................Waterweeds
7. Plant more or less stemless, leaves arising from the base.
8. All leaves from the root, long and ribbon-like, flowers on separate thread-like stems.............................................. Tape-grass
8. Leaves basal in an erect tuft, lanceolate, flat or awl-shaped, flowers projecting above the surface.
9. Flowers showy, white, in an open, whorled spike.................................................................................................. Arrowheads
9. Flowers minute, packed together into a compact, button-like head......................................................................... Pipeworts
3. Erect plants, growing in water, swamps or dry ground.
10. Flowers regular, all petals of similar size and shape.
11. Leaves in whorls around the stem, or palmately lobed.
12. Leaves one or two, palmately divided....................................................................................................................................Arums
12. Leaves in whorls around the stem.
13. Leaves in one whorl of three, flowers solitary.................................................................................................................Trilliums
13. Leaves in two or more whorls.
14. Leaves in two whorls of more than three, flowers several................................................................ Indian Cucumber-root
14. Leaves in many whorls, flowers large, red or orange........................................................................................................ Lilies
11. Leaves not whorled or palmately divided.
15. Leaves all radical (emerging from the base, not up the stem).
16. Leaves sagittate (shaped like an arrow head).
17. Flowers white, in an open, whorled spike............................................................................................................ Arrowheads
17. Flowers not white.
18. Flowers blue, in a compact spike................................................................................................................... Pickerelweed
18. Flowers minute, compacted into an upright, cigar-like spike (spadix) incased in a outer spathe............................Arums
16. Leaves not sagittate.
19. Leaves oval or ovate, at least 25 mm. wide.
20. Leaves more than two.
21. Flowers minute, on a fleshy, rounded or cigar-like spadix, with no sepals or petals.
22. Spadix covered by a hood-like spathe, appearing before the large, cabbage-like leaves................... Skunk-cabbage
22. Spadix exposed, bright yellow, leaves usually floating..............................................................................Golden-club
21. Flowers with obvious petals and sepals, mostly showy.
23. Flowers white.
24. Flowers in a much-branched, whorled panicle, each flower relatively small-petalled.................Water-plantains
24. Flowers in a whorled spike, petals relatively large................................................................................Arrowheads
23. Flowers pink, in a dense spike.................................................................................................................. Swamp-pink
20. Leaves only two.
25. Flowers single, lily-like, yellow; leaves spotted.............................................................................................. Trout-lilies
25. Flowers white, clustered in a rounded head, plant garlic scented, leaves absent at flowering time.......American Leek
19. Leaves grass-like or long linear, less than 25 mm. wide.
g. Flowers in a remotely whorled spike or an umbel. Alismacece, p. 168 gg. Flowers in a slender continuous spike. h. Leaves slender, grass-like, erect, flowers minute (spike resembling that of a plantain). Triglochin, p. 166 hh. Leaves lanceolate spatulate, forming a rosette, flowers white, bellshaped, mealy. Aletris, p. 347 ggg. Flowers in a globular compact head. h. Head white, button-like, flowers minute. Eriocaulon, p. 323 hh. Head of imbricated brown scales, flowers protruding, conspicuous, yellow. Xyris, p. 319 gggg. Flowers conspicuous, star-shaped, in an open panicle. h. Flowers white, leaves glabrous. [Ornithogalum umbellatum]* hh. Flowers yellow, leaves hairy. Hypoxis, p. 3SS