Jepson eFlora

Contact: Comments on these keys should be sent to Tom Rosatti, Scientific Editor (

Citation for the whole project: Jepson Flora Project (eds.) . Jepson eFlora, [accessed on ]


Key to California Plant Families

David J. Keil, as revised by Alan R. Smith and Thomas J. Rosatti to include Cyatheaceae

Only vascular plants are treated in The Jepson eFlora. Vascular plants are a monophyletic group or clade that includes (1) Lycophytes (often superficially moss-like but with thicker scale-like leaves and axillary sporangia that are often borne in cones), (2) Ferns (most with sporangia borne on abaxial leaf surfaces, a few with sporangia on modified leaf segments or in hard sporangium cases), and Equisetum, with whorled scale leaves and sporangia grouped in terminal cones, (3) Gymnosperms (with seeds generally produced in cones of various forms), and (4) flowering plants (with seeds developing in ovaries of flowers). Flowering plants in California include five clades: Nymphaeales, Magnoliids, Ceratophyllales, Eudicots, and Monocots (see back inside cover). Unlike all other organisms, vascular plants have true roots, stems, and leaves, with water- and nutrient-conducting (vascular) tissues that also provide structural support.

In terrestrial (and aquatic) environments, true mosses and leafy liverworts may appear superficially similar to vascular plants, but their minute leaves are filmy (generally only 1 cell layer in thickness), and their delicate, usually short stems are attached to soil or other substrate by fragile filaments of 1 or more cells (rhizoids) that lack conducting tissue. Mosses, the most diverse land plants in California other than vascular plants, have alternate, closely overlapping, scale-like or narrowly linear leaves and produce solitary sporangia (generally finely stalked) at the tips of leafy shoots. Some freshwater liverworts can be confused with free-floating vascular plants that lack clearly differentiated stems and leaves, but the liverworts can be recognized by their forking body plan or forked grooves on their upper surface.

Although in aquatic environments an emergent habit distinguishes vascular plants from other aquatics, potential for confusion of vascular plants with organisms other than mosses and liverworts in fully submersed settings warrants attention. In particular, some marine algae, such as kelps and rockweeds, appear superficially similar to vascular plants because of leaf-like, stem-like, and root-like (holdfast) structures. These algae, however, have accessory pigments ranging in color from olive-green to reddish or brownish that distinguish them from marine vascular plants, which are grass-green in color. Some of these algae have gas-filled floats, which are not found in marine vascular plants, and all of them are somewhat rubbery in texture, in contrast to the papery texture of marine vascular plants. Green alga e are similar in color to vascular plants; of these, charophytes, with a central axis and whorled, cylindric branches (but no leaves) are most readily confused with vascular plants.

Keys in the Jepson eFlora, are based primarily on structures associated with sexual reproduction (e.g., sporangia, cones, flowers, fruits). The eFlora does not provide a means for keying terrestrial vascular plants that are in strictly vegetative condition. For aquatic vascular plants, some of which reproduce mostly by vegetative means, a key is provided that allows identification using only vegetative characteristics. A key is also provided for identification of the few species in which tiny bulblets (small bulbs or corms) take the places of flowers in modified inflorescences or inflorescence-like clusters.

— Scientific Editor: Bruce G. Baldwin

Key To Groups

1. Specimens available for examination without flowers, these either not present on the specimen or not produced at all

2. Bulblets [small  or corms that are dispersed in place of seeds or fruits] formed in place of flowers in inflorescence or inflorescence-like cluster ..... Group 1

2' Bulblets 0

3. Sporangia cases, seedscones, or cone-like structures 0 or not readily apparent [plants in strictly vegetative condition]

4. Plant aquatic ..... Group 2

4' Plant terrestrial [Note: terrestrial plants in strictly vegetative condition cannot be identified with this key]

3' Sporangia cases, seedscones, or cone-like structures present

5. Herbs reproducing by spores released directly from sporangia, the sporangia variously located [on abaxial  face, in stalked cluster arising from  or  base, in hardened case at petiole base, in axils of  or scale-like leaves, or in terminal cone-like structure], seeds and pollen never formed [LYCOPHYTES and FERNS] ..... Group 3

5' Herbs to trees reproducing by seeds

6. Ovules exposed to air at time of pollination, not enclosed in ovarypollen grains deposited directly on ovulestigma 0; seeds, if present, borne between scales of cone or naked on branches, fruit not produced; shrubs or trees [GYMNOSPERMS] ..... Group 4

6' Ovules enclosed in ovaries that on available specimens have matured as  or  fruitsseeds enclosed within ripened pericarp of fruit [if dry remains of flowers are present it may be possible to determine the family of a fruiting specimen under 1' in this key, but not all fruiting specimens may be identifiable here]

1' Specimens available for examination with flowers, often also producing seeds within fruits [ANGIOSPERMS]

7. Specimens with only cleistogamous flowers — fruits developing without flowers opening ..... Group 5

7' Specimens with open flowers

8. Specimens with unisexual flowers of only 1 kind [staminate or pistillate, but not both]; plants dioecious or monoecious

9. Specimen with only staminate flowers

10. Herb or subshrubwoody only at base ..... Group 6

10' Tree or shrub, conspicuously woody ..... Group 7

9' Specimen with only pistillate flowers

11. Herb or subshrubwoody only at base ..... Group 8

11' Tree or shrub, conspicuously woody ..... Group 9

8' Specimens with  flowers or with both staminate and pistillate flowers [on same or different individuals]; plants bisexual, dioecious, or monoecious (occasionally with mixture of bisexual and unisexual flowers)

12. Pistils 2 or more per flower [carpels > 1, free to the base] ..... Group 10

12' Pistil 1 per flower [carpel 1 or carpels > 1 fused at least proximally]

13. Perianth 0 or in a single whorl [appearing to be either sepals or petals but not both], sometimes reduced to scale-like or bristle-like structures

14. Tree or shrub, conspicuously woody

15. Inflorescence, at least the staminate, a  or catkin-like ; flowers unisexual ..... Group 11

15' Inflorescence various but not catkin-like; flowers  or unisexual ..... Group 12

14' Herb or subshrubwoody proximally if at all

16. Leaf venation parallel or leaves and stem not differentiated ..... Group 13

16' Leaf venation generally  or  (sometimes only midvein evident) or leaves reduced to bladeless scales

17. Ovary inferior ..... Group 14

17' Ovary superior ..... Group 15

13' Perianth in 2 or more whorls (generally both sepals and petals) or perianth parts spiraled 2 or more times around floral axis

18. Perianth parts 2 or 3 per whorl ..... Group 16

18' Perianth parts generally 4 or 5 per whorl (rarely some other number or whorls differing in number of parts) or in a spiral with the number of parts indefinite

19. Petals fused into a ring or a tube, the corolla generally falling as a unit [corolla of free petals fused to a  should be keyed under 19']

20. Ovary inferior or partly so ..... Group 17

20' Ovary superior

21. Corolla  ..... Group 18

21' Corolla  ..... Group 19

19' Petals free, at least at base, attached and generally falling singly (sometimes individually joined to a ; in a few families ± joined and falling in groups, but not forming a ring or a tube, or petal 1)

22. Leaf compound or so deeply divided as to appear compound ..... Group 20

22' Leaf , sometimes much reduced

23. Ovary inferior or partly so ..... Group 21

23' Ovary superior

24. Stamens > 2 × as many as petals ..... Group 22

24' Stamens <= 2 × as many as petals

25. Tree or shrub, conspicuously woody ..... Group 23

25' Herb or subshrubwoody only at base ..... Group 24