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Key to families | Table of families and genera

Specimen numbers are hyperlinked to records in the Consortium of California Herbaria data view where possible. Taxa are hyperlinked to entries in the Jepson Interchange via the "[Online Interchange]" link.



Thomas J. Rosatti, except as noted

Annual, perennial herb, shrub, tree, often vine; sap generally milky. Leaf: simple, alternate, opposite, subwhorled to whorled, entire; stipules 0 or small, finger-like. Inflorescence: axillary or terminal, cyme, generally umbel- or raceme-like, or flowers 1–2. Flower: bisexual, radial; perianth parts, especially petals, overlapped, twisted to right or left, at least in bud; sepals generally 5, fused at base, often reflexed, persistent; petals generally 5, fused in basal ± 1/2; stamens generally 5, attached to corolla tube or throat, alternate lobes, free or fused to form filament column and anther head, filament column then generally with 5 free or fused, ± elaborate appendages abaxially, pollen ± free or removed in pairs of pollinia; nectaries 0 or near ovaries, then 2 or 5[10], or in stigmatic chambers; ovaries 2, superior or ± so, free [fused]; style tips, stigmas generally fused into massive pistil head. Fruit: 1–2 follicles, (capsule), [berry, drupe]. Seed: many, often with tuft of hairs at 1 or both ends.
200–450 genera, 3000–5000 species: all continents, especially tropics, subtropical South America, southern Africa; many ornamental (including Asclepias, Hoya, Nerium, Plumeria, Stapelia); cardiac glycosides, produced by some members formerly treated in Asclepiadaceae, used as arrow poisons, in medicine to control heart function, and by various insects for defense. [Fishbein 2001 Ann Missouri Bot Gard 88:603–623] Asclepiadaceae ("asclepiads"), although monophyletic, included in Apocynaceae because otherwise the latter is paraphyletic. Complexity of floral structure, variation in asclepiads arguably greatest among all angiosperms. Pattern of carpel fusion (carpels free in ovule-bearing region, fused above), present ± throughout Apocynaceae (in broad sense), nearly unknown in other angiosperms. Base chromosome number generally 11; abundance of latex, generally small size of chromosomes evidently have impeded cytological investigations. —Scientific Editor: Bruce G. Baldwin.
Unabridged references: [Civeyrel et al. 1998 Molec Phylogen Evol 9:517–527; Rosatti 1989 J Arnold Arbor 70:307–401]

Key to Apocynaceae

1. Filaments fused into filament column, generally with 5 free or fused, ± elaborate appendages abaxially; anthers fused into anther head around and fused to pistil head; pollen removed in pairs of pollinia; nectaries in stigmatic chambers (genera formerly treated as Asclepiadaceae)

2. Filament column ± without appendages ..... Funastrum utahense

2' Filament column with appendages

3. Filament column appendages fused into 5-lobed, cup- or plate-like structure around anther head ..... MATELEA

3' Filament column appendages free

4. Filament column appendages hollow (possibly due to complete fusion of margins); ring of tissue at base of corolla present ..... FUNASTRUM

4' Filament column appendages solid (margins converging, nearly meeting or not, not fused); ring of tissue at base of corolla 0

5. Filament column appendage margins converging but not nearly meeting abaxially; flowers in raceme- or panicle-like cymes; stem twining ..... ARAUJIA

5' Filament column appendage margins converging and meeting or nearly meeting adaxially (to form hood); flowers in umbel-like cymes; stem prostrate to erect ..... ASCLEPIAS

1' Filaments free, unappendaged; anthers free, lying against, adherent to pistil head or not; pollen ± free, not removed in pollinia; nectaries 0 or near ovaries (genera formerly treated as Apocynaceae)

6. Seed glabrous; stamens attached near top of corolla tube, near level of stigma

7. Leaves alternate to subwhorled; plant erect ..... AMSONIA

7' Leaves opposite to subopposite; plant erect or sprawling

8. Corolla pink, tube ± cylindric; plant erect ..... [Catharanthus roseus]

8' Corolla purple-blue (white), tube funnel-shaped; plant sprawling ..... VINCA

6' Seed with tuft of long hairs at 1 end; stamens attached at or near base of corolla tube, below level of stigma, or appearing so

9. Plant shrub, small tree; leaves generally whorled or subwhorled (opposite); nectaries 0; sap not milky ..... NERIUM

9' Plant perennial herb; leaves opposite; nectaries 5, free or fused; sap milky

10. Leaves, stems, roots not fleshy; flower < 8 mm, in generally >> 6-flowered cyme; nectaries 5, free ..... APOCYNUM

10' Leaves, stems, roots fleshy; flower > 15 mm, in 2–6-flowered cyme; nectaries 5, fused into a 5-lobed disk ..... CYCLADENIA


Citation for the whole project: Jepson Flora Project (eds.) [year] Jepson eFlora, [accessed on month, day, year]
Citation for an individual treatment: [Author of taxon treatment] [year]. [Taxon name] in Jepson Flora Project (eds.) Jepson eFlora, [URL for treatment]. Accessed on [month, day, year].
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