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Asclepias speciosa

Higher Taxonomy
Family: ApocynaceaeView DescriptionDichotomous Key

Habit: 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.
Genera In Family: 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. Note: 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.
eFlora Treatment Author: Thomas J. Rosatti, except as noted
Scientific Editor: Bruce G. Baldwin.
Genus: AsclepiasView DescriptionDichotomous Key

Common Name: MILKWEED
Habit: Annual, perennial herb, shrub. Stem: prostrate to erect. Leaf: generally opposite (alternate, whorled), each pair at right angles to those below, above, generally persistent; blade narrow-linear to ovate or cordate. Inflorescence: terminal or at generally upper nodes, umbel-like cyme. Flower: ring of tissue at base of corolla 0; filament column appendages (hoods) free, elevated above corolla base or not, each often with an elongate projection (horn) attached to inside, margins converging and meeting or nearly meeting adaxially but not fused; anthers fused into anther head around and fused to pistil head, pollen in pollinia; pistil head flat or conic on top; nectaries in stigmatic chambers. Fruit: erect (but generally on pendent pedicel) or pendent, lance-ovoid to ovoid, smooth or with tubercles.
Species In Genus: In narrow sense of genus, 100 species: North America, Central America, perhaps South America. Etymology: (Greek physician Aesculapius) Note: Fresh flowers generally better for determining relative positions of parts; hoods may have near anther head 2 +- sickle shaped lobes each that may +- resemble horns. A. linaria not outside cultivation in California, so deleted here; previous inclusion in TJM2 (2012) based on faulty locality data.
eFlora Treatment Author: Thomas J. Rosatti & Carol A. Hoffman

Asclepias speciosa Torr.
Habit: Perennial herb, hairy. Stem: ascending to erect. Leaf: opposite; petiole short; blade elliptic to ovate, base rarely cordate, clasping stem. Inflorescence: terminal and at nodes; peduncle 1--10 cm. Flower: corolla reflexed, rose-purple; hoods not to +- elevated above corolla base, much exceeding anther head, pink aging yellow; horns exserted, much exceeded by hoods, at +- same level as anther head. Fruit: +- erect on generally +- reflexed pedicels. Seed: 6--9 mm. Chromosomes: 2n=22.
Ecology: Many habitats including fields, roadsides; Elevation: < 1900 m. Bioregional Distribution: CA (exc possibly CW, SW, DSon, elsewhere); Distribution Outside California: to western Canada, Texas. Flowering Time: May--Sep
Synonyms: Asclepias giffordii Eastw.
Unabridged Note: Although indicated for California in TJM(1993), numerous cos. (especially in CW, SW, DSon) not represented in Consortium database.
eFlora Treatment Author: Thomas J. Rosatti & Carol A. Hoffman
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Citation for this treatment: Thomas J. Rosatti & Carol A. Hoffman 2016. Asclepias speciosa, Revision 1, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on October 28, 2016.

Citation for the whole project: Jepson Flora Project (eds.) 2016. Jepson eFlora,, accessed on October 28, 2016.

Asclepias speciosa
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© 2008 Keir Morse
Asclepias speciosa
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© 2008 Keir Morse
Asclepias speciosa
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© 2008 Keir Morse
Asclepias speciosa
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© 2004 George W. Hartwell
Asclepias speciosa
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© 2009 Keir Morse
Asclepias speciosa
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© 2015 Barry Breckling

More photos of Asclepias speciosa in CalPhotos

Geographic subdivisions for Asclepias speciosa:
CA (exc possibly CW, SW, DSon, elsewhere);
Markers link to CCH specimen records. Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues. Purple markers indicate specimens collected from a garden, greenhouse, or other non-wild location.
map of distribution 1
(Note: any qualifiers in the taxon distribution description, such as 'northern', 'southern', 'adjacent' etc., are not reflected in the map above, and in some cases indication of a taxon in a subdivision is based on a single collection or author-verified occurence).

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Data provided by the participants of the Consortium of California Herbaria.
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CCH collections by month

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa.
Blue line denotes eFlora flowering time.