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Vascular Plants of California
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Asclepias speciosa
SHOWY MILKWEED


Higher Taxonomy
Family: ApocynaceaeView DescriptionDichotomous Key
Common Name: DOGBANE FAMILY
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.
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
Unabridged Reference: Liede-Schumann & Meve 2006 http://www.uni-bayreuth.de/departments/planta2/research/databases/delta_as/www/asclep.htm; Woodson 1954 Ann Missouri Bot Gard 41:1--211
Asclepias speciosa Torr.
NATIVE
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.
Jepson eFlora Author: Thomas J. Rosatti & Carol A. Hoffman
Index of California Plant Names (ICPN; linked via the Jepson Online Interchange)

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Citation for this treatment: Thomas J. Rosatti & Carol A. Hoffman 2013, Asclepias speciosa, in Jepson Flora Project (eds.) Jepson eFlora, Revision 1, https://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=14422, accessed on April 19, 2024.

Citation for the whole project: Jepson Flora Project (eds.) 2024, Jepson eFlora, https://ucjeps.berkeley.edu/eflora/, accessed on April 19, 2024.

Asclepias speciosa
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©2009 Keir Morse
Asclepias speciosa
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©2008 Steve Matson
Asclepias speciosa
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©2009 Neal Kramer
Asclepias speciosa
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©2016 James Morefield
Asclepias speciosa
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©2013 California Academy of Sciences

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Geographic subdivisions for Asclepias speciosa:
CA (exc possibly CW, SW, DSon, elsewhere)
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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).





 

Data provided by the participants of the  Consortium of California Herbaria.
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Blue markers indicate specimens that map to one of the expected Jepson geographic subdivisions (see left map). Purple markers indicate specimens collected from a garden, greenhouse, or other non-wild location.
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CCH collections by month

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa, if there are more than 1 infraspecific taxon in CA.
Blue line denotes eFlora flowering time (fruiting time in some monocot genera).