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Asclepias erosa
DESERT 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.
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 erosa Torr.
NATIVE
Habit: Perennial herb, very hairy to glabrous. Stem: ascending to erect. Leaf: opposite; petiole generally 0; blade elliptic, lanceolate, or ovate, base tapered to cordate, clasping stem or not, margins generally +- wavy and/or +- jagged. Inflorescence: terminal and at nodes; peduncle 2--12 cm. Flower: corolla reflexed to spreading, pale cream or green-white; hoods elevated above corolla base, +- exceeding anther head, generally cream, occasionally yellow or +- red; horns exserted, exceeded by to at +- same level as hoods, converging over anther head or not. Fruit: erect on +- reflexed pedicels. Seed: 10--13 mm. Chromosomes: 2n=22.
Ecology: Dry slopes, washes; Elevation: 150--1900 m. Bioregional Distribution: s SN, SnJV, SW, W&I, D; Distribution Outside California: to Utah, Arizona, Baja California. Flowering Time: Apr--Oct
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 erosa, Revision 1, in Jepson Flora Project (eds.) Jepson eFlora, http://ucjeps.berkeley.edu/cgi-bin/get_IJM.pl?tid=14371, accessed on May 03, 2016.

Citation for the whole project: Jepson Flora Project (eds.) 2016. Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html, accessed on May 03, 2016.


Asclepias erosa
click for enlargement
© 2012 Neal Kramer
Asclepias erosa
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© 2014 Keir Morse
Asclepias erosa
click for enlargement
© 2014 Keir Morse
Asclepias erosa
click for enlargement
© 2014 Keir Morse
Asclepias erosa
click for enlargement
© 2014 Keir Morse
Asclepias erosa
click for enlargement
© 2011 Neal Kramer

More photos of Asclepias erosa in CalPhotos


Geographic subdivisions for Asclepias erosa:
s SN, SnJV, SW, W&I, D;
Markers link to CCH specimen records. If the markers are obscured, reload the page [or change window size and reload]. Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues.
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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).

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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.