E-Flora BC: Electronic Atlas of the Flora of British Columbia

Asclepias speciosa Torr.
showy milkweed
Apocynaceae (Dogbane family)
(Previously in Asclepiadaceae)

Introduction to Vascular Plants

Distribution of Asclepias speciosa
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Species Information

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Illustration Source: The Illustrated Flora of British Columbia

General:
Perennial herb from a rhizome; stems erect, 0.4-1.2 m tall, woolly, greyish or glabrous below; plants with milky juice.

Leaves:
Opposite, simple, 10-20 cm long, fleshy, oblong or oval, rounded or heart-shaped at the base, stalked.

Flowers:
Inflorescence an umbrella-like cluster; flowers pink to reddish-purple; sepals greenish-tinged with red.

Fruits:
Cylindric pods with soft tubercules, 7-11 cm long, many-seeded with tufts of white cottony hairs; seeds flattened, wrinkled.

Source: The Illustrated Flora of British Columbia

USDA Species Characteristics

Flower Colour:
White

Blooming Period:
Early Summer

Fruit/Seed characteristics:
Colour: Black
Present over the Summer

Source: The USDA

Habitat / Range

Moist to mesic roadsides, ditches, streamsides, meadows and grasslands in the steppe and montane zones; common in SC and SE BC; E to MB and S to MO, TX and CA.

Source: The Illustrated Flora of British Columbia

Ecology

Ecological Framework for Asclepias speciosa

The table below shows the species-specific information calculated from
original data (BEC database) provided by the BC Ministry of Forests and Range.
(Updated August, 2013)

Site Information	Value / Class
Site Information	Minimum	Average	Maximum
Elevation (metres)	296	425	600
Slope Gradient (%)	0	4	34
Aspect (degrees) [0 - N; 90 - E; 180 - S; 270 - W]	200	219	240
Soil Moisture Regime (SMR) [0 - very xeric; 4 - mesic; 8 - hydric]	0	3	6
Modal Nutrient Regime Class	D
Number of field plots species was recorded in:	9
Modal BEC Zone Class	BG
All BEC Zones (# of stations/zone) species was recorded in:	BG(9)
Source: Klinkenberg 2020

Climate

The climate type for this species, as reported in the: "British Columbia plant species codes and selected attributes. Version 6 Database" (Meidinger et al. 2008), is not evaluated, unknown or variable.

Status Information

Origin Status	Provincial Status	BC List (Red Blue List)	COSEWIC
Native	S5	Yellow	Not Listed

BC Ministry of Environment: BC Species and Ecosystems Explorer, the authoritative source for conservation information in British Columbia.

Synonyms and Alternate Names

Asclepias giffordii Eastw.

Taxonomic and Nomenclatural Links

Genetic information (NCBI Taxonomy Database)
International Plant Names Index
Taxonomic Information from the World Flora Online
Integrated Taxonomic Information System

Additional Range and Status Information Links

Burke Museum of Natural History (Washington State records)
CalFlora
Consortium of Pacific Northwest Herbaria records
Jepson Interchange
NatureServe Explorer
USDA

Additional Photo Sources

Images From CalPhoto
UT Austin's Native Plant Database
Google Image Search
Flickr Image Search

General References

Google Scholar Search
Family References
General Botanical References for BC

Recommended citation: Author, Date. Page title. In Klinkenberg, Brian. (Editor) 2020. E-Flora BC: Electronic Atlas of the Plants of British Columbia [eflora.bc.ca]. Lab for Advanced Spatial Analysis, Department of Geography, University of British Columbia, Vancouver. [Accessed: 2024-11-21 7:27:10 AM ]

Disclaimer: The information contained in the E-Flora atlas pages is derived from expert sources as cited in each section. This information is scientifically based. E-Flora also acts as a portal to other sites via deep links. As always, users should refer to the original sources for complete information. E-Flora BC is not responsible for the accuracy or completeness of the original information.