Apocynaceae

Apocynaceae – Dogbane Family

The Apocynaceae contains a range of perennial herbs, shrubs, vines and, tropical trees found across Africa, Asia, Australia, Europe, and North America. Many of the Apocynaceae exude a milky latex, which can be quite toxic upon ingestion.[i] In fact, what gives this family its name, Apocynum cannabinum, or the Dog Bane family, means “poisonous to dogs” and causes canine cardiac arrest if ingested.[ii] Many Dog Bane members are fibrous organisms, traded among numerous North American communities to make string for sewing and weaving.[iii] Flowers have sepals and petals in sets of five, as well as a surrounding “corona” that looks like a set of five, hood-shaped structures in the flower’s center. Inside of the corona are five stamens fused to the superiorly positioned ovary.[iv] Ovaries have two separate carpel chambers. Leaves are simple and smooth edged (entire), and can be in an opposite, alternate, or whorled arrangement around the stem.

In Willamette Valley wetlands, the subfamily Asclepiadaceae (Milkweed) is the most commonly occurring member of the Apocynaceae. Asclepiadaceae also produce milky latex (the group’s namesake), have simple, entire leaves in either an opposite or whorled arrangements.[v] Flowers carry out general Apocynaceae patterns. Fruits are dehiscent follicles, containing many small, wind pollinated dry, flat seeds connected to delicate silky hairs.[vi]

Asclepias speciosa – Showy MilkweedAsclepias-speciosaSpecies Code: ASSP

Habit: A stout, branched, pubescent perennial, that is often 1 ½ – 3 feet in height but can also reach up to 6 feet under favorable conditions.[vii]

Leaves:  Large, simple, oval-shaped, blue-green, velvety leaves are oppositely arranged along the stem. Veins are pinnate and thick. Margins entire.[viii]

Flowers: Inflorescences are globular umbels of star-like pinkish flowers borne from plant’s upper axils and bloom May-September. Inflorescences can reach up to 3 inches across and are comprised of fragrant blossoms.

Fruits: Flowers give way to rough seed pods, 2-3″ long, which split open when ripe revealing many silky-tailed seeds for wind dispersal.

Ecology: Facultative Species (FAC),[ix] Occurs on dry slopes, open woodland areas, roadsides, disturbed areas. Survives in wet areas and stream sides across  western North America.[x]

Notes: Important nectar species for hummingbirds and butterflies, a larval host for Monarchs.[xi] The fibers from showy milkweed were used by Native Americans to make ropes, nets and other food items, however, needed to be positively identified as not being other poisonous milkweed varieties.[xii]

Asclepias fascicularisIMG_3630

 

[i] Elpel, T. J., Botany in a Day: The Patterns Method of Plant Identification. HOPS Press, 2004. 121.

[ii] Elpel, T. J., Botany in a Day: The Patterns Method of Plant Identification. HOPS Press, 2004.  121.

[iii] Pojar, J., Mackinnon, A., Editors Plants of the Pacific Northwest Coast. Lone Pine Publishing, Vancouver, Canada. 2004. 320

[iv] Gilkey, H. Handbook of Northwestern Plants, Revised Edition. Oregon State University Press; Corvallis, OR. 2001. 321

[v] Gilkey, H. Handbook of Northwestern Plants, Revised Edition. Oregon State University Press; Corvallis, OR. 2001. 323

[vi] Pell, Susan. A Botanist’s Vocabulary. Timber Press, Portland, OR, 2016. 94.

[vii] Ladybird Johnson Wildflower Center: <https://www.wildflower.org/plants/result.php?id_plant=assp&gt;

[viii] Missouri Botanic Gardens: <http://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?kempercode=b470&gt;

[ix] USDA Plants Database: < https://plants.usda.gov/core/profile?symbol=ASSP&gt;

[x] USDA Plants Database: < https://plants.usda.gov/core/profile?symbol=ASSP&gt;

[xi] Ladybird Johnson Wildflower Center: <https://www.wildflower.org/plants/result.php?id_plant=assp&gt;

[xii] Pojar, J., Mackinnon, A., Editors Plants of the Pacific Northwest Coast. Lone Pine Publishing, Vancouver, Canada. 2004.