APOCYNACEAE + Asclepiadaceae (Dogbane/Milkweed Family)

Name: ______Due: Monday, Aug. 10th

APOCYNACEAE + Asclepiadaceae (Dogbane/Milkweed family)

• 355 genera; 3700 species • Herbs (sometimes shrub-like) in PNW • Leaves opposite or alternate - whorled • Flowers bisexual, actinomorphic; 5 ± connate sepals, 5 fused petals (often with corona); 5 short stamens (often modified into pollinia); 2 carpels, stylar head, fused - distinct style, ovaries distict and superior • Fruits paired; follicles, berries, drupes with flattened, comose seeds • Examples: Asclepias (milkweed), Vinca (periwinkle), Apocynum (dogbane)

Medicinal Herb Garden The first area of the garden is called Cascara Circle, the entrance is flanked by monkey statues. Proceed up the trail to the west (note the rosehips to your left & right as you walk by them) to enter Section A. The next section with the shed is Section B. Cross the driveway/road to get to Section C. Section D is across from Anderson Hall and is long and narrow. That will lead you to Section E, which is divided from Section F by a large bed of rosemary.

Section A Review: check out Borago officialis (Boraginaceae) as you walk through this section. Note the thick filaments and surrounding them the fornices projecting from the corolla. Next to it is Spiraea alba (Rosaceae). Look for the hypanthium. It’s especially visible in the unopened flowers, beneath the green sepals...

Section C Asclepias plants contain cardiac glycosides (which increase the force of contraction of the heart by means that are still unclear) and monarch butterflies feed on these plants exclusively. When absorbed by the larvae, the glycosides make the caterpillar and adult butterfly toxic to predators. As you enter this section proceed to the 1st row (act as if rows run from the chemistry bldg towards Steven’s Way, and numbering starts in the NE corner, that is the corner closest to the HUB). Walk about half way towards Steven’s Way, look for Asclepias tuberosa (butterfly milkweed). These plants are in fruit and in flower. You should expect to see paired follicles, but often one aborts. Note the huge follicles and take a look at the flowers. On the back of this or on your own sheet, attempt a detailed sketch of the plant, including fruit and flowers. Label the reflexed corolla lobes, the horn appendage and the hood appendage (3 pts).

In the 3rd row, just a bit closer to Steven’s Way is Asclepias syriaca (common milkweed), which is in fruit. These fruit have large, soft prickles.

Section E At the N end, look for the bloodflower, Asclepias curassavica. Note the different colored corolla and corona appendages. The inflorescence is a cyme such that each flower’s pedicel arises from the same place within each inflorescence.

BIOL 317: Plant Classification & Identification Summer 2009