Aristolochia watsonii

Classification System: APG IV

Superregnum: Eukaryota
Regnum: Plantae
Cladus: Angiosperms
Cladus: Magnoliids
Ordo: Piperales

Familia: Aristolochiaceae
Subfamilia: Aristolochioideae
Genus: Aristolochia
Species: Aristolochia watsonii
Name

Aristolochia watsonii Wooton & Standl.
References

USDA, NRCS. 2006. The PLANTS Database, 6 March 2006 (http://plants.usda.gov). Data compiled from various sources by Mark W. Skinner. National Plant Data Center, Baton Rouge, LA 70874-4490 USA.

Vernacular names
English: Watson's dutchman's pipe

Aristolochia watsonii (Watson's Dutchman's pipe, southwestern pipevine, Indian root, snakeroot) is a perennial plant[2] in the birthwort family (Aristolochiaceae), found growing among plants of the Arizona Uplands in the Sonoran Desert.[3]: 138  The plant is inconspicuous,[3]: 138  small and hard to spot, but can be found by following the pipevine swallowtail (blue swallowtail, Battus philenor) which lays eggs on it.[2]

Description
Growth pattern

It grows as vine with scrambling stems that create a dense, tangled mat over the years when growing on open ground.[2][3]: 138 
Roots, stems, and leaves

According to one source, stems are 150 to 450 mm (6 to 18 in) long, with greenish-brown arrowhead-shaped 5 to 65 mm (1⁄4 to 2+1⁄2 in) leaves.[3]: 138  Another source states stems can reach 0.9 m (3 ft), in dense mats that are 0.3 to 0.6 m (1 to 2 ft) wide.[2] It drops its leaves in the fall and winter (cold-deciduous), and loses stems as well as leaves in a freeze.[2] In full sun and drought conditions, leaves turn from green to purple-brown.[2]
Inflorescence and fruit

It has "bizarre" looking, musky-smelling flowers, which resemble the ear of a rodent.[3]: 138  It blooms from April to October. 25 to 40 mm (1 to 1+1⁄2 in) flowers are shaped like a rodent's ear[2][3]: 138  are green or burgundy-brown outside to the ear rim, then green speckled with burgundy-brown inside, with hairs on the opening ear rim.[3]: 138  Flowers last 1–2 days.[2]

Fruits are capsules having five vertical ribs with triangular-shaped flat and black seeds in each of five compartments.[2]
Ecological interactions

Flowers shaped and smelling like a rodent's ear attract small blood-sucking flies, which are deceived by the appearance and odor and get trapped in the convoluted flower form for a day, then escape to pollinate another plant.[2][3]: 138  It attracts the pipevine swallowtail,[4] and is where the butterfly gets its distasteful toxins that protect the butterfly from predation.[2] The caterpillar may eat all of the leaves on a plant, but they then grow back.[2]
Toxicity

All parts of this plant are toxic to humans.[2][5]
Habitat and Distribution

It is found from Arizona to western Texas, in mountains at elevations from 600 to 1,400 m (2,000 to 4,500 ft).[3]: 138 
Human use

Native Americans believed it could be used to treat snakebites, hence its common names Indian root or snakeroot.[3]: 138  It is currently found in some nurseries that feature native plants as it is a good landscape plant in a butterfly garden.[6]
References

"Aristolochia watsonii Wooton & Standl.". World Checklist of Selected Plant Families (WCSP). Royal Botanic Gardens, Kew. Retrieved 28 August 2014 – via The Plant List.
Aristolochia watsonii: Watson's Dutchman's Pipe / Desert Pipevine, Garden Oracle, Gardening in Tucson, Phoenix, and the Desert Southwest, [1] Archived 2014-09-03 at the Wayback Machine
Sonoran Desert Wildflowers, Richard Spellenberg, 2nd ed., 2012, ISBN 9780762773688
Naturewide Images, Robert A. Behrstock, ATTRACTING WILDLIFE I
"Pipevine Swallowtail, Battus philenor, Fairfax County Public Schools". Archived from the original on 2014-06-23. Retrieved 2014-08-28.
Soule, J.A. 2011. Butterfly Gardening in Southern Arizona. Tierra del Sol Press.