Geraniaceae – Geranium Family

Geraniaceae – Geranium Family

Regular, bisexual flowers with five sepals, five petals, and usually 10 stamens arranged in whorls.[1] Superior ovaries consist of five united carpels that form a dry schizocarp of the same number of individual chambers. In fact, it is this long seedpod that gives the family its name. As the flower withers, only this needle-like structure is left, giving each fruit bloom the look of a tiny, long-billed stork. Therefore the Latin “geranium” is derived from the Greek word “geranos,” meaning crane, referring to the family’s long, dehiscent seed pods.[2]

With only a few species occurring in Pacific Northwest wetland prairies, Geramium oreganum (Western Geranium), is the single native occurring in the southern Willamette Valley. Over the past decade, invasive Geraniaceae, particularly Shining Geranium (Geranium lucidum),  problematic across western Oregon and Washington.[3] Native to Eurasia, Shining Geranium was used traditionally in Eurasia as an herbal diuretic and astringent, but is considered a problematic invader in Willamette Valley wetland prairies, oak savannah, and riparian woodlands.[4] Tolerant of shade and wet soils, this annual sprouts with the arrival of fall rains and by early spring, these leafy plants create a short canopy outcompeting native wildflowers. By early summer, Shining Geranium releases large quantities of small seed easily transported on boots, pets, wildlife, and vehicles.

Geranium oreganum –  Oregon GeraniumGEORSpecies Code: GEOR

Habit: Perennial forb with erect, hairy, branching stems with visibly swollen nodes. Grows to about 15 to 30 inches in height.

Leaves: Palmate leaves with 5 to 7 deeply lobed segments that are mucronate, or end ever so slightly in a sharp point.[5]

Flowers: Pink to reddish purple solitary flowers are 3.5 to 5 centimeters in diameter, with ciliate margins at the base and slightly hairy sepals. Flowers have ten stamens, a five lobed pistil, and five united styles.[6]

Fruits: Inferior ovary develops a long, five chambered capsule holding 2 seeds in each.[7]

Ecology: Facultative Wetland Species, (FACW), Usually occurs in wetlands but tolerates dry conditions.[8]

 

 

 

 

[1] Simpson, M. Plant Systematics 2nd ed. Academic Press, Burlington, MA. 2010. 349.

[2] Quattrocchi, U. CRC world Dictionary of Plant Names: Common Names, Scientific Names, Eponyms, Synonyms, and Etymology. Boca Raton : CRC Press; 2000

[3] Oregon Department of Agriculture, Noxious Weed Control Program, Salem, OR  <https://www.oregon.gov/ODA/shared/Documents/Publications/Weeds/ShinyGeraniumProfile.pdf&gt;

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

[5] Gilkey, H. Handbook of Northwestern Plants, Revised Edition. Oregon State University Press; Corvallis, OR. 2001. 250

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

[7] City of Eugene, Seed Collection Manual, Geranium oreganum, 2009.

[8] USDA Plants Database: <https://plants.usda.gov/core/profile?symbol=GEOR2&gt;