Annual polemonium (Polemonium micranthum) is an annual native growing in vernally moist to dry disturbed areas, often in association with sagebrush (Artemesia sp). It can be found between approximately 1,000 to 4,500 feet in British Columbia and the Western States as far east as North Dakota, Wyoming and Utah. There are also populations in Pennsylvania and Massachusetts.
A member of the Phlox Family (Polemoniaceae), annual polemonium is a small, taprooted wildflower with a simple, erect stem. The herbage is glandular. The alternate leaves are pinnately compound with 7 to 15 entire leaflets.
Annual polemonium inflorescences are solitary flowers in the upper leaf axils. The flower stalks are short and elongate with age. The calyx is formed by five, pointed lobes that are longer than the petals. The five white petals are united and appear tucked into the calyx. The flower has 5 stamens and a superior ovary with a 3-parted style.
The fruit of annual polemonium is a 3-chambered capsule in the swollen calyx.
P micranthum is also commonly called annual sky pilot and annual Jacob’s ladder. The genus name derives from Polemon of Cappadocia, a Greek herbalist and healer. The species designation means “small flowered”.
These specimens were photographed near the Pilot Butte Parking Area at Ash Creek Wildlife Area near Lookout CA (Modoc County).