7. Vancouveria C. Morren & Decaisne, 2: 351. 1834.
Inside-out flower [for George Vancouver (1757-1798), English navigator and explorer]
David Whetstone, Daniel D. Spaulding & T.A. Atkinson
Herbs, perennial, evergreen or deciduous, 1-5 dm, glabrous, glandular-pubescent, or sparsely hairy. Rhizomes extensive, creeping, nodose, producing 3 or more foliage leaves and flowering shoots per year. Aerial stems absent. Leaves basal, alternate, 2-3-ternately compound (sometimes 3-5-foliolate in V . chrysantha ); petiole long, slender. Leaf blade deltate in overall outline; rachis without pulvinae; leaflet blades rhomboid or rounded pentagonal to ovate to oblong, shallowly 3-lobed, margins entire to sinuate; venation palmate. Inflorescences terminal, racemes or panicles, open. Flowers 3-merous, 6-14 mm; bracteoles 6-9, sepaloid; sepals 6, white to yellow; petals 6, white to yellow, hooded with tip reflexed or flat, bearing nectar; stamens 6; anthers dehiscing by 2 apically hinged flaps; pollen exine striate; ovaries ellipsoid; placentation marginal; style lateral. Fruits follicles, brown, asymmetric, generally elliptic, dehiscing by 2 valves. Seeds 4-7, black to reddish brown; aril whitish, covering ca. 1/2-2/3 of seed. x = 6.
Species 3 (3 in the flora): w United States.
The fruits of Vancouveria are thin-walled follicles that are green or greenish brown at the time of dehiscence. The follicles dehisce by means of two valves that begin below the style and open to the base. The two valves recurve, exposing the seeds downward. In V . hexandra the follicle opens before the seeds are mature. The green seeds continue to grow and ripen in the open follicle. The appendage or aril on Vancouveria seeds has been shown to be a true elaiosome (R. Y. Berg 1972). Ants carry the seeds to their nests and harvest the appendage as a food source.
SELECTED REFERENCES
Berg, R. Y. 1972. Dispersal ecology of Vancouveria (Berberidaceae). Amer. J. Bot. 59: 109-122. Stearn, W. T. 1938. Epimedium and Vancouveria, a monograph. J. Linn. Soc., Bot. 51: 409-535.
