Vancouveria
Ann. Sci. Nat., Bot., sér. 2, 2: 351. 1834.
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.
Distribution
w United States
Discussion
Species 3 (3 in the flora).
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 elaiosome (R. Y. Berg 1972). Ants carry the seeds to their nests and harvest the appendage as a food source.
Selected References
Key
| 1 | Leaflet margins not conspicuously thickened; leaves falling when fruits maturing; pedicels lacking glands. | Vancouveria hexandra |
| 1 | Leaflet margins conspicuously thickened; leaves persistent; pedicels stipitate-glandular. | > 2 |
| 2 | Petals yellow, petal apex reflexed; follicles densely stipitate-glandular. | Vancouveria chrysantha |
| 2 | Petals white, sometimes lavender-tinged, petal apex not reflexed; follicles lacking glands. | Vancouveria planipetala |