Herbs, including partial parasites with some chlorophyll (hemiparasites) and total parasites lacking chlorophyll (holoparasites), attaching to the roots of host plants by many small haustoria or a single large haustorium. Leaves alternate, opposite, or rarely whorled, simple to variously pinnately dissected so as to appear compound, sometimes reduced to scales; stipules absent. Flowers bisexual, zygomorphic or sometimes asymmetric; often associated with conspicuous, sometimes colorful bracts. The perianth is biseriate, with a usually 5-lobed synsepalous calyx and a usually 2-lipped corolla with two lobes (sometimes completely fused and galeate) comprising the upper lip and three lobes comprising the lower lip. The androecium consists of 4 didynamous stamens adnate to the corolla (perigynous zone); a fifth stamen sometimes is represented by a staminode. The gynoecium consists of a single compound pistil of 2 carpels; ovary superior ovary with 1 or 2 locules, each bearing numerous parietal to axile ovules; style single, undivided, bearing a terminal, 2-lobed stigma. A nectar disk is usually present around the base of the ovary. The fruit is a septicidal to loculicidal capsule.
Each "thumbnail" image below is linked to a larger photograph.
||Boschniakia strobilacea, California ground-cone, S OR, April, 2004.|
|Conopholis americana, squaw-root. This species lacks chlorophyll and is totally parasitic on the roots of other kinds of plants.|
|Orobanche sp., broom-rape. Pyrenees.|
|Orobanche sp., broom-rape. This species is totally parasitic on the roots of other plants, primarily in the Asteraceae.|
|Castilleja miniata, common paintbrush. Enlarged and sometimes brightly colored bracts seen here and in some other members of the family can sometimes make the flowers pale by comparison. In this case the calyx is also brightly colored but the corolla is mostly greenish. This is an example of one of the partial root parasites (hemiparasites) in the subfamily Rhinanthoideae (see also Pedicularis).|
||Castilleja attenuata, valley tassels. One of the annual members of the genus.|
||Pedicularis groenlandica, lousewort. The floral morphology in this species is remarkably similar to an elephant's head and is related to a rather specific pollination system that varies widely among species in the genus. Many very different corolla configurations have evolved to exploit a wide range of pollinators, including bees of various types, sphingid moths, and even humming birds. A collection of photographs of many other species can be view by clicking on Pedicularis.|
|Rhinanthus major. Hemiparasite, Aussois, France.|
||Parentucellia viscosa. 1 - vic. Corvallis, OR, 2002. Hemiparasite.|
|Orthocarpus imbricatus, mountain owl clover, representing an annual hemiparasitic genus.|
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