2. Arceuthobium Marschall von Bieberstein, Fl. Taur.-Caucas. 3: 629. 1819-1820.
[nom. cons.]
油杉寄生属 you shan ji sheng shu
Razoumofskya Hoffmann, nom. rej.
Subshrubs or herbs parasitic on gymnosperms, dioecious. Branches dichotomous or verticillate; stem internodes terete. Leaves reduced to scales, decussate, in 4 ranks, connate. Flowers axillary or terminal on branchlets, decussate or whorled; peduncle absent; pedicel short to nearly absent. Male flower subglobose or ovoid in mature bud; perianth lobes 3 or 4, ± rotate. Anthers sessile, inserted on perianth lobes, circular, 1-loculed, dehiscence transverse; central nectary present. Pollen grains subprolate, 3-lobed to circular in polar section. Female flower ovoid to ellipsoid in mature bud, epigynous; perianth tube short, 2-lobed, adnate to ovary, persistent. Placentation free, central. Style short; stigma obtuse. Berry ovoid or ellipsoid, apex different in texture from base, exocarp smooth, explosively dehiscent at maturity.
About 45 species: temperate and tropical regions of NE Africa, Asia, S Europe, and North America; five species (three endemic) in China.
All members of this genus induce “witches’ brooms,” which cause their hosts to suffer retarded growth and eventually die.
