The Salicaceae is the willow family of flowering plants. The traditional family (Salicaceae sensu stricto) included the willows, poplar, aspen, and cottonwoods. Genetic studies summarized by the Angiosperm Phylogeny Group (APG) have greatly expanded the circumscription of the family to contain 56 genera and about 1220 species, including the Scyphostegiaceae and many of the former Flacourtiaceae.[3][4][5]
In the Cronquist system, the Salicaceae were assigned to their own order, Salicales, and contained three genera (Salix, Populus, and Chosenia). Recognized to be closely related to the Violaceae and Passifloraceae, the family is placed by the APG in the order Malpighiales.
Under the new circumscription, all members of the family are trees or shrubs that have simple leaves with alternate arrangement and temperate members are usually deciduous. Most members have serrate or dentate leaf margins, and those that have such toothed margins all exhibit salicoid teeth; a salicoid tooth being one in which a vein enters the tooth, expands, and terminates at or near the apex, near which are spherical and glandular protuberances called setae. Members of the family often have flowers which are reduced and inconspicuous, and all have ovaries that are superior or half-inferior with parietal placentation.[6]
Salicaceae is divided into three subfamilies, with Salicoideae further divided into six tribes.[2][7][8]
Salicoideae
Abatieae
Bembicieae
Homalieae
Prockieae
Saliceae
Scolopieae
Samydoideae
Scyphostegioideae
incertae sedis
Illustration of a typical salicoid tooth, the yellow area showing the expanding leaf vein and glandular seta. Populus trichocarpa leaf margin showing a salicoid tooth. The brownish-yellow area in the axil of the tooth is the glandular seta. The Salicaceae is the willow family of flowering plants. The traditional family (Salicaceae sensu stricto) included the willows, poplar, aspen, and cottonwoods. Genetic studies summarized by the Angiosperm Phylogeny Group (APG) have greatly expanded the circumscription of the family to contain 56 genera and about 1220 species, including the Scyphostegiaceae and many of the former Flacourtiaceae.
In the Cronquist system, the Salicaceae were assigned to their own order, Salicales, and contained three genera (Salix, Populus, and Chosenia). Recognized to be closely related to the Violaceae and Passifloraceae, the family is placed by the APG in the order Malpighiales.
Under the new circumscription, all members of the family are trees or shrubs that have simple leaves with alternate arrangement and temperate members are usually deciduous. Most members have serrate or dentate leaf margins, and those that have such toothed margins all exhibit salicoid teeth; a salicoid tooth being one in which a vein enters the tooth, expands, and terminates at or near the apex, near which are spherical and glandular protuberances called setae. Members of the family often have flowers which are reduced and inconspicuous, and all have ovaries that are superior or half-inferior with parietal placentation.
