Salicaceae

alt=The image shows a drawing of a small portion of the edge of a leaf bearing a salicoid tooth. Black veins cross the leaf surface, but one vein is marked yellow and widens as it approaches the tooth. At the tip of the tooth is a semicircular protuberance, also drawn as yellow for emphasis.|thumb|Illustration of a typical salicoid tooth, the yellow area showing the expanding leaf vein and glandular seta. alt=The image is a photograph of the edge of the underside of a leaf. The leaf takes up the upper two-thirds of the image and the leaf margin runs right to left, with a single tooth jutting out bluntly to the left. Also sporadically along the edge of the leaf are small, transparent hairs. The light-colored leaf surface is intersected with dark veins, one of which comes in from the top right of the image towards the tooth, and it widens abruptly as it nears the tooth. Between the tip of the tooth and where it steps down to the next part of the leaf margin is a shallow bulge with a brownish hue, a distinctly different color from the rest of the leaf. A red scale bar at upper left, occupying about a quarter of the width of the image, above which reads "0.5 mm."|thumb|Populus trichocarpa leaf margin showing a salicoid tooth. The brownish-yellow area in the axil of the tooth is the glandular seta.

The Salicaceae are the willow family of flowering plants. The traditional family (Salicaceae sensu stricto) includes the willows and poplars. 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 tropical Scyphostegiaceae and many of the former Flacourtiaceae.