As she shut the drawer, the envelopes on the top of the desk caught her attention.
Portions of the fructification may be preserved in small envelopes attached to the sheets.
In mathematics, the "caustic surfaces" of a given surface are the envelopes of the normals to the surface, or the loci of its centres of principal curvature.
Still using stamps and envelopes.
By the suppression of the verticil of the stamens, or of the carpels, flowers become unisexual or diclinous, and by the suppression of one or both of the floral envelopes, monochlamydeous and achlamydeous flowers are produced.
