Page:An introduction to physiological and systematical botany (1st edition).djvu/332

 302 appendage to Seeds, as in Embothrium, Bot. of N. Holl., t. 7, Banksia, Conchium, Bignonia echinata, Gærtn. t. 52, Rhinanthus, ''Engl. Bot. t.'' 657, serving to waft them along in the air. Gærtner wished to confine this term to a membranous expansion of the top or upper edge of a Seed or Seed-vessel, using margo membranaceus for one that surrounds the whole, but he has not adhered to it in practice. Capsules are sometimes furnished with one wing, as the Ash, oftener with several, as Halesia, Acer, Begonia, &c. In Seeds the Wing is commonly solitary, except some Umbelliferous plants, as Thapsia, Gærtn. t. 21.

Seeds are occasionally furnished with Spines, Hooks, Scales, Crested appendages, particularly a little gland-like part near the Scar, sometimes denominated Strophiolum, as in Asarum, Gærtn. t. 14, Bossiæa, Ventenat. ''Jard. de Cels. t. 7, Platylobium, Bot. of N. Holl. t. 6, Ulex, Spartium'', &c. In general however smoothness is characteristic of a seed, by which it best makes its way into the soft earth,