Fibres growing from the surface of seeds or from the inner surfaces of fruit cases or pods. Such fibre (seed hairs) are formed by the marked elongation of epidermal cells.
Note : From a botanical aspect, cotton is a seed hair, since it is an outgrowth in the form of single cells from the epidermis or outer skin of cotton seeds. In this respect, cotton differs from fine vegetable fibres, which are composed of a number of plant cells, usually joined and cemented together to form a bundle and often occurring in the stems (e.g., flax) or leaves (e.g., sisal) of plants or shrubs. Nevertheless, in commerce and industry, it is customary to refer to cotton as vegetable fibre. Calotropis (akund) and Asclepias (milkweed) are other examples of hair growing on seeds, whereas Eriodendron (Java kapok) grows on the inner surface and the placenta of seed pods.
Textile Resource (http://www.textile.org.uk)
