hyalodermis

noun

(pl. hyalodermides, hyaloderms) Differentiated external cells; e.g. thickwalled, enlarged or hyaline cells; stem epidermis of enlarged, hyaline cells, i.e. the chloroplasts are very few or lacking; such cells may be protoplasmic (e.g. Cephalozia) or not (e.g. Sphagnum) at maturity