Same entry in the Synagoge, Photius (mu519 Theodoridis), and the Lexica Segueriana; in Hesychius mu1620 the glossing is "single-skinned, single-tuniced".
The term is used in the cited neuter plural by Basil of Caesarea, Homilies on the Hexameron 5.7, referring to kinds of bark. (This application is anticipated by Theophrastus, Enquiry into Plants 1.5.2, who uses the word in the same context, but in the masculine singular.)