Porokeratosis (PK) is a clonal disorder of keratinization that is histologically characterized by the presence of a cornoid lamella.

摘要PK是一群角化异常疾病，病理下特徵是可见所谓角样板。

All the seagrasses have horizontal rhizomes, and many species have vertical rhizomes.In some seagrass species, clonal reproduction, via apomict, was also observed.

所有海草都具有水平根状茎，许多海草也具有垂直根状茎，在一些海草中，也无性生殖(无融合生殖)。