Synura petersenii f. columnata Siver

(Fig. 4H)

DISTRIBUTION. — United States (Siver 1988).

REMARKS

Differs from the other taxa of Synura petersenii -complex in that the inner portion of the rim is ornamented with row of posts (in SEM) or dots (in TEM) (Siver 1988; Škaloud et al. 2012). Škaloud et al. (2012) believe that this forma does not belong to S. petersenii sensu stricto but it is premature to raise this forma to the rank of species.