Spicules cylindrical, equal in size and shape, tapering distally, tips sharp; more rarely compressed, flexible. Leaf-cross 2-3 times broader than spicules. Sometimes spicules of equal width throughout length, leaf-cross up to 4-6 times broader than spicules. In some specimens 2 opposing equatorial spicules 1.5 times longer than others, yet shape and width similar to that of other 18 spicules. Sometimes pyramidal bases of spicules very long, almost reaching central capsule, 4-edged within central capsule; thin, needle-like outside. Spicule length: 0.3-0.4 mm, length of basal pyramids: 0.024-0.03 mm.
Two subspecies: Phyllostaurus siculus catervatus Schewiakoff, 1926, and Phyllostaurus siculus quadrifolius Schewiakoff, 1926.