Fig. 160. Plocaria helminthocorton.

a. The plant (natural size).
b. A small stony coral attached to the thallus, and which may be readily mistaken for the fructification.
c. The same, broken and magnified to show the pores.

This image is from Corsican Moss in Pereira's Elements of Materia Medica and Therapeutics, 1854.