ESSEX   BOTANY   AND   MYCOLOGY  GROUPS 

Prior to the detailed studies of Proskauer in the 1950s the taxonomy of the European hornworts was very confused, and British material was misnamed. Symers MacVicar had three species A. husnotii Steph., A. punctatus L. and A. crispulus (Mont.) Douin in his Student's Handbook of Hepatics. The first two are now regarded as synonymous, the amalgamation taking the name A. punctatus L. A. crispulus however is now known not be a European taxon, although it occurs in Asia and N. America, and what was formerly mistakenly called A. crispulus over here is now called A. agrestis Paton. It is generally a smaller more frilly species,  than A. punctatus with radiating lamellae on the surface and smaller sporophytes, but the only reliable way of separating them is via the size of their antheridia. In Essex the only taxon authenticated so far is A. agrestis. Unlike the now separated genus Phaeoceros, Anthoceros has numerous cavities [lacunae] that are initially mucilage filled and in places open ventrally via pores. These frequently contain Nostoc cyanobacterial colonies. In addition the spores of Phaeoceros are yellow and finely papillose whereas those of Anthoceros are black and spinose.