Anthoceros is a genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of hornwort

Hornwort

Hornworts are a group of bryophytes, or non-vascular plants, comprising the division Anthocerotophyta. The common name refers to the elongated horn-like structure, which is the sporophyte. The flattened, green plant body of a hornwort is the gametophyte plant.Hornworts may be found worldwide,...

s in the family

Family (biology)

In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 Anthocerotaceae

Anthocerotaceae

The Anthocerotaceae is the only family of hornworts in the order Anthocerotales....

. The genus is global in its distribution. Its name means 'flower horn', and refers to the characteristic horn-shaped sporophyte

Sporophyte

All land plants, and some algae, have life cycles in which a haploid gametophyte generation alternates with a diploid sporophyte, the generation of a plant or algae that has a double set of chromosomes. A multicellular sporophyte generation or phase is present in the life cycle of all land plants...

s that all hornworts produce. The dark color of the spore

Spore

In biology, a spore is a reproductive structure that is adapted for dispersal and surviving for extended periods of time in unfavorable conditions. Spores form part of the life cycles of many bacteria, plants, algae, fungi and some protozoa. According to scientist Dr...

s is the easiest way to distinguish Anthoceros from the related genus Phaeoceros

Phaeoceros

Phaeoceros is a genus of hornworts in the family Notothyladaceae. The genus is global in its distribution. Its name means 'yellow horn', and refers to the characteristic yellow spores that the plants produce in the horn-shaped sporophyte. The genus Phaeoceros was first recognized in 1951 by...

, which produces spores that are yellow.

The genus is distinguished by having spores that are dark brown to black, a relatively frilly thallus

Thallus (tissue)

Thallus, from Latinized Greek θαλλός , meaning a green shoot or twig, is the undifferentiated vegetative tissue of some organisms in diverse groups such as algae, fungus, some liverworts, lichens, and the Myxogastria. Many of these organisms were previously known as the thallophytes, a polyphyletic...

when compared to Phaeoceros, and larger and more internal cavities than Phaeoceros.