Megaceros

{{Short description|Genus of hornworts}}

{{For|the prehistoric deer|Megaloceros}}

{{Automatic taxobox

| image = New Zealand Mosses Am media-v-838759 (cropped).jpg

| image_caption = Unidentified Megaceros specimen

| taxon = Megaceros

| authority = Campbell{{cite journal | last=Campbell | first=D.H. | year=1907 | title=Studies on some Javanese Anthocerotaceae. I. | journal=Annals of Botany | location=London | volume=21 | issue=4 | pages=467–486 | doi=10.1093/oxfordjournals.aob.a089148 | url=https://zenodo.org/record/2466140 }}

| subdivision_ranks = Species

| subdivision = Megaceros aenigmaticus

Megaceros alatifrons Steph.

Megaceros denticulatus

Megaceros flagellaris (Mitt.) Steph.

Megaceros gracilis

Megaceros guatemalensis Steph.

Megaceros novae-zelandiae Steph.

Megaceros pallens (Steph.) Steph.

Megaceros pellucidus (Colenso) E.A. Hodgs.

Megaceros salakensis D. Campb.

Megaceros tjibodensis D. Campb.

}}

Megaceros is a genus of hornworts in the family Dendrocerotaceae. The genus is found in the Old World tropics of east Asia and Australia.{{cite journal | last=Villarreal | first=J.C. |author2=Goffinet, B. |author3=Duff, R.J. |author4= Cargill, D.C. | year=2010 | title=Phylogenetic delineation of Nothoceros and Megaceros (Dendrocerotaceae) | journal=The Bryologist | volume=113 | issue=1 | pages=106–113 | doi=10.1639/0007-2745-113.1.106}} Its name means 'big horn', and refers both to the exceptionally large size of the gametophyte thallus and to the large, horn-shaped sporophyte that the plants produce. Many species have a branching thallus that is more than two centimeters wide. The gametophytes are monoicous.

The genus Megaceros is unusual among hornworts in that the sporophyte does not have stomata, and the spores are green because they contain chloroplasts, as does the related genus Dendroceros. They can have as many as 14 chloroplasts per cell, the highest known number in hornworts.[https://www.bfa.fcnym.unlp.edu.ar/catalogo/doc_num.php?explnum_id=2871 Bryophyte Biology] The elaters are helical.

The genus Megaceros was first recognized in 1907 by D. Campbell. More recently, the genera Nothoceros and Phaeomegaceros have been split off from this genus. The former genus includes all New World species previously included in Megaceros.