''Notothylas'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

of hornworts in the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Notothyladaceae The Notothyladaceae is the only family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well ...

. The genus is found globally, but is usually overlooked. It is the smallest of all the hornworts, with a yellow-green

gametophyte A gametophyte () is one of the two alternating multicellular phases in the life cycles of plants and algae. It is a haploid multicellular organism that develops from a haploid spore that has one set of chromosomes. The gametophyte is the ...

thallus Thallus (plural: thalli), from Latinized Greek (), meaning "a green shoot" or "twig", is the vegetative tissue of some organisms in diverse groups such as algae, fungi, some liverworts, lichens, and the Myxogastria. Many of these organisms ...

that is seldom more than a centimeter in diameter, and usually much smaller. The genus ''Notothylas'' is also unusual among hornworts in that the sporophyte is bullet-shaped and does not grow very large (less than two millimeters). The sporophytes grow outwards rather than upwards, and like '' Megaceros'', there are no stomata on the surface of the sporophyte. The

elater An elater is a cell (or structure attached to a cell) that is hygroscopic, and therefore will change shape in response to changes in moisture in the environment. Elaters come in a variety of forms, but are always associated with plant spores. In ...

cells do not grow

helical Helical may refer to: * Helix, the mathematical concept for the shape * Helical engine, a proposed spacecraft propulsion drive * Helical spring, a coilspring * Helical plc, a British property company, once a maker of steel bar stock * Helicoil A t ...

thickenings. Unlike many hornworts, species in ''Notothylas'' tolerate full sunlight.Module-Lower-Plants.pdf - Benson Idahosa University
/ref> A number of classification systems place ''Notothylas'' in its own order Notothyladales (frequently misspelled ''Notothylales'' in the literature). This classification is based on the assumption that the unique physical characteristics of the genus reflect an early divergence from other hornworts. However, this assumption is not supported by either phylogenetic analysis or fossil evidence. More recent classifications expand the definition of the family

to include four other genera.

References

* Asthana, A. K. & Srivastava, S. C. (1991). ''Indian Hornworts (A Taxonomic Study)''. J. Cramer: ''Bryophytorum Bibliotheca'', Band 42. . * Hässel de Menendez, G. G. (1988). A proposal for a new classification of the genera within the Anthocerotophyta. ''J. Hattori Bot. Lab.'' 64: 71-86. * Hicks, Marie L. (1992). ''Guide to the Liverworts of North Carolina''. Durham, NC: Duke University Press. . * Prihar, N. S. (1961). ''An Introduction to Embryophyta, Volume I''. Allahbad: Central Book Depot. * Singh, D. K. (2002) "Notothylaceae of India and Nepal(A Morpho-taxonomic revision). Bishen Singh Mahendra Pal Singh, Dehradun.

External links

{{Taxonbar, from=Q7063283 Hornworts Bryophyte genera