''Myriocarpa'' is a

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

woody plant which ranges in size from

shrub A shrub (often also called a bush) is a small-to-medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees ...

s to small

tree In botany, a tree is a perennial plant with an elongated stem, or trunk, usually supporting branches and leaves. In some usages, the definition of a tree may be narrower, including only woody plants with secondary growth, plants that are ...

s and is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

Central Central is an adjective usually referring to being in the center of some place or (mathematical) object. Central may also refer to: Directions and generalised locations * Central Africa, a region in the centre of Africa continent, also known as ...

and

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...

. Within the Urticaceae, ''Myriocarpa'' is characterized by long pendulous string-like female

inflorescences An inflorescence is a group or cluster of flowers arranged on a Plant stem, stem that is composed of a main branch or a complicated arrangement of branches. Morphology (biology), Morphologically, it is the modified part of the shoot of sperma ...

of apparently naked

flowers A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants (plants of the division Angiospermae). The biological function of a flower is to facilitate reproduction, usually by providing a mechani ...

and stems which release a watery

latex Latex is an emulsion (stable dispersion) of polymer microparticles in water. Latexes are found in nature, but synthetic latexes are common as well. In nature, latex is found as a milky fluid found in 10% of all flowering plants (angiosperms ...

when cut. Estimates for the diversity of the genus range from five to eighteen

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

.Burger, W. 1977. Myriocarpa, Flora Costaricensis. Fieldiana, Botany 40: 237-240.Friis, I. 1989. The Urticaceae: a systematic review. In P. R. Crane and S. Blackmore ds. Evolution, systematics, and fossil history of the Hamamelidae, vol. 2, Systematics Association Special Volume 40B, 285–308. Oxford Science Publications, Oxford, UK Research for Flora Mesoamericana indicates that there are probably fifteen to twenty species. The genus was described by George Bentham in 1846Bentham, G. 1846. The botany of the voyage of H.M.S. Sulphur 168, t. 55. based on Colombian specimens of '' Myriocarpa stipitata'' collected by Mss. Barclay. Weddell placed ''Myriocarpa'' in the Urticaceae tribe BoehmerieaeWeddell, H. A. 1856. Urera. In G. Baudry and J. Baudry ds. Monographie de la famille des Urticacées. 484–490. G. and J. Baudry, Paris, France.Weddell, H. A. 1869. Myriocarpa. In A. De Candolle d. Prodromus systematis naturalis regni vegetabilis 16, 23533–23536. Paris, France. despite its anomalous pubescence,

cystolith Cystolith (Gr. "cavity" and "stone") is a botanical term for outgrowths of the epidermal cell wall, usually of calcium carbonate, formed in a cellulose matrix in special cells called lithocysts, generally in the leaf of plants. Cystoliths are pr ...

morphology Morphology, from the Greek and meaning "study of shape", may refer to: Disciplines *Morphology (archaeology), study of the shapes or forms of artifacts *Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies, ...

and wood anatomy. In his review of the Urticaceae, Friis retained its position within the Boehmerieae, presumably because its position in any other Urticaceae tribe would be equally ambiguous. The position of ''Myriocarpa'' within the Boehmerieae is not supported by recent

phylogenetic In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

analyses of trnL-F sequence dataMonro, A.K. 2006. The revision of species-rich genera: a phylogenetic framework for the strategic revision of Pilea (Urticaceae) based on cpDNA, nrDNA, and morphology Am. J. Botany 93: 426-441 that recovered ''Myriocarpa'' within a strongly supported

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

including both the Urticeae and Lecantheae tribes. Its position within either one of these tribes however, is unresolved. Based on hair, leaf and flower morphology, Myriocarpa could equally well be placed in the Lecantheae (absence of hooked hairs) or the Urticeae (alternate leaves, pistillodes not ejecting the

achene An achene (; ), also sometimes called akene and occasionally achenium or achenocarp, is a type of simple dry fruit produced by many species of flowering plants. Achenes are monocarpellate (formed from one carpel) and indehiscent (they do not ope ...

) and further research, both

molecular A molecule is a group of two or more atoms held together by attractive forces known as chemical bonds; depending on context, the term may or may not include ions which satisfy this criterion. In quantum physics, organic chemistry, and bioche ...

and morphological, is warranted. The last major revision of the genus, at which time six species were recognized, was that of Hugh Algernon Weddell. Since this revision ''Myriocarpa'' has attracted little taxonomic interest outside of floristic treatments,Standley, P. C., & J. A. Steyermark. 1952. Pilea, Flora of Guatemala.Fieldiana, Botany 3: 404–406. despite its unusual female inflorescence morphology and ambiguous position within the Urticaceae and currently a total of 24 species names have been published.International Plant Names Index. 2006. Available at website http://www.ipni.org ccessed 1 July 2006

References

{{Taxonbar, from=Q6948249 Urticaceae Urticaceae genera