Tetrathylacium

{{Short description|Genus of flowering plants in the family Salicaceae}}

{{Automatic taxobox

| image = Edmonstonia pacifica.png

| image_caption = Botanical drawing of Tetrathylacium macrophyllum from 1853

| taxon = Tetrathylacium

| authority = Poepp.

| type_species = Tetrathylacium macrophyllum

| type_species_authority = Poepp.

| subdivision_ranks = Species

| subdivision = 5; see text

| synonyms = *Edmonstonia Seemann

}}

Tetrathylacium is a genus of flowering plants in the family Salicaceae. The genus spans across South America and parts of Central America, as far north as Costa Rica, and as far south as Bolivia.

Previously it was treated in the family Flacourtiaceae{{cite journal |last1=Lemke |first1=David |title=A synopsis of Flacourtiaceae |journal=Aliso |date=1988 |volume=12 |pages=29–43|doi=10.5642/aliso.19881201.05 |doi-access=free }} but was moved along with its close relatives to the Salicaceae based on analyses of DNA data.{{cite journal |doi=10.2307/4110825 |first=Mark W. |last=Chase |author2=Sue Zmarzty |author3=M. Dolores Lledó |author4=Kenneth J. Wurdack |author5=Susan M. Swensen |author6= Michael F. Fay |year=2002 |title=When in doubt, put it in Flacourtiaceae: a molecular phylogenetic analysis based on plastid rbcL DNA sequences |jstor=4110825 |journal=Kew Bulletin |volume=57 |issue=1 |pages=141–181|bibcode=2002KewBu..57..141C }} Tetrathylacium is rather unique in the Samydaceae in having tightly arranged panicles of spikes, four sepals and stamens, and non-arillate seeds.{{cite journal |last1=Sleumer |first1=Hermann |title=Flacourtiaceae |journal=Flora Neotropica |date=1980 |volume=22 |page=1–499}} The stems are often inhabited by ants, and T. macrophyllum is suspected to have locust pollination.{{cite journal |last1=Schmelz |first1=V. |last2=Weber |first2=A. |title=Tetrathylacium macrophyllum (Flacourtiaceae/Salicaceae) – the first case of locust pollination? |journal=Beitr. Naturkunde Oberösterr. [abstract] |date=2006 |volume=16 |page=577}}