polyantha
/ˌpɒlɪˈanθə/noun
More fully polyantha rose. Any of a group of hybrids of Rosa multiflora (originally with R. chinensis or R.× odorata, later also with hybrid tea roses), bearing small flowers in clusters.
Origin
Late 19th century; earliest use found in The Century Illustrated Monthly Magazine. From scientific Latin polyantha, former specific epithet of Rosa multiflora from poly- + ancient Greek ἄνθος flower + scientific Latin -a.