monosiphonic
/ˌmɒnə(ʊ)sʌɪˈfɒnɪk/adjective
1 Zoology. Of the hydrocaulus of a colonial hydroid: composed of a single tube.
2 Botany = monosiphonous.
Origin
Late 19th century; earliest use found in Philosophical Transactions of the Royal Society of London. From mono- + siphonic.