ˌsīfəˌnäkləˈdā(ˌ)lēz noun plural
Usage: capitalized
Etymology: New Latin, from Siphonocladus, type genus (from siphon- + Greek klados branch, sprout) + -ales — more at gladiator
: an order of green algae (class Chlorophyceae) originally including all multinucleate members of the class capable of vegetative division but now usually restricted to those that are apparently derived from the Siphonales and are nonseptate when young (as in the families Valoniaceae and Dasycladaceae)