The Collaborative International Dictionary
spongelet
Spongiole \Spon"gi*ole\ (sp[u^]n"j[i^]*[=o]l; 277), n. [L. spongiola a rose gall, small roots, dim. of spongia: cf. F. spongiole.] (Bot.) A supposed spongelike expansion of the tip of a rootlet for absorbing water; -- called also spongelet.
Wiktionary
spongelet
n. A spongiole.