Children (39 direct children, 46 direct and indirect children):
Hydrolithon arenicola
Hydrolithon boreale
Hydrolithon boergesenii
Hydrolithon breviclavium
Goniolithon breviclavium
Hydrolithon chamaedoris
Hydrolithon cruciatum
Hydrolithon cymodoceae
Hydrolithon farinosum
(tree size 3)
Hydrolithon gardineri
Hydrolithon iyengarii
Hydrolithon improcerum
(tree size 1)
Hydrolithon krusadiense
Hydrolithon masakii
Hydrolithon munitum
Hydrolithon murakoshii
Hydrolithon oligocarpum
Hydrolithon onkodes
(tree size 2)
Hydrolithon pachydermum
(tree size 1)
Hydrolithon pellire
Hydrolithon reinboldii
Hydrolithon rupestris
Hydrolithon samoënse
Hydrolithon superficiale
Hydrolithon somaliae
Hydrolithon sargassi
Hydrolithon verrucosum
Hydrolithon craspedium
Hydrolithon abyssophila
Hydrolithon braganum
Hydrolithon chamberlainiae
Hydrolithon falklandicum
Hydrolithon megacystum
Hydrolithon conicum
Hydrolithon consociatum
Hydrolithon decipiens
Hydrolithon discoideum
Hydrolithon setchellii
Hydrolithon setoense
Hydrolithon subantarcticum