Charophytes of Australia’s Northern Territory - I. Tribe Chareae Author Casanova, Michelle T. Author Karol, Kenneth G. text Australian Systematic Botany 2023 2023-03-30 36 1 38 79 http://dx.doi.org/10.1071/sb22023 journal article 10.1071/SB22023 1446-5701 10904227 Lamprothamnium J.Groves, J. Bot . 54: 336 (1916) Lamprothamnus A.Braun in C . F . O .Nordstedt, Abh. Königl. Akad. Wiss. Berlin 1882: 100 (1883) , nom. illeg. [ non Hiern (1877)]; Lamprothamnion J .Olsen, Biol. Skr . 3: 82 (1944) , orth. var . Type : Lamprothamnium papulosum (Wallr.) J.Groves. Monoecious or dioecious. Plant axis ecorticate, usually narrower than the branchlets. Stipulodes in one whorl (haplostephanous), usually distinctively downward pointing, branchlets ecorticate, bract cells verticillate. Gametangia on the branchlet nodes or arranged internal or external to the axis node at the base of the branchlets. Where conjoined the antheridium usually above the oosporangium. Helical cells of the oosporangium terminated by a coronula of five cells. Oospores with a calcified covering ( gyrogonite ). Lamprothamnium has 13 extant species known from Australia ( Casanova 2013 a ) and at least two additional species in Europe, Africa and Asia. All of these species occur in brackish to saline to hypersaline habitats. When compared with ecorticate species of Chara , the species of Lamprothamnium usually have much narrower axes. The current key is largely based on the arrangement of gametangia, so several shoots should be examined and the occurrence and placement of oosporangia and antheridia noted.