The floating liverworts of Essex How it spreads is a mystery. It is presumed to be dioecious, but archegonia, antheridia and sporophytes are rarely found. Sex organs apparently only develop, if at all, on stranded thalli around November time, and may therefore be overlooked. The sporophytes are embedded in the gametophyte thallus and bulge downwards as spherical swellings on the underside of the straps. Small floating thalli arc probably also spread around on birds feet, so much of its dispersal, at least in Britain, may be vegetative. In Essex it is widespread in occurrence, except on the chalk and boulder clays, occurring most commonly in old gravel and clay working ponds, often persisting for decades, though mysteriously failing to appear in some years. [Closely related to two other aquatic liverworts R. rhenana and R. canaliculata that occur in Britain]. TQ(51)39 is Chingford, Epping forest, 1927 D.G.Catcheside. The Warren Pond, opposite Queen Elizabeth's hunting Lodge, Epping Forest, marsh at southern end. 1985 & 1986, Kenneth J Adams. Oak Hill, Woodford, Epping Forest, the third small pond in from Oak Hill road, on marginal mud. 11 July 1970. Kenneth J Adams. Ponds by Galley Hill Wood. 1959. Eric Saunders. Epping Forest, in pond attached to Utricularia. April 1942. J.H.G.Peterken (BBS Herbarium, National Museum of Wales, Cardiff). Church Road Pond, Buckhurst Hill, 1967. Kenneth J Adams. Cuckoo Pits, Epping Forest 1920. Joseph Ross. (Essex Naturalist 21: 303). Cuckoo Pits, 1950. J.H.G.Peterken. Fairmead Bottom Pond, Epping Forest. 1959, Eric Saunders; August 1981, KennelhJ Adams. Oak (Speakman's) Pond, High Beach, numerous small patches on wet mud in the SW bay of drying up pond, 9 July 2004, Kenneth J Adams. Earl's Path Pond, Epping Forest, 1964. Alan J Harrington; 1967 Bernard T Ward; 1974, Kenneth J Adams. Goldings Hill, Epping Forest, in one of the ponds, 1905. Essex Naturalist 14: 276. Golding's Hill (upper?) Pond, November 1924. Paul W Richards; Main hepatic collection. Reg.No: 52.112.1 National Museum of Wales. Cardiff. Golding's Hill Lower Pond, extensive floating rafts, 8 Februaryl987, Kenneth J Adams (present from 1981-1989). Golding's Hill Upper Pond, as blankets among marginal vegetation, 1981-1989. Kenneth J Adams. Little Valley Wake Pond, 1973, Katherine Adiemka. Chigwell, pond just west of pudding lane, 1970 (now built on). Kenneth J Adams. Hainault, Hoghill Pond, 1800. Edward Forster. Pestle Pits Pond, Epping Forest, date? Bernard T Ward. Hawcock Pond, Epping Forest, abundant on mud and overhanging banks, no floating plants, July 1980. Kenneth J Adams. Bell Common Pond North, continuous carpels on mud of dried up pond, September 1986, Kenneth J Adams, (pond subsequently dredged winter 1986/7 by Epping Forerst Conservation Volunteers). Gravel Working Ponds near St. Margarets Hospital, Epping, date 1980s, Kenneth J. Adams. 392,945 18 395,911 18 TL(52)30 398,037 19 TQ(51)49 18 408,941 18 401,957 18 409,965-7 409,979 18 415,967 18 428,979 18 428,980 18 & 429,980 421,986 18 455,944 18 47,92 18 TL(52)40 441,006 19 442,007 19 454,016 19 47,03 19 Essex Naturalist (New Series) 21 (2004) 147