ESSEX   BOTANY   AND   MYCOLOGY  GROUPS 

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Juncus ambiguus  Guss                                                                                                                                                           Frog Rush         ___________________________________________________________________________________                                                                     

This quite distinctive annual rush was recognized as a separate taxon from J. bufonius as long ago as 1905 (Songeon & Perrer as J. ranarius) but it was not until the illustrated paper by Cope and Stace Watsonia 12. 113-128. 1978 that it began to be systematically recorded in this country. By 2007 it had been recorded in around 120, mainly coastal, hectads. It is obviously more widespread in Essex than formerly thought, and may well have been overlooked. On the other hand it may be freshly colonizing the county, - the colony at Fobbing being a definite new arrival. Its more squat, bluish-green flower heads that tend to cluster at the ends of the shoots, once known, are quite distinct from J. bufonius. The tendency for the inner tepals to be blunt-rounded at the apex, and no longer than the capsule,  is diagnostic. At Jaywick, it seems to like damp-wet saline habitats at the back of the sea wall, and is particularly abundant in public car parks which suggests that the seeds may be spread by car tyres. So far it has turned up at Foulness, Fobbing Jaywick and Aveley Marshes, but now we have our eye in for it, it will probably be found to be far more widespread. At Aveley it occurs over a wide area of low saline marsh some distance from the sea.