LIST OF SPECIES RECORDED FROM ESSEX. 35 Ceratiomyxa fruticulosa (Muell.) Macbride.—Abundant on decayed logs and stumps ; appearing from June to September, and, rarely, in October. Badhamia populina Lister.—This species was first found on a wood pile at Walthamstow by Miss Jessie Lloyd in June 1899. In November 1902, it appeared in showy white masses that could be seen yards away on the under side of fallen poplars in the Avenues, Leytonstone. Since then, we have found it most years, usually in autumn and winter, in Wanstead Park and in the surrounding district where poplars have fallen. Several developments may succeed each other for a few weeks, but there appears to be only one main crop a year. It is an abundant species in Colorado, where it occurs on the bark of poplar and Acer Negundo. B. utricularis (Bull.) Berk.—Common in Epping Forest on old logs of oak and hornbeam, appearing throughout the year when the seasons are moist, but especially abundant from autumn to spring. The plasmodium subsists on leathery fungi, and, in seasons that are unfavourable to these fungi, B. utricularis will be scarce. When developed under unfavourable conditions, the fructification, instead of forming the usual grape-like clusters of sporangia, has been found to extend in a flattened network of veinlike plasmodiocarps. B. foliicola Lister.—First identified as a distinct species in September 1896, when it occurred in vast abundance in Wanstead Park on half-dead turf under elm trees and on heaps of dead sycamore, elm, and bramble leaves, and also on twigs. It usually reappears there every autumn. It has been recorded now from nine English counties, as well as from Scotland, France, Germany, Switzerland, and Portugal. It is closely allied to B. utricularis, differing in having free, not clustered spores, and in feeding on dead leaves and not on leathery fungi. It has made its appearance every month from June to January. B. panicea (Fries) Rost.—This variable species is fairly abundant from summer to winter on the bark of fallen trees, especially of elms and poplar. The white or grey sporangia vary much in size. They are usually sessile and clustered on a red-brown membranous hypothallus, but sometimes we meet with scattered sporangia having short dark red stalks. B. macrocarpa (Ces.) Rost,—Not common. It has been