A HISTORY OF ESSEX (Gentiana amarelld), deadly nightshade (Atropa Belladonna), the dwarf orchis (Orchis ustulatd), the pyramidal orchis (O. pyramidalis), the green man orchis (Aceras anthropophord) , bee orchis (Opbrys apiferd), spider orchis (O. araniferd), the fly orchis (O. musciferd), large white helle- borine (Cephalanthera pat/ens), and other chalk plants. London clay is perhaps remarkable for the limited character of its flora. In the summer the surface dries and becomes so hard that a pick can scarcely penetrate it, whilst below it retains much moisture. It favours those plants which send their roots deep into the soil, e.g. colts- foot (Tussilago Farfard), which is common on undrained London clay. Thymus Chamcedrys also favours this formation, whilst wild oat (Avena fatud] is peculiarly abundant on it. The gravels and sands possibly stand next to chalk for the variety of characteristic plants which these soils produce in the county. The following may be mentioned as characteristic of these formations : the interesting mouse's-tail (Myosurus minimus), the small-flowered ranunculus (Ranunculus parviflorus) , flixweed (Sisymbrium Sophia], swine's cress (Sene- biera Coronopus), lesser swine's cress (S. didymd), dog violet (Viola canind), Deptford pink (Dianthus Armerid), English catchfly (Silene anglicd), purple sandwort (Spergula rubrd), trailing St. John's wort (Hypericum humifusum), upright St. John's wort (H. pulchrum), allseed (Radio/a millegrand), needle whin (Genista anglicd), hare's foot trefoil (Trifolium aruense), lesser trefoil (T. minus), slender trefoil ( T. Jiliforme), annual knawel (Scleranthus annuus), purple-tipped cudweed (Filago apiculatd), field cudweed (F. minima), narrow-leaved cudweed (F. Gallicd), slender-flowered thistle (Carduus tenuiftorus), common sheep's scabious (Jasione montand), downy hemp nettle (Galeopsis ochroleucd), and the pretty little orchid 'lady's tresses' (Spiranthes autumnalis] . The riverside and alluvium flora is well represented ; amongst these plants we have the common meadow-rue (Thalictrum flaiium), greater spearwort (Ranunculus Lingua), white water lily (Nymphcea alba), yellow water lily (Nuphar luteuni), bitter ladies' smock (Cardamine amard), purple loosetrife (Lythrum Salicaria, L.), the willow herbs (Epilobium), common hare's-tail (Hippuris vu/garis), whorled water-milfoil (Myriophyllum verti- cillatum), spiked water -milfoil (M. spicatum), meadow-sweet (Spiraea Ulmarid), common marsh wort (Helosciadium nodiflorum), the very poisonous water drop worts (CEnanthe), common valerian (Valeriana qfficinalis), small teasel (Dipsacus pilosus], hemp agrimony (Eupatorium cannabinum), bur marigold (Bidens tripartita and B. cernud), yellow rattle (Rhinanthus Crista-galli), most species of the mints (Mentha rotundifolia, M. aquatica, M, syhatica, M. viridis, M. piperita, M. pratensis, M. sativa), scullcap (Scute llaria galericulatd), water violet (Hottonia palustris), yellow loosestrife (Lysimachia vu/garis), great water dock (Rumex Hydrolapathum), yellow flag (Iris pseudacorus], great flowering rush (Butomus umbellatus), sweet flag (Acorus Calamus), all the duckweeds (Lemnd), and bullrush (Scirpus lacustris) . Essex possesses a very representative marine flora. There are 36
