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 BOTANY GENTIANE* Erytbrtga pukbella, Fries BORAGINE& Symphytum tuberosum, L. Myosotis illvatica, HofFm. Cynoglossum montanum, Lamk. CONVOLVULACE^ Cuscuta epilinum, Weihe SCROPHULARINEJE Verbascum lychnitis, L. blattaria, L. virgatum, With. Linaria spuria, Miller decumbens, Moench Melampyrum cristatum, L. OROBANCHE.* Orobanche major, L. minor, Sutt. ceerulea, Vill. LAJUATJI Mentba ntundifolia, L. Stachys ambigua, Sm. Ajuga chamaepitys, Sckreb. CHENOPODIACEJE Chenopodium ficifolium, Sm. urbicum, L. hybridum, L. murale, L. PoLYGONACE.ffi Polygonum minus, Huds. dumetorum, L. EUPHORBIACEJE Euphorbia platyphyllos, L. Mercurialis annua, L. SALICINE.S: Salix russelliana, Sm. HYDROCHARIDEJE Hydrocharis morsus-ranae, L. Stratiotes aloides, L. ORCHIDE./E Cephalanthera pallens, Rub. Herminium monorchis, Br. LILIACEJE Ruscus aculeatus, L. Polygonatum multiflorum, All. Allium oleraceum, L. Fritillaria meleagris, L. Gagea lutea, Ker JUNCE.S Juncus diffusus, Hofpe Luzula Forsteri, DC. TYPHACE.S Sparganium minimum, Fries NAIADACEJE Potamogeton rufescens, Schrad. gramineus, Fries CYPERACE./E Eriophorum latifolium, Hoppe Scbcenus nigricans, L. Carex teretiuscula, Good. baenninghausiana, Weihe gracilis, Curtis xanthocarpa, Degl. (? hybrid) strigosa, Huds. GKAHIXUK Setaria viridis, Beauv. Alopecurus fulvus, Sm. Phleum phalaroides, Koch Agrostis pumila, L. Calamagrostis lanceolata, Roth Gastridium lendigerum, Gaud. Apera spica-venti, Beauv. Bromus racemosus, L. Hordeum silvaticum, Huds. (Elymus europaeus, L.) A few plants enumerated in these lists are probably extinct. The white water-lily (Nympheea alba), first recorded for the county by Izaak Walton in his Compleat Angler (1653), is probably extinct as a wild plant. It has been eradicated from the river Lea, where Walton saw it, by nursery gardeners, and wherever it is now found, which is only in ornamental waters, it has probably been planted. The great burnet (Poterium qfficina/e, Hook, f., better known as Sanguisorba officinalis) has not been recorded since it was first gathered in 1840, near Ashwell in the Cam district. And the star-fruit (Damasonium stellatum which was first recorded from its only known locality, Totteridge Green in the Brent district, by Joseph Woods in Turner and Dillwyn's Botanist's Guide (1805), gradually became scarcer, and could not be found there by Coleman in 1858. On the other hand several species of recent introduction are becoming thoroughly estab- lished and are gradually extending their range in the county. The most interesting of these are the two smaller balsams (Impatiens fiilva and parviflora). The presence of the former on the banks of the Grand Junction Canal at Harefield was first recorded in 1869, and by 1875 it had spread up the valleys of the Colne and Gade, through Rickmansworth and Cassiobury Park, to Hunton Bridge above Watford. The latter was first noticed at Essendon in the Lea district in 1874, and has since appeared in Cassiobury and Ashridge Parks in the Colne dis- trict. The American water-weed (Elodea canadensis of Hooker's flora, much better known as Anacharh ahlnastrum) was introduced into England about the year 1841 ; in 1852 or 1853 '* was first noticed to be nearly choking the river Colne at Watford; and by 1881 it had 59