Thalictrum colllnum, a very local species reported from Herts and Beds. The pasque-flower (Anemone Pulsatilla), found in all the bordering counties except Middlesex, may yet be found on the Chilterns, since it occurs on them close to the Herts border. Ranunculus Lenormandi, found only in Berks ; R. hirsutus or sardous, found in Middlesex, Herts, Beds and Berks, is not unlikely to be found in wet places in the Colne district. Cardamine impatiens, which occurs near Harrow, may also be found by some of the small ditches in the Colne drainage. The wall rocket (Diplotaxis tenuifolia), which grows on old walls, such as Windsor Castle, Reading Abbey, St. Alban's Abbey, formerly on Northampton Castle and about London, is not very likely to be found ; Thlaspi perfoliatum, a native in Oxfordshire, only occurs as a casual by the railway in Bucks, Berks, and Middlesex. Viola stagnina formerly grew in the marshy district of Otmoor in Oxford, and Elatine Hydropiper and hexandra are limited to Berk- shire, where they grow on the sandy margins of pools, but very rarely. The small- leaved lime (Tilia parvifolia) is native in Bedford Purlieus, Northants, but only occurs as a planted tree in Bucks ; and the same is true of the large-leaved species T. platyphylla, which is recorded close to the Bucks border from Stokenchurch woods in Oxfordshire. The perennial flax (Linum perenne) is an eastern species found on limestone soils in Northants, if indeed it be not extinct. The furze (Ulex Gallii), which is found on one or two commons in Oxford and Berks, may be found, but it is essentially a western form. The bird's-foot trefoil (Trigonella purpurascens), which grows in Berks, Herts and Middlesex, may yet reward the searcher on some of the gravelly commons which are suitable places for it ; and the same may be said of the clovers T. scabrum, known for all the border counties except Herts, and T. glomeratum, which grows in Middlesex and Herts. Another clover, T. ochroleucon, which occurs in Beds and Northants, is less likely to be found as it is an eastern species ; the most likely place for it would be near Olney. The blue milk vetch (Astragalus danicus), found in all the border counties except Middlesex, is very likely to be found on the Chalk escarpment, as it is common on the downs near Barton-in-the-Clay in Beds, and is locally plentiful in the limestone of east Northants.
Twenty-four brambles are found in one or other of the bordering counties which at present are unrecorded for Bucks, but several of these will certainly be found. The marsh cinquefoil (Comarum palustre or Potentilla palustris) is recorded for all the bordering counties except Middlesex ; it is a marshy species which drainage is eradicating from the midlands, but it may possibly linger in the districts of Burnham or Langley, although hitherto unfound. The burnet rose (Rosa spinosissima) and its hybrid R. involuta, which occur in Middlesex, Beds and Northants, may possibly be found on some of the heathy commons, but Brickhill, which is such a suitable place, does not appear to yield it. R. sepium or agrestis, which is found in Oxon, Berks and Middlesex, is almost certain to occur, as it grows at Watlington near Prince's Risborough as well as at Beckley in Oxfordshire, in both places not far from the county border. The navelwort (Cotyledon Umbilicus), found in Berks, Oxon and Northants, may possibly be found on some stone walls in or about villages. The large sundew (Drosera anglica) formerly, it is said, grew in Beds, but is now extinct. The starwort (Callitricbe vernalis, Kuetz, C. palustris, L.) occurs in the fen ditches of Northants, and probably may be found in our area, as it is easily overlooked for the commoner forms. The willow herb (Epilobium Lamyi), which has been found in Middlesex, is almost certain to be found ; E. lanceolatum, which is found in Berks, is less likely to be a Bucks plant. Erynglum campestre formerly grew by the Watling Street in Northants, but is not likely to be found ; but another umbellifer, Seseli Libanatis, may possibly be found on the Chilterns, since it occurs in Herts. Another plant of that county, Cicuta virosa, which was formerly reported to grow in Beds and Middlesex, is scarcely likely to be found, and I think the older botanists mistook some other species for it. The two water hemlocks Œnanthe Lachenalii and Œ. silaifolia, which occur in several of the border counties, should be found, the former in calcareous bogs, the latter in marshy meadows ; indeed, the latter grows in the Thames meadows at Runnymede in Surrey, although I have as yet failed to find it on the Bucks side of the stream. A bedstraw, Galium anglicum, found in Herts, is unlikely to be found in our county ; but the cat's-foot (Antennana dioica), which occurs on the chalk hills of Beds and Oxon and on the limestone quarries of Barnack in Northants, will possibly be found ; another composite, Inula vulgaris, a decreasing species in the midlands, reported for many of the surrounding counties, may be detected in the lower parts of the Colne district, since it occurs in Middlesex and Berks. The thistle Carduus tenuiflorus, recorded for all the border counties, is more likely to be found near the Middlesex border. The spotted cat's-ear (Hypochaeris maculata), which grows on the limestone quarries of Barnack in Northants, is absent from our area, but the marsh sowthistle (Sonchus palustris), one of the
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