Page:VCH Hertfordshire 1.djvu/107

 BOTANY Coleman from Dawley's Wood, Tewin. On No-Man's-Land and the other dry gravelly heaths of Mid Herts such species as Rhacomitrium canescens, which especially affect such localities, will be found. Six of the twelve British species of Pottice occur ; they are, P. recta, truncatula, intermedia^ minutula, Starkeana, and lanceolata, and of these the first and fifth are the rarest. The pleurocarpous mosses are on the whole very well represented. THE LIVERWORTS (Hepatica) Forty-four species of Hepatica? were known to the Rev. W. H. Coleman as occurring in the county, a list of them being published in Appendix V. to the Flora Hertfordiensis. Among the possessions of the Hertfordshire Natural History Society is a manuscript in Mr. Coleman's handwriting in which the localities are recorded, and these, with a few notes by other observers, were published in the Transactions of the Society in 1893.' Since that time the list has not been added to. The following are the genera represented in Hertfordshire, with the number of species in each genus MARCHANTIACE.S: Marchantia. Conocephalus Asterella Lunaria. Riccia Ricciella. Ricciocarpus JUNGERMANNIACE.S: Frullania Lejeunea Radula. Porella. . Lepidozia Odontoschisma Cephalozia. LCE.fl s Lophocolea. Chiloscyphus ! Kantia. 2 Trichocolea Blepharozia. Scapania. Diplophyllum Plagiochila. ! Eucalyx. 2 Jungermannia 7 Nardia. . I Fossombronia I Pellia. . 2 Aneura. . 2 Metzgeria. I Sphaerocarpus i ANTHOCEROTACE^: Anthoceros. . i THE STONEWORTS (Cbaracea) The stoneworts, although a very small group of plants, do not fall into any one of the larger classes. Linna?us first placed them amongst the cryptogamic plants (near the lichens), and then amongst the lower phanerogamic plants, in which view he was followed by Jussieu, De Candolle, Brown, and Leman. In 1835 Fries gave them their highest position, considering them to be dicotyledons ; a year or two later End- licher assigned them their lowest position in the middle of the Alga?, which he considered to be the lowest class of plants. Lindley in 1833 placed them between the Hepaticae and the Fungi, but in 1845 amongst the Alga?, the view held by Von Martius, Agardh, and Wallroth, all of whom considered them to be Confervae. In 1845 Brongniart placed them (doubtfully) in the Acrogens above the ferns and their allies ; and in 1857 Berkeley referred them to the same class, but put them below the Hepatica?. 2 They are now given a rank equal to that of the ferns, mosses, lichens, etc., the Algae being considered their nearest allies. 1 Trans. Herts Nat. Hist. Soc., vol. vii. p. 233. 8 See Lindley's Vegetable Kingdom, pp. xliii.-liv. and 26 (3rd ed. 1853), and Berkeley's Cryptogamie Botany, p. 424 (1857). I 65 F