BOTANY Mentha hirsuta {continued) b. subglabra (Baker) c. citrata (Ehr.) — sativa, Linn. b. paludosa (Sole) . c. subglabra. Baker — rubra, Sm — gracilis, Sm. b. cardiaca, Baker . — gentilis, Linn. NC NC NC NC NC NC NC SC SC SC SC SC SC W W Mentha gentilis (conttnuei) b. Wirtgeniana(F.Schultz) c. Pauliana (F. Schultz) . — arvensis, Linn b. Nummularia (Schreb.) c. agrestis (Sole) d. praecox (Sole) e. Allionii (Bor.) — Pulegium, Linn. . b. erecta, Syme ) £ NC SC E SC E NC SC E NC SC E NC E NC SC NC SC NC SC E w w w w w w NAIADACEiE The county is very rich in this Order, both the 'Broad* country in the east and the ' Fen ' land in the west giving unusually favourable habitats for it. The list has been most kindly corrected by Mr. Arthur Bennett, who is the acknowledged authority on the Order, and it con- tains Naias marina, discovered by him in 1883, and only known in Great Britain in the locality in which he found it. NAIADACEiE Triglochin palustre, Linn. — maritimum, Linn. Potamogeton natans, Linn — polygonifolius. Pour. . — coloratus, Hornem. . — alpinus, Balb. . — heterophyllus, Schreb. — lucens, Linn. . b. acuminatus, Fr. — decipiens, Nolte . — angustifolius, Presl. — praelongus, Wulf. . — perfoliatus, Linn. . — crispus, Linn. . b. serratus (Huds.). — densus, Linn. . E NC SC w E NC w E NC SC w E NC SC IV E SC w E NC SC w E SC w E NC SC IV E NC SC E NC w E NC SC w E NC SC w E E NC SC w Potamogeton zoster«Efolius,Schum. — acutifolius. Link. . b. major, Fieber . — obtusifolius, Mert & Koch — Friesii, Rupr — pusillus, Linn b. tenuissimus, Koch . — trichoides, Cham. . — pectinatus, Linn. . . . — interruptus. Kit. . . . b. scoparius .... var. pseudo-marinus . Ruppia spiralis, Hartm. . — rostellata, Koch . Zannichellia palustris, Linn. . — pedunculata, Reichb. . Zostera marina, Linn. Naias marina, Linn. . E E NC E E NC SC E NC E NC SC E NC E NC SC E NC SC E E E E NC NC E NC NC SC E NC E PV w w w w w w w w w w w FILICES EQUISETACEiE, LYCOPODIACE/E, MARSILEACEiE Ferns which can only grow on rocks are of course absent from the county, but their absence is made up for by the extraordinary abundance and variety of those species which are found in marshes. Lastraa cristata has certainly been found in all four divisions, though it is to be feared that in one of them, the North-Central, it is almost, if not quite, extinct. With it in some of its localities grows L. uliginosa and also L. spinulosa, but the last is common compared with the two former. In some of the marshes along the Bure and in the Broad country L. Thelypteris is as abundant as Pteris aquilina on the heath-land, and is mown and used like it for packing and rough litter. Osmunda regalis has been harried by collectors for sale until many of its clumps have disappeared ; 57
