DICOTYLEDONES. 65 
Genus CLXXVII.—MERCURIALIS (Linn.), Mercury. 
366. M. PERENNIS (Linn.) 
Recorded by Miss Boswell. Dr Fortescue thinks 
this is probably a mistake. 
OrpvEeR XLIV.—CERATOPHYLLACE. 
Genus CLXXVIII—CERATOPHYLLUM (Linn.) 
367. C. DEMERSUM (Linn.), Common Hornwort. 
Loch of Ayre; Kirbuster (R. Heddle). I have 
never found this plant. 
OrpER XLV.—UTRICACE. 
Genus CLXXIX.—URTICA (Linn.), Wettle. 
368. U. urENS, Small Nettle. Common. 
369. U. pioica, Great Nettle. Common. 
OrpDER XLVI.—CUPULIFER. 
Genus CLXXX.—CORYLUS (Linn.), Hazel. 
370. C. AVELLANA (Linn.) 
Berriedale and elsewhere in Hoy. 
Genus LXXXI.—BETULA (Linn.) 
371. B. ALBA (Linn.), Common Birch. 
In several places in Hoy (Dr Boswell); my speci- 
mens are from Hoy (2nd July 1902). 
F 
