172 THE JOURNAL OF BOTANY 



abundant in a marsh at Lower Dounreay, and near the Isault 

 Burn, Eeay. 



"' C. aquatilis x Goodenoioii. 108. By the Mudal Water, 

 Altnaharra ; sterile, and just intermediate. 



C. capillaris L., var. major Blytt. 108. Mr. Bennett so names 

 luxuriant specimens (up to fifteen inches high) from wet coast slopes, 

 Armadale Bay. We formerly collected it at Betty Hill, and at 

 Ardskinid Point, near Tongue. Apart from the size, I can detect 

 no good varietal character. 



C. extensa Good., var. immila And. 109. Scarce on the shore, 

 east of Eeay, associated with C. Oederi Retz. ; but they do not 

 appear to produce hybrids. 



Phalaris arundinacea L., var. incta L. 109. Marsh at Lower 

 Dounreay, with the type, in great abundance. 



Agrostis alba L., var. ■'■ maritima Meyer. 108. Rocks at 

 Bighouse Cove, near Melvich. 



Arrlienathenim precatorium Dietrich [A. elatius Mert. & Koch, 

 var. hidhosum PresL). 108, 109. Melvich ; Lower Dounreay. 

 Probably not uncommon, but easily overlooked. 



Chara vidgaris L. 109. A very pretty deep-water form, of a 

 clear, light green, not incrusted, grows in the fountain at Thurso 

 Castle ; Mr. J. Groves gives it no special name. 



''■' C. hispida L. 109. A small fresh-w^ater pool on the coast, 

 east of Reay, is full of a light-brown, flexible, hardly fetid state. 

 Named by Mr. Groves. 



HYDRILLA VERTICILLATA IN BRITAIN. 

 By G. Claridge Druce, M.A. 



One of the most interesting additions made to the British 

 Flora in recent years is that of the above-named aquatic, which 

 was discovered in 1914 by Mr. W. H. Pearsall in Esthwaite Water, 

 Lake Lancashire (see Journ. Bot. 1914, 257 t. 534), in which 

 locality he kindly showed it me last August, and in which, from 

 its abundance, it cannot have been recently introduced. 



Hydrilla has also spread (assuming that it is adventitious) into 

 Australia, w^iere it is rapidly increasing ; it also occurs in Africa, 

 and is said to be found in various modifications in the lake systems 

 of Lithuania, Pomerania, and Russia. Nyman, however (Consp. 

 Fl. Europ. Suppl. ii, 285, 1890), says : " Patria hujus plantae est 

 Indise Orient ubi frequens dicitur (sed planta rossica dubia est ex 

 Ledeb.)." 



The Lancashire plant does not agree with var. Boxhurghii 

 Caspary — the common Indian form — but closely resembles the 

 Pomeranian plant (Udora piomerajiica Reichb., Ic. Fl. Germ, vii, 

 31) which Caspary names and describes as H. dentata var. pome- 

 ranica (Bot. Zeit. xii, 56, 1854 ; xiv, 901, 1856) ; he prefers to use 

 the name gracilis instead of pomeranica which he had formerly 



