NAIADACE^E 289 



Mountain woods, especially on limestone, up to 5000 feet. 

 May, June. 



The writer recently observed stunted specimens of this plant on 

 the extreme summit of Carrantual, the highest mountain in 

 Ireland. 



Distribution. Europe, Asia Minor, Caucasus. British Isles. 

 Luzula nivea DC. (Plate XXIII.) 



Stems i -3 feet high, bearing a beautiful silvery white panicle 

 of flowers ; many flowers in a cluster. Capsule trigonous, globular, 

 shorter than the perianth. 



Mountain woods, clearings, and sub-alpine slopes ; common. 

 June, July. 



Distribution. Alps, Jura, Cevennes, Central France, Corbieres, 

 Pyrenees. 



This plant is well worth cultivating in gardens, for it is quite 

 handsome. The seed is easily collected in August. 



Luzula campestris DC. and its var. multi-flora, L. nemorosa E. 

 Meyer, and L. spadicea DC. are also often seen in the lower Alpine 

 region of Switzerland. 



NAIADACE^E 



Plants usually growing in water. Leaves sheathing at the base, 

 often floating on water. Flowers green, bisexual or unisexual. 

 Perianths 3-4 lobed or o. Stamens hypogynous. Ovary of 1-4 

 carpels. Style I. One seed in each carpel. 



POTAMOGETON L. Pond-weed. 



Leaves floating and opaque or submerged and translucent, 

 stipulate or not. Perianth-segments 4, small, green. Stamens 4. 



A rather large genus spread almost all over the globe ; but with 

 only one or two representatives in the high Alps. 



Potamogeton filiformis Persoon. 



Stem^branching from the base. Leaves linear-filiform, i-nerved. 

 Spikes on long stalks. Fruit globular, with very short beak. 



Alpine lakes, and rarely lower. It is abundant at the shallower 

 end of the Lake of Mont Cenis (6300 feet) and in several Alpine 

 lakes in Switzerland. It flowers in July ; rare. 



Distribution. S. Tyrol, Switzerland, Western Alps, Central and 

 Northern Europe. British. 



Potamogeton alpinus Balbis (P. rufescens Schrad.). 



Stem simple, cylindrical ; submerged leaves narrow-lanceolate, 

 sub-obtuse, translucent ; floating-leaves, when they exist, coria- 

 ceous, oblong-spathulate, reddish. Stipules large. Fruiting-spike 



