lEMKACEJS. 487 



I. ARUM. ARUM. 



Spatlia large, convolute (the edges rolled over each other) at the base. No 

 perianth. Pistils or female flowers at the base of the spike. Stamens or 

 male flowers above them ; the club-shaped summit of the axis without 

 flowers. Berry with 1 or very few seeds. 



A genus sometimes limited to a very few species, from Europe and tem- 

 perate Asia, sometimes extended so as to comprehend a large pertion of the 

 Aroidea of the northern hemisphere without the tropics. 



1. Common Arum. Arum maculatum, Linn. 

 (Eng. Bot. t. 1298. Cuckoo-pint. Wake-robin. Lords-and-Ladies.) 

 Bootstock an acrid, white tuber. Leaves on long, radical footstalks, 

 ovate-hastate ; the lobes of the base straight or shortly diverging, of a dark, 

 shining green, sometimes spotted with purple or marked vsith pale-whitish 

 veins. Spatha 6 to 8 inches long, obUquely campanulate, tapering to a point 

 at the top, the convolute part contracted above the base. Spike half con- 

 cealed in the spatha, the club-shaped yellow or purphsh top alone appearing 

 above the convolute part. Berries bright red, in a short spike, on a naked 

 peduncle, the leaves and spatha having died away before they are ripe. 



In woods and thickets, under hedges, etc., chiefly in central Europe, from 

 northern Italy and Spain to southern Scandinavia. Frequent in England 

 and Ireland, rare in southern Scotland. Fl. spring. The white-veined 

 variety from the Isle of Wight has been mistaken for the south European 

 A. italicum. 



II. ACORUS. ACOEUS. 



A single species, distinguished as a genus by the leaf-like spatha not en- 

 closing the spike, and by the numerous hermaphrodite flowers consisting of 

 a perianth of 6 short scales, 6 stamens, and a 2- or 3-ceUed ovary, all closely 

 packed in a dense, cylindrical spike. 



1. Sweet Acorus. Acorus calamus, Linn. 

 (Eng. Bot. t. 356. Sweet Flag. Sweet Sedge.) 



A highly aromatic, reed-like plant, with a thick, shortly creeping root- 

 stock. Leaves linear and erect, 2 or 3 feet long, about half an inch broad. 

 Flowering-stem simple and erect, the long, linear, leaf-hke spatha forming a 

 flattened continuation, with the spike sessile at its base so as to appear 

 lateral ; it is cylindrical, very dense, 2 to 3 inches long, of a yeUowish-green 

 colour. 



On the edges of lakes and streams, all over Europe, except the extreme 

 north ; rare in the most western States, but extends all across Russian and 

 central Asia into North America. In Britain, beUeved to be indigenous 

 only in some of the eastern counties of England, but has be«n introduced 

 into many parts of England and southern Scotland. Fl. summer. 



LXXVI. THE DUCKWEED FAMILY. LEMNACEiE. 

 A single geuus, united by some with the Arum family, 



