MARE'S-TAIL TRIBE 9 



2. Spiked Water Milfoil (Tlf. spicdfum).- — Flowers wliorled, longer than 

 the ISracts at their base, which form an interrupted leafless spike ; stem slender 

 and branched. Plant perennial. This is a common plant in standing pools, 

 where it forms entangling masses by its slender stem and branches, which, 

 when we take them from the water and shake them, drop numerons little 

 living creatures, that have evidently found a home amid the leaves and bracts. 

 The whole plant looks very green and pretty, as it lies in the water, where it 

 floats below the surface, save when in July and August its spikes of minute 

 greenish flowers rise just above the pool. These spikes are from three to five 

 inches long, and the leaves, which are four in a whorl, are cut into slender 

 segments. 



3. Alternate-flowered Milfoil (i/. alter niflomm). — Barren flowers 

 arranged alternately on a short leafless spike ; fertile flowers about three 

 together, in the axils of the leaves at its base ; spikes drooping when in bud. 

 Plant perennial. This rare species occurs in a few places in England and 

 Scotland in ponds and ditches, its small green flowers appearing from May to 

 August. It is very similar to the last species, but is more slender, and its 

 flowers are less abundant. 



3. Water Starwort {CalUtrkhe). 



1. Vernal Water Starwort (C vSrna). — Leaves in pairs, united at the 

 base ; flowers in the axils of the leaves, usually containing one stamen or one 

 pistil only, but occasionally both organs ; carpels bhintly keeled at the back. 

 Plant annual. This little Starwort is abundant in ditches, pools, and slow 

 streams, everywhere, and is often probably mistaken by those little familiar 

 with plants, for some species of bedstraw {Galium). Its shoots are most 

 truly starry, the leaves being crowded on the top of the slender stem, and 

 often the plant when in masses forms thick tufts like green cushions in the 

 pools lying among the grass of marshy lands. The verdure is of emerald 

 hue, and numerous little white hair-like shining roots proceed from the joints 

 of the stem, forming a characteristic feature of the Starwort. The foliage is 

 submersed, but the stamens of the little green flowers in June and July rise 

 just above the surface of the water. The Starwort is called by the French La 

 Callitric, and by the Germans Wassersten. It is the Callifrica of the Italians, 

 and the Sterrekruid of the Dutch. Several varieties or sub-species are described, 

 one having the lobes of the fruit slightly keeled, another with the lobes 

 slightly winged at the back. 



2. Pedunculated Water Starwort (6*. pedimaddta). — Fruit-stalks 

 without bracts at the base ; fruit 4-sided, each lobe bluntly keeled at the 

 back. Plant annual. This rare species is very nearly allied to the last, of 

 which it is probably a sub-species. It is found in ditches in Sussex, and some 

 other English counties, as well as in Wales, producing its inconspicuous flowers 

 somcAvhat earlier than 0. verna. 



3. Autumnal Water Starwort (6'. aidumndlis). — Fruit-stalks very 

 short, without bracts ; fruit somewhat 4-sided, each lobe winged at the back. 

 Plant annual. This species occurs about London, in various lakes from 

 Scotland to Devonshire, and in Ireland. It flowers in June and July. A 

 variety known as C. truncata is distinguished by having its fruit keeled. 



II.— 2 



