96 



CALYCIFLOR.E 



nut-like. From the Greek words, hippos and oura, meaning a 

 horse's tail.) 



2. Myriophyllum (Water Milfoil). Stamens and 

 pistils in separate flowers, but on the same plant 

 (monoecious) ; calyx 4-parted ; petals 4 ; stamens usually 

 8 ; styles 4 ; fruit of 4 nut-like seeds. (Name from the 

 Greek, murios, countless, and phyllon, a leaf, from its 

 numerous leaves.) 



1. Hippuris (M are' s-tail) 



1. H. vulgaris (Common Mare's-tail). The only 



British species, not uncommon in stagnant water. A 



singular plant, with erect, jointed stems, which are un- 



branched, except at the base, and taper to a point, 



bearing whorls of 8-12 very narrow leaves with hard 



tips. The inconspicuous flowers are sessile in the axils 



of the upper leaves, and are often without stamens. 



Not to be confounded with the genus, Equisetum 



Vulgaris (Horse-tail), a plant allied to the ferns, which has a 



(Common jointed stem and rigid leaves, but bears its fructifica- 



Mare' s-tail) tion in terminal heads. Fl. June, July. Perennial. 



2. Myriophyllum (Water Milfoil) 



1. M. spicatum (Spiked Water Mil- 

 foil). An aquatic plant, rooting in 

 the mud of stagnant waters, and form- 

 ing a tangled mass of slender, much 

 branched stems ; leaves 4 in a whorl, 

 finely divided into numerous hair-like 

 segments, the whole plant being sub- 

 merged, except the leafless, slender 

 spikes of inconspicuous greenish flowers, 

 arranged in whorls, which rise a few 

 inches above the surface. Common. 

 Fl. July, August. Perennial. 



2. M. verticillatum (Whorled Water 

 Milfoil). Differs from the preceding in 

 having the flowers in whorls at the base 

 jf the leaves. M. allemiflorum (Alter- 

 nate Flowered Water Milfoil) has barren flowers, alternately 

 arranged in a short, leafless spike, with the fertile flowers, 

 about 3 together, in the axils of the leaves at its base. The last 

 two are rare. 



Myriophyllum Spicatum 

 (Spiked Water Milfoil) 



