he ae THE MARESTAIL FAMILY. 
II], HIPPURIS. MARESTAIL. 
_ A single aquatic species, distinguished as a genus from Myriophgliee 
by its entire leaves, and by its flowers always without petals, witha — 
scarcely perceptible border to the calyx, and reduced to.1 stamen, 1 subu- 
late style, and 1 ovule and seed. 
1. H. vulgaris, Linn. (fig. 397). Marestail—An aquatic plant with 
a perennial rootstock, and erect, annual, simple stems, the upper part 
projecting out of the water sometimes to the height of 8 or 10 inches, i 
and crowded in their whole length by whorls of from 8 to 12 linear 
entire leaves ; the submerged ones, when in deep streams, often 2 or 
8 inches long, gradually diminishing till the upper ones are less 
than half an inch. Flowers minute, sessile in the axils of the upper 
leaves, consisting of a small globular or oblong ovary, crowned by a 
minute, scarcely perceptible border, on which is inserted a very small 
stamen, and from the centre of which proceeds a short, thread-like 
style. Fruit a little, oblong, 1-seeded nut, scarcely a line in length. 
In shallow ponds, and watery ditches, over the greater part of 
Europe, Russian and central Asia, and North America, especially in 
high latitudes, reappearing in Chili. In Britain, not near so frequent 
as Myriophyllum, except in Ireland, where it is said to be common. i. 
summer. The whole plant has a general resemblance, although no 
affinity, to some species of Hquisetum, called Horsetails or even Mares- 
tails. 
XXXV. UMBELLIFERZ. THE UMBELLATE FAMILY. 
Herbs, or, in a few exotic species, shrubs, with alternate 
leaves, often much cut or divided ; the footstalk usually dilated 
at the base, but no real stipules. Flowers usually small, in — 
terminal or lateral umbels, which are either compound, each 
ray of the general umbel bearing a partial umbel, or more rarely 
simple or reduced to a globular head. At the base of the ~ 
umbel are often one or more bracts, constituting the dnvolucre, 
those at the base of the partial umbel being termed the znvolucel. 
Calyx combined with the ovary, either entirely so or appearing 
only in the form of 5 small teeth round its summit. Petals 5. 
inserted round a little fleshy disc which crowns the ovary, 
usually turned in at the point, and often appearing notched. 
Stamens 5, alternating with the petals. Ovary 2-celled, with 
1 ovule in each cell. Styles 2, arising from the centre of the 
disk. Fruit when ripe, separating into 2 l-seeded, indehiscent 
-carpels, usually leaving a filiform central axis, either entire or 
splitting into two. This axis, often called the carpophore, is, 
however, sometimes scarcely separable from the carpels, Each — 
carpel (often called a mericarp, and having the appearance of — 
a seed) is marked outside with 10, 5, or fewer prominent 
