male flowers, and sterile flowers forming a ring of hairs borne on the
spadix.]
The small flowers are densely crowded on thick fleshy spikes, which are
associated with, and often more or less enveloped by, a large leaf
(bract), the so-called spathe, which, as in cuckoo-pint, where it is
green in colour, _Richardia_, where it is white, creamy or yellow,
_Anthurium_, where it is a brilliant scarlet, is often the most striking
feature of the plant. The details of the structure of the flower show a
wide variation; the flowers are often extremely simple, sometimes as in
_Arum_, reduced to a single stamen or pistil. The fruit is a berry--the
scarlet berries of the cuckoo-pint are familiar objects in the hedges in
late summer. The plants generally contain an acrid poisonous juice. The
underground stems (rhizomes or tubers) are rich in starch; from that of
_Arum maculatum_ Portland arrowroot was formerly extensively prepared by
pounding with water and then straining; the starch was deposited from
the strained liquid.
The order is represented in Britain by _Arum maculatum_, a low
herbaceous plant common in woods and hedgerows in England, but probably
not wild in Scotland. It grows from a whitish root-stock which sends up
in the spring a few long-stalked, arrow-shaped leaves of a polished
green, often marked with dark blotches. These are followed by the
inflorescence, a fleshy spadix bearing in the lower part numerous
closely crowded simple unisexual flowers and continued above into a
purplish or yellowish appendage; the spadix is enveloped by a leafy
spathe, constricted in the lower part to form a chamber, in which are
the flowers. The mouth of this chamber is protected by a ring of hairs
pointing downwards, which allow the entrance but prevent the escape of
small flies; after fertilization of the pistils the hairs wither. The
insects visit the plant in large numbers, attracted by the foetid smell,
and act as carriers of the pollen from one spathe to another. As the
fruit ripens the spathe withers, and the brilliant red berries are
exposed.
The sweet-flag _Acorus Calamus_ (q.v.), which occurs apparently wild in
England in ditches, ponds, &c., is supposed to have been introduced.
AROLSEN, a town of Germany, capital of the principality of Waldeck, 25
m. N.W. of Cassel, with which it is connected by rail via Warburg. Pop.