Part 22

=The Greater Dodder= (Cuscuta europæa).

There are two Dodders indigenous to this country, and we have the misfortune to have introduced a third with flax-seed from abroad. The one figured is the Greater Dodder, which is usually found clinging in a tangle round the stems of nettles, oats, thistles, vetches, etc. This close embrace is sinister in character, for, as may be guessed from the entire absence of leaves and green-colouring matter, the plant is a parasite. Its stem is a mere thread, varying from red to yellow in hue, and having at frequent intervals bunches of reddish flowers. These are very small, but if separated will be found to consist of a four- or five-parted calyx, a persistent pitcher-shaped corolla of similar parts, and stamens to match. Styles two, entirely within the flower. This species is not found north of Yorkshire, and is everywhere rare. It flowers from July to September. The common species, to be found growing on thyme, heather, and furze, is,--

The Lesser Dodder (C. epithymum), with finer stems of a more crimson tint, and the styles protruding. There is a variety of this which confines its attention to the clover plant, and has, in consequence, been raised to the dignity of a separate species by some authors (C. trifolii). In addition there is the Flax-dodder (C. epilinum), previously alluded to as having been introduced from the Continent with flax-seed.

Owing to the serious nature of the attacks of this foreign invader upon our flax-crops Professor Buckman was induced years ago to experiment, with the object of elucidating its mode of growth. He found that seeds of Dodder sown strictly apart from any host-plants germinated in four days, and on the sixth a thread-like plant was seeking a foster-parent, but by the eighth, not having succeeded in its object, it died. Others were sown in company with flax-seed, and in a few days the young dodders attached themselves to the young flax-plants, made one or two tight coils round the victims, whose growth soon lifted the dodders right out of the soil, and thereupon the parasites sent aerial roots into the flax, and their natural roots dwindled and perished. Thereafter its true parasitical growth is most rapid, to the detriment of the foster plant.

The genus is included in the Natural Order Convolvulaceæ.

=Corn Cockle= (Githago segetum). Plate 72.

Wandering through or round the cornfields any time from June to September we are almost sure to find this beautiful flower. It is first cousin to the Lychnis, already described, and in general structure agrees with it, only differing from it in having a leathery calyx, and in the absence of the crown of little scales which surround the mouth of the corolla-tube in Lychnis. They produce honey, but owing to the length of the tube it is only accessible to the long tongues of butterflies and moths, who are instrumental in effecting its cross-fertilization. The plant is an annual, with erect branching stem, clothed with white hairs. The leaves are long and narrow, four or five inches long. The woolly calyx is in one, strongly ribbed, with five very long leaf-like teeth, that considerably exceed the petals in length. The flowers are purple, and measure nearly two inches across.

This is the only native species; indeed, some writers consider it to be only an introduced plant--a form of Agrostemma gracilis that has been altered by its continuous growth in our cultivated fields.

Cuscuta europæa.

--CONVOLVULACEÆ.--]

Githago segetum.

--CARYOPHYLLEÆ.--]

=Purple Medick or Lucerne= (Medicago sativa). Plate 73.

Though the rambler will find this handsome plant growing apparently wild in the hedgerow and on the borders of fields, he must not too hastily conclude it is a native. The species has been largely grown here as a green fodder plant, for which it is highly esteemed, and it has escaped from the fields and reproduced itself without man’s aid. A glance at its flowers will show it is a leguminous plant. Its stems are hollow, branched; its leaves trifoliate, with long-pointed stipules at the base of the leaf-stalk. From the axils of the leaves arise long stalks, whose free ends are crowded with the deep purple (sometimes yellow) flowers. A peculiarity of this genus consists in the seed pod being more or less spirally twisted. In the present species it is downy and has two or three coils. It flowers from May to July.

It has been thought to be a cultivated variety of the next species, M. falcata. The name Medicago is from the old Greek medike, so-called because it was introduced into Greece by the Medes. The following species also occur in this country:--

I. Yellow Sickle Medick (M. falcata), with yellow (sometimes violet) flowers, and a flat downy pod coiled in the shape of a sickle or a ring. Dry gravelly banks, old walls and sandy wastes in the Eastern Counties. June and July. This and M. sativa are perennials; the following are annuals:--

II. Black Medick or Nonsuch (M. lupulina). So much like Trifolium procumbens, described on p. 49, that farmers have given it the name of Hop-Trefoil, which properly belongs to the latter species, from which this may be easily separated by noting that the black kidney-shaped pods are naked, that is, not wrapped in the dried flower. It should also be observed that the pods are marked by prominent veins running throughout their length. Flowers small, crowded, yellow. Waste grounds and cultivated fields. May to August.

III. Reticulated Medick (M. denticulata). Stems creeping. Leaflets heart-shaped, toothed. Flowers yellow, in umbels. Pod beautifully covered with network of veins; broad, flat, and coiled into a spiral; edges with double row of spines. South and Eastern Counties, and Ireland. May to August.

IV. Spotted Medick (M. maculata). Similar to last, but pod more globose, network faint, the spines long and curved. Leaflets often with black spot in centre. Leaf-stalk hairy. Gravelly pastures and hedgebanks in England and South Ireland. May to August.

=Yellow Iris or Flag= (Iris pseudacorus). Plate 74.

Fringing our rivers, ditches and lakes, the Yellow Iris appears to be defending them with drawn sword. Everybody knows the sharp-edged leaves of this species, that may cut the hands of the gatherer if he be not careful. Equally well-known are the bright blossoms that begin to appear in May and keep up a succession until late in July; but probably most of the unscientific readers who have honoured me with their company thus far--and who have learned, I trust, to know the parts of a flower at sight--would be incorrect in their description of this common flower. Anyway, it will be worth their while dissecting a flower. The parts of the flower are in threes, but the sepals are more petal-like than the petals, and so are the styles. The sepals are in fact the most striking organs; they are broad, and reflexed to form convenient alighting platforms for a heavy humble-bee. The petals are narrow, erect, or curved towards the centre of the flower, to be out of the way of the broader, arching style, which is spread out and coloured like a petal, with the stigmatic surface near the upturned tips. Beneath this arching style lies the anther, similarly curved, and opening away from the stigma.

Note the why and wherefore of this departure from orthodox arrangements of floral organs. At the bottom of the flower-tube honey is secreted, and to obtain this the flower is visited by humble-bees. In order that his long tongue may reach the honey, the bee has to push his head and back against the stigma and the anther. If he has previously visited a flag-flower his back will be covered with pollen, some of which will adhere to the stigma. He will also take away on his head and back some of the pollen from the flower he is now visiting, and will fertilize other flags with it.

There is another British species,--

The Stinking Iris, Gladdon, or Roast-beef plant (Iris fœtidissima), with purple sepals, yellow petals and stigmas. Flowers not quite so large as the last. Woods and copses. May to July.

Medicago sativa.

--LEGUMINOSÆ.--]

Iris pseudacorus.

--IRIDEÆ.--]