Part 37

On roadside banks, particularly in chalky districts, we may often meet with the Wild Parsnip (Pastinaca sativa). This is an erect, downy plant, with a tap root; and angular, hollow stem from two to three feet high. Its leaves are pinnate, glossy above and downy beneath, with five or seven ovate, sessile, cut and serrate leaflets, and sheathing petioles. The umbels are terminal, without primary or secondary bracts; and the flowers are small, of a bright yellow colour, producing flattened, winged fruits. The flowers bloom during July and August.

The Cow Parsnip or Hogweed (Heracleum Sphondylium) is somewhat similar in general appearance, but is much stouter, and grows to a height of four or five feet. Its stem is hairy and channelled; and the leaves have a few broad, lobed, serrate leaflets with a rough, hairy surface. The flowers, which bloom during July and August, are of a reddish white colour, and have unequal petals.

The Upright Hedge Parsley (Torilis Anthriscus or Caucalis Anthriscus) is a slender plant, with an erect, solid, rough stem, from two to three feet high. Its leaves are hairy, bipinnate, with lobed and toothed, ovate or oblong leaflets. The white or pale pink flowers are arranged in long-stalked, terminal umbels of from about six to twelve rays, with several primary and secondary bracts. The fruits are armed with bristles which, though not hooked, are slightly bent inwards. This is a very common hedgerow plant, flowering from July to September.

Our last example of the Umbelliferæ is the Rough Chervil (Chærophyllum temulum), which is very common in hedgerows, among the undergrowth of woods, and in other shady places. It has a slender stem, from one to three feet high, swollen at the joints, spotted with purple, and rendered rough by short hairs. The leaves, which are also rough and spotted, are bipinnate, with ovate leaflets that are cut into segments terminating abruptly in a sharp point; and they assume a rich purple tint that makes the plant a conspicuous object in the autumn. The flowers are white, in terminal compound umbels which droop in the bud. The bracts are few in number or altogether absent, but there are several secondary bracts which are fringed and bent downwards.

Passing now to the order Caprifoliaceæ, we have to deal with the well-known and favourite Honeysuckle or Woodbine (Lonicera periclymenum), so highly prized on account of its lovely fragrant flowers. It is a climbing plant, often reaching a height of ten or twelve feet, supporting itself by twining its woody stem round surrounding shrubs and trees in hedges and the open spaces of woods. The beautiful flowers, which are yellow within, and more or less tinged with red outside, are arranged in terminal, stalked heads; and the united petals form widely-gaping lips. The plant blooms from June to September, and displays its crimson berries in the autumn.

Two other species of Honeysuckle occur in our hedges, but neither of these is common. One is the Upright Honeysuckle, which has an erect stem; downy, stalked leaves; and pale yellow, scentless flowers that grow in pairs in the axils of the leaves. The other is the Perfoliate Honeysuckle, so called because its upper leaves are united at their bases, with the stem running through them. In this one the flower-heads have no stalks.

In the Bedstraw family (order Rubiaceæ) we have two very common, hedgerow plants--the Great Hedge Bedstraw (Galium Mollugo) and the Goose-grass or Cleavers (G. Aparine). The first is a very straggling plant, with a square stem, thickened at the joints, that often reaches a length of four or five feet. Its leaves are elliptical, with apex terminating suddenly in a bristle-like point, and margins roughened by prickles that are either at right angles or pointing more or less forward. They are arranged in whorls, usually of eight, but sometimes six. The little white flowers, which bloom during July and August, are arranged in panicles with spreading branches, the lower of which are either horizontal or bent downward. The fruit is smooth.

The Goose Grass is so named because it is eaten by geese; and it is also known as the Cleavers because its fruits, which are covered with hooked bristles, cling tenaciously to our clothing and to the covering of animals. Its straggling stem often reaches a length of four or five feet, and forms tangled masses with the stems and leaves of other hedgerow plants. The leaves are narrow and keeled; and the small, white flowers are arranged in small axillary clusters of two or three. The whole plant is rough with hooked bristles.

We conclude this chapter with a description of the common Teasel (Dipsacus sylvestris) of the order Dipsaceæ. This is really a very graceful plant, rarely less than three or four feet high, and sometimes reaching six feet or more. Its stem is very stout and prickly; and its large bright green leaves are simple, sessile, and arranged in opposite pairs. They are prickly beneath, and the two leaves of each pair are united at their bases in such a manner that they form hollows in which the rain-water collects. The reservoirs so formed often contain drowned insects which have flown or fallen into the water, or which have been washed down the stem by the rain. Their dead bodies decompose, giving rise to nitrogenous and other products of decay which generally discolour the water. These products are valuable as plant food, and it has been said that they are absorbed by the leaves. The flowers of the Teasel are collected in large heads, covered with straight, stiff bristles, and have an involucre of bracts which curve upwards. The flowers are of a pale purple colour. They commence to open near the middle of the head, forming a horizontal circle; and then they expand both upwards and downwards from this level. The flowers are not conspicuous individually, nor does each individual flower produce much pollen; but the large heads of bloom attract numerous insects which climb about among the flowers in search of nectar, covering their bodies with pollen, and thus aiding the process of fertilisation.

XII

WAYSIDES AND WASTES IN SUMMER (Continued)

COMPOSITE FLOWERS

There are so many flowers of the order Compositæ in bloom by the wayside and on waste ground during the summer months that we devote a chapter entirely to them.

This group is the largest of the natural orders, and is computed to contain about a tenth of all the known flowering plants. The chief distinguishing characteristic of the order is the arrangement of the flowers into crowded heads, each consisting of a number of little flowers or florets that are sessile on a common receptacle, as in the case of the Daisy, the Dandelion, and the Thistles.

The florets of each head or capitulum are generally arranged into two well-defined sets--the florets of the disc, occupying the centre; and the florets of the ray, spreading more or less in a radial manner from the edge of the disc. These two sets are often of different colours, as in the Daisy, where the disc florets are of a deep yellow, while the ray florets are white or pink.

In some of the Composites all the florets of each head are perfect, while in others some are perfect and some imperfect. Then, as regards the latter, they may be staminate or male florets, with no pistil; pistillate or female flowers, with no stamens; or neuter florets, possessing neither stamens nor pistil. In some few cases all the florets of one head are staminate, while the pistillate florets alone form other heads; and in these instances the two kinds of heads may be found on one plant, or only one kind may exist on the same plant. In all cases the capitulum is surrounded by one or more whorls of bracts which are often closely overlapping.

The florets seldom possess a distinguishable calyx, but there is sometimes an indication of the presence of five sepals; in many, however, the calyx is represented by a whorl of hairs on the summit of the ovary. Such a whorl is known as the pappus, and it frequently enlarges as the fruit ripens, forming a kind of parachute that allows the fruit to be carried great distances by the wind. The hairs of the pappus are often sessile on the fruit, but sometimes mounted on the summit of a slender stalk, as in the Dandelion. Further, the hairs which constitute the pappus may be simple or feathered.

The corolla frequently consists of five petals, united into a tube with as many teeth; but it is often ligulate or strap-shaped, in which case the presence of five petals is often denoted by five minute teeth at the tip.

Where stamens exist they are five in number, attached to the petals, and the anthers are generally united in such a manner that they form a tube within the tube of the corolla.

Fertilisation is brought about much in the same way in many of the composite flowers:--The anthers open inwards, discharging their pollen within the tube formed by themselves, and just above the stigma which, as yet, is immature. The style then lengthens, pushing its way up through the anther-tube, and brushing up the pollen by means of the tufts of hairs on its surface. At this stage a dense cluster of pollen cells, completely covering the top of the style, may be seen projecting above the tube of the corolla, and the pollen is sooner or later scattered, the distribution being aided greatly by the various insects which visit the flowers. The upper part of the style now divides into two parts, and the branches diverge, exposing the stigmatic surfaces which form the inner sides of the fork. It will thus be seen that the florets are not self-pollinated, since the stigma is generally mature after the pollen has all been removed from the same flower.

Our first example of this order is the Yellow Goat's-beard (Tragopogon pratensis), also known as Jack-go-to-bed-at-noon. This is a common wayside plant, of a glaucous green colour, with a milky sap. Its stem is erect, from one to two feet high, and the whole plant is smooth. The flower-heads are solitary, large, yellow, and surrounded by a single row of narrow bracts that are united below; and the peduncle is thickened at the top. The bracts are generally as long as the florets, and the latter usually close about the middle of the day. The fruit is long and narrow, with longitudinal ridges; and the pappus consists of rows of feathery hairs which interlock and form a very shallow cup. The flowers bloom during June and July.

The Bristly Ox-tongue (Helminthia echioides or Picris echioides), also a common plant, is more or less covered with rigid, hooked bristles, each of which arises from a swollen, white base; and it has a milky sap. The stem is stout, branched, very bristly, and grows from two to three feet high. The leaves are simple and toothed, the upper ones cordate and embracing the stem, and the lower ones auricled or eared. The heads are terminal, consisting of yellow, ligulate florets, surrounded by five large cordate bracts. The fruit is brown, curved, with transverse ridges and a stalked pappus of feathery hairs. This species flowers from June to September. It is shown on Plate III.

In the same genus we have the Hawkweed Picris (P. hieracoides) which bears yellow flowers from June to September. Its stem, more slender than that of the last species, is from two to three feet high, branched towards the top, and rough with hooked bristles; and the leaves are lanceolate and toothed. There are numerous heads of flowers, about an inch in diameter, usually arranged in a corymb, but sometimes in an umbel, and there are bracts on the peduncles.

The Strong-scented or Acrid Lettuce (Lactuca virosa) is moderately common on dry wastes. It is an acrid, glaucous, leafy and prickly plant, with a milky juice. Its erect stem grows to a height of three or four feet. Its leaves are spreading, obovate in form, with toothed margins, and bristly hairs on the under side of the midrib. The lower leaves are frequently marked with dark spots, and the upper ones have pointed auricles which clasp the stem. The heads of flowers are small, pale yellow, and arranged in a loose, spreading panicle. The bracts overlap, the outer ones being shorter, and the receptacle is flat. Each head contains only a few florets. The fruit is flattened, black, with a beak as long as itself and a pappus of many simple hairs. The flowers appear during July and August.

Another Lettuce, known as the Prickly Lettuce (L. Scariola), is somewhat rare. It is really less prickly than the last species, but is equally tall, and flowers during the same months. Its leaves are erect, lanceolate, sagittate, with a wavy margin; and the upper ones clasp the stem. The fruit of this species is of a greyish colour, and has a beak of the same length.

Two species of Sow-thistle (genus Sonchus) are included among our wayside Composites. They are erect, succulent plants, from two to three feet in height, with a milky juice, and either toothed or pinnatifid leaves. Their flower-heads are yellow, arranged in a corymb, and bloom during the whole of the summer. Each head is surrounded by several rows of overlapping bracts, and the receptacle is flat and pitted. The fruits are considerably flattened, without beaks; and the pappus consists of several rows of fine, silky, unbranched hairs.

One species is known as the Sharp-fringed Sow-thistle or the Common Milk-thistle (S. oleraceus). Its leaves are sometimes deeply divided, but always more or less toothed; and the teeth often terminate in sharp prickles. The upper ones clasp the stem, and have spreading, arrow-shaped ears. The stem is branched and hollow; and the fruit is ribbed and transversely wrinkled.

The second is the Common Sow-thistle (S. asper)--a very similar plant, but may be distinguished by its leaves, which are more spinously toothed, with rounded ears. In this one the fruits are also ribbed, but they are not wrinkled transversely.