While some flowers are so universally distributed that they may be described as existing almost everywhere, others are restricted to certain kinds of localities, outside which they seldom occur. This restriction is sometimes merely one of light and shade, the same species growing almost equally luxuriantly in open spaces, or, in shady places, regardless of other conditions. Some plants, however, are particularly partial to certain conditions of soil, situation, or climate, and are consequently more strictly confined to limited districts.

We have already referred to several species which are essentially flowers of the woods, but even these are not distributed evenly in wooded districts; for while some seem to be more universally scattered throughout our wooded parts, others show a decided partiality to particular soils, being found exclusively, or almost so, either in sandy woods, clayey woods, or woods in limestone districts, &c. In fact, the nature of the soil is such an important factor in determining plant distribution that we naturally associate many species with the particular rock strata on which we almost invariably find them.

So intimately is the distribution of plants connected with that of the geological strata that when, in the course of a day's ramble, we find a more or less sudden change in the nature of the flora, we may be almost sure that there is a corresponding change in the nature of the rocks or soil over which we have strayed; and the young botanist will find much to interest him in the study of this relation between vegetable life and geological structure. Of course we do not mean that the botanist must necessarily be also a geologist, but that he should, at least, be always ready to observe the nature of the habitats of the flowers he finds, noting particularly the kind of soil on which they grow.

Chalky districts are notably attractive to the lover of flowers; for, not only do they yield a number of species that are almost essentially the offspring of calcareous soils, but also produce other blossoms, often in rich profusion, that are less restricted in their habitats.

In the present chapter we shall note the principal flowers that grow principally or entirely in calcareous districts, the first being the Pasque Flower (Anemone Pulsatilla—order RanunculaceÆ), rare, it is true, but too beautiful to be omitted from our selection. This flower, shown on Plate VIII, Fig. 5, may be seen on some chalky hills during May and June. It is of a silky nature, and the lovely purple blossoms often reach a diameter of an inch and a half. The leaves are doubly or trebly pinnate, with very narrow segments which increase in length after the flowers have faded. The bracts, which are some distance below the flower, have also linear segments; and the flowers droop while still in the bud, but the peduncle becomes erect as they expand. The stamens are yellow, and the fruits are provided with feathered hairs.

On chalky, sandy, and other dry soils we may meet with the Round Prickly-headed Poppy (Papaver hybridum—order PapaveraceÆ), very much like the Common Poppy in general appearance, but readily distinguished by its general hairy character, and, more especially, by the globular, furrowed fruit covered with spreading bristles. The flowers vary from one to two inches in diameter, and the crimson or deep scarlet petals are often black at the base.

The Bitter Candytuft (Iberis amara—order CruciferÆ), which is so well known as a border-flower of our gardens, grows freely in some of the chalk districts of the South and East of England. Unlike most of the Crucifers, the flowers are not symmetrical, the two outer petals being much larger than the others. The inflorescence is a raceme, which, like that of the Wallflower, becomes longer as the flowering proceeds; and the colour of the petals is white, lilac or red. The height of this plant varies from six to nine inches, and the flowers bloom during July and August.

The Wild Mignonette (Reseda lutea—order ResedaceÆ) is very common in some chalky districts, generally in fields and other open ground, and may be easily recognised by its close resemblance to the well-known Sweet Mignonette (R. odorata), which is so highly valued as a garden flower on account of its pleasant perfume. It is of a shrubby nature, from one to two feet high, with scattered, stipuled leaves, the lower of which are pinnate, while the upper are three-lobed. The flowers are irregular, yellow, and arranged in short, conical racemes. The six sepals are unequal and linear; and the petals, also six in number, are very unequal, while the posterior one is divided into many parts. The flowers bloom throughout the summer.

One of the most characteristic flowers of the chalk is the pretty Rock Rose (Helianthemum vulgare—order CistaceÆ), which is often so abundant that it completely covers large patches of banks and pasture-land. The plant is of a procumbent nature, with woody stems, and opposite, flat, oval or oblong leaves, green above and hoary beneath. The yellow flowers are from three-quarters to an inch in diameter, and are arranged in racemes. There are five sepals, two of which are very small; and the numerous stamens are sensitive, spreading out and lying on the petals when the flower is squeezed. The time of flowering is from June to September.

An allied species—the Hoary Rock Rose (H. canum or H. marifolium)—may be found in the limestone districts of the West of England, flowering from May to July. The plant is very similar to the last, but the leaves are not stipuled, are smooth or hairy above, and very hoary beneath. The flowers, too, are much smaller.

A species of Violet—the Hairy Violet (Viola hirta—order ViolaceÆ)—may be found in some limestone and chalk districts, and also on some dry soils removed from calcareous rocks. It has no runners like those of other species, and its cordate leaves are very hairy, on petioles covered with spreading hairs. The flowers are scentless, pale violet or white, with bracts below the middle of the peduncle; and the spur of the corolla is long, blunt, flattened, and hooked.

Two species of Flax (order LinaceÆ) are to be found on chalky soils. One—the Perennial Flax (Linum perenne)—grows in hilly districts, but is not at all common. It is a slender plant, with numerous wiry stems from one to two feet high; and sessile, linear, acute leaves. The petals are of a beautiful sky-blue colour, but so lightly attached that it is difficult to secure a perfect specimen. The other species—the Narrow-leaved Flax (L. angustifolium)—is moderately common on calcareous hills of the South and West of England. It is very similar to the last, and grows to about the same height, but its many stems are more irregularly branched, and the alternate leaves are linear-lanceolate. The corolla is of a lighter lilac-blue colour. L. perenne blooms during June and July, and the narrow-leaved species from June to September. The latter is shown on Plate VIII.

Quite a number of species of leguminous plants (order LeguminosÆ), may, as a rule, be met with on dry soils, but only two common ones may be described as particularly partial to chalk and limestone localities. These are the Tufted Horse-shoe Vetch (Hippocrepis comosa) and the Sainfoin or Cock's-head (Onobrychis sativa). The former, represented on Plate VIII, is a low, smooth, prostrate plant, six to eighteen inches long, with yellow flowers that bloom from May to August. This plant is sometimes confused with the Bird's-foot Trefoil, which it rather closely resembles in general appearance, but it may be readily distinguished by the pinnate leaves and the peculiar form of the pods. The latter are flattened, and break up, when ripe, into from three to six one-seeded, horse-shoe-shaped segments—a feature which has given rise to the popular name.

The Sainfoin is often cultivated in the South-East of England as fodder for cattle, but may frequently be found growing wild. It is a very pretty, erect plant, from one to two feet high, with dense racemes of rosy-red flowers beautifully striped with a darker tint. The stem is stout and downy, and the pinnate leaves have membranous stipules and numerous oblong leaflets which terminate abruptly in a point. The pod is compressed, semicircular in form, indehiscent, and toothed along the lower edge. This species flowers during June and July.

On some chalky heaths the True Sweet-briar (Rosa rubiginosa—order RosaceÆ) is a common shrub, growing from three to six feet high, and flowering during June and July. It is an erect and compact bush, with numerous prickles of varying shapes—the larger ones being hooked, while the smaller are straight and very unequal. The leaves are compound and stipuled, and the leaflets are rounded at the base, downy, and doubly serrate. The flowers often grow singly, but more commonly from two to four together; they are of a deep rose colour, and the persistent sepals are pinnately divided. The fruit is at first pear-shaped, but afterwards becomes almost globular, and turns red when ripe.

In similar situations we may find the Lesser Burnet or Salad Burnet (Poterium Sanguisorba) of the same order. This plant is so different in general appearance from the majority of the Rose family that the amateur would hardly associate it with the others. The flowers are small, and collected together in dense, purple cymes on the top of long, angular stalks. They have no petals, and the four overlapping sepals are usually deciduous. The stamens, five to thirty in number, are pendulous on long, slender filaments; and the upper flowers display their crimson stigmas before the lower ones produce their stamens. The stem is erect, from six to eighteen inches in height; and the pinnate leaves have many small, sessile, oblong leaflets with coarsely-serrate edges. This plant flowers during June, July, and August.

The Bedstraw Family (order RubiaceÆ) is represented on the chalk by the Rough-fruited Corn Bedstraw (Galium tricorne), which is common in fields. It is a spreading plant, with procumbent stems, one to three feet long; and small, long, narrow leaves, rough with recurved prickles, arranged in whorls of from six to eight. The flowers are small and white, grouped in little cymes of three. The fruit is comparatively large, and granulated, but not bristly, and it droops by the bending of the pedicel. The plant flowers from June to October.

The Red Spur Valerian (Centranthus ruber—order ValerianaceÆ) is a glaucous, leafy plant (see Plate VIII), sometimes growing to a height of two feet or more, often to be seen in chalk-pits and limestone quarries, and frequently on old walls. It is not indigenous, but is cultivated largely as a garden flower, and has now become naturalised. Its corolla, which is sometimes white, has five unequal lobes, a long, flattened tube, and a slender spur. The plant flowers from June to September.

Of the Composite flowers we shall note two species, the first being the Woolly-headed Plume-thistle (Carduus eriophorus), common in chalky fields, where it throws up its large, cottony heads to a height of from three to five feet during July and August. In order to distinguish it from other similar thistles we must note that its stem is not winged, and that the deeply-divided leaves, with bifid lobes, half clasp the stem at the base; also that the involucre bracts are lanceolate, with long, reflexed spines. The heads of this thistle are of a pale purple colour, of a globular form, two to three inches in diameter, and covered with a thick, cottony growth.

Our other example of the Composite flowers is the Ploughman's Spikenard (Inula Conyza), which is common on chalky banks and pastures, flowering from July to September. It is an erect, downy plant, from two to five feet high, with oval, lanceolate, downy leaves of a dull green colour. The upper leaves are entire and sessile, while the lower are toothed and stalked. The numerous flower heads are of a dull yellow colour, with leaflike bracts, arranged in a branched corymb. The involucre bracts are linear and reflexed, and the ray florets are inconspicuous.

Two representatives of the order GentianaceÆ are commonly found on chalk hills and pastures; they are the Field Gentian (Gentiana campestris), and the Perfoliate Yellow-wort (Chlora perfoliata, or Blackstonia perfoliata). The former is an erect plant, from four to ten inches high, with a branched stem; opposite, sessile leaves; and conspicuous, bluish-purple flowers, blooming in August and September. The calyx is cleft into four, the two outer segments being large and ovate. The corolla is also four-cleft, and salver-shaped.

The Yellow-wort is an erect, glaucous plant, with an unbranched stem from six to eighteen inches in height, and beautiful yellow flowers, from four to nine in number, arranged in a cyme. The leaves are in widely-separated pairs, united at their bases, so that the stem penetrates them. The calyx is deeply divided, and the limbs of the corolla are spreading. This plant flowers from June to September.

Some species of Mullein (Verbascum) are particularly partial to chalk and limestone districts. They are handsome plants, belonging to the order ScrophulariaceÆ, rendered conspicuous by their woolly leaves and spikes of yellow or white flowers. The Great Mullein (V. Thapsus) is common on banks and roadsides, and flowers from June to August. Its stem is stout, erect, very woolly, and varies from two to five feet in height. The leaves are very large and thick, and are so woolly on both sides that they resemble flannel. The flowers form a large, dense, club-shaped spike. Each has a corolla with five spreading lobes; and five stamens, with white hairs on their filaments, two longer than the other three. The fruit is a capsule containing many seeds and splitting longitudinally.

The White Mullein (V. Lychnitis) is not at all common, but may be found in similar situations. Its stem is angular, seldom more than three feet high, the leaves nearly smooth above, and the flowers white or cream, blooming from June to August.

A third species—the Yellow Hoary Mullein (V. pulverulentum)—grows on banks, chiefly in Norfolk and Suffolk, flowering during July and August. It is about three feet in height; the stem is round, with a mealy surface; and the leaves, which are not continued down the stem, are covered both above and below with starlike hairs that give them a mealy appearance. The flowers form a pyramidal panicle, and are of a bright yellow colour, with scarlet stamens covered with white hairs.

There is yet another species to be found on chalky soils, more especially in hedges and on banks and roadsides. It is the Dark Mullein (V. nigrum), so called on account of the darker hue of the stem and leaves. It grows to a height of about three feet and flowers from June to September. It is a beautiful plant, not so strong in build as the Great Mullein, with an angular stem, and oblong heart-shaped leaves, nearly smooth above, and covered with starlike hairs which give it a downy appearance, especially on the under surface. The leaves are not continued down the stem, and the lower ones have long stalks. The flowers are bright yellow, very numerous, and form a spike-like panicle. The stamens are covered with purple hairs.

The Spiked Speedwell (Veronica spicata), of the same order, neither common nor widely distributed, is to be found chiefly in the chalk and limestone districts of the South and West of England, flowering during July and August. It has a long, dense, terminal spike of blue or pink flowers about a quarter of an inch in diameter. The corolla has a long tube, and unequal, narrow lobes; and the flattened capsules split into two valves when ripe. A large variety of this species, known as the Tall Spiked Speedwell, occurs in limestone districts of the West. The normal form is shown in Fig. 4, of Plate VIII.

Of the Labiates perhaps the one most partial to the chalk is the Wild Sage or Clary (Salvia Verbenaca); and even this is not confined to calcareous soils, but thrives in dry pastures in many parts of the country, particularly near the sea. It is an aromatic herb, from one to two feet in height, with long spikes of bluish purple flowers that bloom from May to September. The leaves, which are not numerous, are oblong-cordate (the upper ones broadly cordate), blunt, coarsely toothed, and wrinkled. Other Labiates are very similar to this species, but the Clary may be distinguished by its two ovate, cordate bracts at the base of each flower, and by its narrow corolla, which is a little shorter than the calyx.

The Red Hemp-nettle (Galeopsis Ladanum), of the same order, is common in chalky fields. It is about a foot in height, and displays its rose-coloured flowers from July to October. The plant is covered with very soft hairs, and the stem is not swollen at the joints. These two features serve to distinguish the species from the Common Hemp-nettle (G. tetrahit) and the Large-flowered Hemp-nettle (G. versicolor) of the same genus. It should also be noted that the corolla is not really red, as the common name suggests, but rose-coloured, while in G. tetrahit it is purple or white, and in G. versicolor it is yellow. The upper lip of the flower, too, is only slightly notched.

The Viper's Bugloss (Echium vulgare—order BoraginaceÆ) is common on dry soils, especially in calcareous districts, where it is often found close to the sea, even on the beach very near high-water level. It is a very peculiar plant, both stem and leaves being thickly covered with stiff, sharp bristles. The stem is unbranched, from two to three feet high; and the leaves are lanceolate. The flowers are of a bright rose-colour when they first open, and afterwards change to a bright purple-blue; they are arranged in short, lateral, curved, one-sided spikes. Both leaves and flowers droop very rapidly after they have been gathered. This plant flowers from June to August.

Another species of the same genus, known as the Purple Viper's Bugloss (E. Plantagineum), is common in the Channel Islands. It may be distinguished by its branched stem and longer spikes of flowers. The lower leaves, too, are oblong and stalked, while the upper ones are cordate and half clasp the stem.

No doubt the reader is already acquainted with the commoner Plantains (order PlantaginaceÆ), so easily distinguished by their spreading radical leaves, with prominent, parallel ribs, and their dense spikes of greenish flowers. There are five British species, one of which—the Hoary Plantain or Lamb's-tongue (Plantago media) is particularly partial to chalky districts, where it grows in pastures and on dry banks. Its flowering stems grow from three inches to a foot in height, and the flowers bloom from June to September. The leaves are elliptical, either sessile or shortly stalked, and have from five to nine ribs. They lie so closely on the soil that nothing can grow beneath them, and even present the appearance of having been pressed against the ground. They also have a downy surface; and the stalk, where it exists, is flattened. The flowering stem is round, and the spike cylindrical. The calyx is cleft into four, with its segments turned backward; and the sepals are not keeled as they are in some other species. The corolla is tubular, with four spreading limbs; and the cream-coloured anthers are displayed on the tips of long filaments.

We have now to consider several representatives of the OrchidaceÆ, and it will be well here to note the general characters of this remarkable order as a whole. The Orchids have rounded or palmate tuberous roots, a few glossy leaves which sheath the stem, and simple spikes or racemes of flowers, the prevailing colours of which are red, pink, green and white. The sepals, three in number, often partake more of the nature of petals. There are three petals, the lowest one, forming the lower lip of the flower, often prolonged into a spur, and frequently assuming a remarkable form resembling an insect or some other member of the animal creation. The stamens are united to the style, and form with it a solid column, but usually only one produces pollen, and this one commonly consists of one or two club-shaped masses. The ovary is inferior, often twisted so as to invert the flower, and sometimes so long as to be mistaken for a flower stalk. The stigma is hollow, sticky, and situated just in front of the column above mentioned. The fruit is a three-valved capsule, containing many seeds.

Orchids are generally scented flowers, and produce nectar which is stored either in the cavity of the spur, or within the tissue of the same. In the latter case it cannot be obtained by insects unless they bore into the substance of the spur, and the delay caused renders the removal of the pollen more certain. While the nectar is being withdrawn, the head of the insect is pressed against a sticky disc at the base of the pollen masses, with the result that both disc and pollen masses are bodily removed, and the insect leaves the flower with the whole attached to its head. It often happens, too, that the pollen masses bend forward as the insect flies through the air, and thus they are more likely to be pressed against the stigma when another flower is visited. Here, then, is another wonderful contrivance for the purpose of securing cross-fertilisation, and the whole process may be imitated by thrusting the point of a pencil into the spur of a flower which has not been previously visited by an insect, and then inserting the point into the spur of a second flower. It should be noted, also, that the pollen is not all removed by contact with the sticky surface of a stigma against which the pollen masses are pressed, and thus the pollen obtained from one flower will often fertilise several others.

Our first species—the Broad-leaved Helleborine (Epipactis latifolia), is common in hilly woods, where it flowers during July and August. Its single stem grows from one to three feet high, and the leaves are broadly ovate and ribbed. The flowers are greenish, with reddish-purple lips, and are arranged in a long, loose, one-sided raceme. The sepals are ovate, longer than the acute lower lobe of the lip; and the bracts are generally longer than the flowers. The ovary is downy, and not so long as the bracts. (Plate II, Fig. 5.)

The somewhat similar Large White Helleborine (Cephalanthera grandiflora), which bears creamy white flowers in May and June, is also common in some of the woods on calcareous soils.

The Pyramidal Orchis (O. pyramidalis) grows in limestone pastures, flowering during July and August. This species varies from six to eighteen inches in height, and has linear, acute leaves. The spike of flowers is very dense, of a pyramidal form, and the individual blooms are small, usually of a rose colour, but occasionally white or nearly so. The sepals are spreading, and the lip of the flower has three equal lobes which are oblong and abruptly cut at the tips. The spur is slender and longer than the ovary.

The Fragrant Gymnadenia or Sweet-scented Orchis (Habenaria conopsea or Gymnadenia conopsea) is common on chalky heaths and hilly pastures. It grows from twelve to eighteen inches high, has palmate, tuberous roots, and oblong-lanceolate, acute, keeled leaves. The flowers appear from June to August, and are in a dense, elongated spike. The buds are of a deep rose colour, and the open flowers are very fragrant, of a lighter colour, and not spotted. The bracts have three veins; the lateral sepals are spreading; the spur long and slender, much longer than the ovary; and the lip of the flower has three, equal, undivided lobes.

The Sweet-Scented Orchis.