The Dog's Mercury grows abundantly in England and Scotland but is rare in Ireland. You find it during early spring in woods and shady places and thickets.

This is one of our green flowers. It has no beautiful coloured petals to attract the bees or insects.

The Dog's Mercury is a bushy, upright plant, with a stout, four-sided green stem, closely covered with pretty leaves.

These leaves grow in pairs, on alternate sides of the stem: they are oval, and slightly hairy, and the edges are cut all round into sharp teeth.

Where each leaf joins the stem a flower-stalk rises, and in the Dog's Mercury there are two kinds of flowers. On one stalk you find groups of small flowers cl.u.s.tered at close intervals round the stalk. Each of these flowers has three broadly pointed green sepals, which curl slightly at the tips. In the centre of these sepals rises a large bunch of eight to sixteen yellow-headed stamens. In these flowers there are no petals, and no seed-vessel.

But you will find different flowers on another plant. These flowers have also three green sepals, and are without petals. But in the centre lie two hairy green seed-vessels, like small peas joined together, and on the top of these seed-vessels are two tiny green horns.

3. COMMON NETTLE

What child does not know the Common Stinging Nettle? We have all learned to avoid it after having felt its sting.

You find this Nettle everywhere in late summer and autumn.

It has a four-sided stem, which is rough with bristly hairs. The leaves grow opposite each other in pairs with a good s.p.a.ce between each pair.

They are dark green and rather coa.r.s.e, and are covered with a network of veins and with many stinging hairs.

Close to the stalk the leaves are heart-shaped, but the tips are sharply pointed and the edges are deeply toothed all round.

The flowers of the Common Nettle grow on slender stalks which rise between the leaf and the main stem. These flowers are green, and they are very small and unattractive.

On one flower you find four green sepals and four yellow-headed stamens, but there are no petals and no seed-vessel.

In another flower there is a fat green seed-vessel, with four sepals round it.

PLATE x.x.xI: 1. PURPLE SEA ROCKET 2. CUCKOO FLOWER OR LADY'S SMOCK 3. MARSH CINQUEFOIL 4. WATER AVENS

1. PURPLE SEA-ROCKET

The Purple Sea-Rocket grows abundantly all summer on most of our seash.o.r.es. It is a bushy plant with many branches, and you will recognise it by its thick and fleshy green leaves. The flowers are a pale lilac colour, like those of the Cuckoo Flower. Some of them grow on heads at the end of the main stem, and others have short stalks which branch from each side of this stem.

In this plant there are always buds in a cl.u.s.ter at the end of the stem, and those flowers that come out first grow further down the stem.

Behind the lilac flowers there are four small brownish-green sepals.

When these fall off, after the flower is withered, the seed-vessel which lies inside grows into a small green pod. The pod is in two pieces and looks as if it were joined in the middle. You will see a great many of these tiny pods growing on each side of the main stalk where there have been flowers.

The stem of the Sea-Rocket is very smooth and juicy. The leaves are long and feather-shaped, and they are cut very irregularly into fingers all the way round.

2. CUCKOO FLOWER OR LADY'S SMOCK

The Cuckoo Flower is very common and grows all springtime in every meadow.

The flowers are a pale purple or lilac. Sometimes you find them almost white. They have four petals, each of which has a slight nick in the outer edge. There are six stamens with yellow heads, which you can just see in the centre of the flower where the petals meet; and you will notice that two of these stamens are much shorter than the others.

The flowers grow in a cl.u.s.ter near the end of a stout stalk. After the petals and the small green sepals fall off, the seed-vessel, which is in the middle of the stamens, shoots up into a long thin pod. This pod is slightly curved, and is pale brown.

The leaves of the Cuckoo Flower are of two kinds. Those that spring from the root, close to the ground, grow opposite each other in pairs of leaflets, on a stalk which has an odd leaflet at the end.

But the leaves which appear further up the main stem are quite different They, too, grow in opposite pairs, but they are long and narrow like pointed straps, and are not nearly so pretty as those which are closer to the ground.

3. MARSH CINQUEFOIL

The Marsh Cinquefoil is not so common as many plants. It likes best to grow where there are high hills, and you find it all summer in wet ground among the peat-bogs.

It has black roots, which creep a long distance among the mud, and from these roots grow beautifully shaped green leaves, and rather strange-looking flowers.

These flowers have five small petals, which are a deep purple colour. So are the stamens, so are the seed-vessels. Even the sepals, which are bigger and longer than the petals, are a rich, dark purple, except at the foot where they join the stalk, and there they are greenish.

The Marsh Cinquefoil has two rings of sepals. Those in the outermost circle are shaped like a narrow tongue. The inner sepals are much broader, and they end in sharp points.

The flowers have each a stalk which branches from the main stem.

Sometimes two flower-stalks will spring from the same part of the stem, and in that case there will be a large green leaf clasping the stem where they rise.

These leaves are usually divided into three fingers, each of which is long and rather narrow, with sharp teeth all round. There are a few hairs on the upper side of the leaf, but underneath it is quite smooth.

4. WATER AVENS

The Water Avens loves moist places, and in summer you find it abundantly by the sides of ditches and streams.

It is a delightful plant to discover, as both the leaves and the flowers are beautiful.

The flowers grow singly at the end of slender stalks which branch from the main stem near the top. They are cup-shaped, with heads that are always drooping.

The petals are bright orange-brown, tinged with purple, and outside these brilliant petals there is a calyx of deep purple sepals. These sepals are lined with bright green and have pointed tips, and there are many hairs all over them.

In the centre of the flower are bright yellow-headed stamens, and when the flower is withered, and the seeds begin to ripen, a short green stalk rises in the middle, and on this there appears what looks like a small green strawberry. From every seed on the strawberry there grows a long spike with a curl in the middle. This spiky seed-vessel is very curious.

The leaves of the Water Avens are deep green, and sometimes they have red streaks round the edges as well as on the back. They grow in pairs on the leaf-stalk, a large pair and a small pair alternately, and they are slightly hairy, with edges which are nicked all round. Where the leaves join the main stem there is often a tiny scale.

PLATE x.x.xII: 1. DOG VIOLET. 2. HEARTSEASE. 3. COMMON MALLOW.

1. DOG VIOLET

The Dog Violet begins to flower early in summer. You find it growing on banks under the hedges, a tiny plant with flowers so small and stalks so short that the flowers are of no use after you pluck them.

Every child knows what a violet is like, but you should pick one of the flowers to pieces and see how curiously each petal is shaped. There are five petals, and these petals are pale purple at the broad part, but at the narrow end they are almost pure white, and this narrow end is hidden among the green sepals. Four of these petals are nearly the same size, and on two of them there are patches of hair near the foot.

The fifth petal is much larger, and the narrow end of this broad petal is shaped like a round tube. This tube, instead of being hidden among the sepals, stands out beyond them like a spur. Inside the tube are the stamens, and all the yellow heads of the stamens are joined edge to edge in a ring round the seed-vessel.

The Dog Violet has five green sepals with very sharp points, and the lower part of each sepal is slightly swollen. The leaves are heart-shaped, with toothed edges, and they grow very close to the ground and have scarcely any stalks. This Violet has no scent.