[Ill.u.s.tration: Sycamore.] [Ill.u.s.tration: _Pl. 46._

Leaf-buds of Sycamore.]

[Ill.u.s.tration: _Pl. 47._ Bole of Sycamore.]

Its name of False Plane is due to the Scots calling it the Plane, misled of old by the similarity of the leaves, and the fact that patches of the fine ash-grey bark flake off, as in the true Plane, showing other tints. It grows to a height of sixty or even eighty feet so quickly that it is full-grown when only fifty or sixty years old, though it is supposed to live from a hundred and fifty to two hundred and fifty years. Like that of the Common Maple, the wood of the Sycamore is firm and fine-grained, which does credit to the efforts of the French-polisher. The leaves are more heart-shaped, but cut into five lobes, whose edges are unequally toothed; they are six or eight inches across. The flowers are similar to those of the Common Maple, but larger, and in a long hanging raceme, which has a rather fine appearance. The samaras are scimitar-shaped and red-brown, about an inch and a half long. These are produced freely after the tree is about twenty years old. Like many other Maples, the Sycamore has sap which contains much sugar. Some of this appears also to exude through the leaves, for they are often found to be quite sticky to the touch. The black patches so frequent on Sycamore leaves are the work of a small fungus--_Rhytisma acerinum_.

The Norway Maple (_Acer platanoides_) is a tree of much more recent (1683) introduction from the Continent. Its height is from thirty to sixty feet, and its early growth is very rapid. The leaves are even larger than those of Sycamore, of similar shape, but the lobes are only slightly toothed. The cl.u.s.ters of bright yellow flowers are almost erect; the tree does not produce seed until it is between forty and fifty years old.

The Maple was the Mapel-treow or Mapulder of the Anglo-Saxons; it was originally the Celtic _mapwl_, and the name indicated those knotty excrescences on the trunk from which the cabinet-maker got the mottled wood that was so highly prized in early times for the making of bowls and table-tops, for which fabulous prices have been paid.

[Ill.u.s.tration: _Pl. 48._ Sycamore--winter.]

The Poplars (_Populus_).

Almost everybody who has an elementary acquaintance with trees knows a Poplar at sight, the foliage being so very distinct from that of other trees. But the distinctions between the several species are not so immediately obvious. Five kinds of Poplar are commonly grown in this country, of which only two are regarded as distinct indigenous species.

These are the White Poplar (_Populus alba_), and the Aspen (_P.

tremula_). A third indigenous form, the Grey Poplar (_P. canescens_), is thought to be either a sub-species of _P. alba_, or a hybrid between that species and _P. tremula_. Then of common introduced species we have the Black Poplar (_Populus nigra_), and the Lombardy Poplar (_P.

fastigiata_).

[Ill.u.s.tration: _Pl. 49._ White Poplar, with Catkins--spring.]

The Poplars (_Populus_) and the Willows (_Salix_) together const.i.tute the Natural Order _Salicineae_. The two genera agree broadly in the construction and arrangement of their flowers in catkins, but whereas the Poplars have broad leaves and drooping catkins, the Willows, with few exceptions, have long slender leaves and erect catkins. The s.e.xes are not only in distinct flowers, but on separate trees--what botanists describe by the term _di[oe]cious_. The males appear to be far more numerous than the females. In the popular sense there are no flowers, for there are neither sepals nor petals, each set of s.e.xual organs being protected merely by a scale. The catkins containing these flowers usually appear before the leaves. As there is nothing to attract insects to the work, the trees have to rely upon the wind for conveying the pollen to the female trees. The first three species described below have from four to twelve stamens; _P. nigra_ and _P. fastigiata_ have from twelve to twenty stamens. The Poplars share the love of the Willows for moist places. They are found more frequently in gardens and hedgerows than in woods. Their growth is rapid, and their timber, consequently, is of little value, though its softness and lightness render it suitable for making boxes, and its whiteness and non-liability to splinter fit it for use as flooring. An additional point in favour of White Poplar for the latter purpose is its unreadiness to burn.

[Ill.u.s.tration: White Poplar, or Abele. A, female catkin.]

The White Poplar, or Abele (_Populus alba_), grows into a large tree, something between sixty and a hundred feet high, covered with smooth grey bark. Its branches spread horizontally, and its broad heart-shaped leaves, which vary from an inch to three inches long, are hung on long slender foot-stalks. In most trees the leaf-stalks are flattened from above, but in the case of the Poplars they are flattened from the sides, so that when moved by the wind they flutter laterally. These leaves have a waved margin, a smooth upper surface, and are snowy white and cottony beneath. The leaf-buds are also invested by cottony filaments. The roots produce numerous suckers, even at a distance from the trunk, and the leaves on these sucker-shoots are very large--two to four inches broad--of a more triangular shape, the outline lobed and toothed. The catkins, which appear in March and April, are cylindrical; those of the male trees may be as much as four inches long, each flower containing from six to ten stamens with purple anthers. The female catkins are not nearly so long, the two yellow stigmas are slender with slit tips, and the ovaries develop into slender egg-shaped capsules, each with its fringed scale. This species is said not to produce flowers in Scotland.

In July, when the seed capsules open, the surrounding vegetation and ground are thickly strewn with the long white cotton filaments attached to the seeds. The wood of this tree is softer and more spongy than that of other Poplars.

[Ill.u.s.tration: _Pl. 50._ White Poplar--summer.]

[Ill.u.s.tration: _Pl. 51._ Bole of White Poplar.]

The Grey Poplar (_Populus canescens_), which is thought to be indigenous only in the south-eastern parts of England, is not so tall a tree as _P.

alba_, though it sometimes attains to eighty or ninety feet, with a circ.u.mference between ten and twenty-four feet. Its life extends to about a century, but its wood--which does not split when nails are driven through thin boards of it--is considered best between fifty and sixty years of age. The leaves on the branches are shaped like those of _P. alba_, but their under sides are either coated with grey down or are quite smooth; those of the suckers have their margins cut into angles and teeth. The female flowers mostly have four wedge-shaped purple stigmas (sometimes two), which are cleft into four at their extremities.

[Ill.u.s.tration: Aspen.]

The Aspen or Asp (_Populus tremula_) does not attain either to so large a size or so moderate an age as the Abele. Its height, when full grown, is from forty to eighty feet, and after fifty or sixty years its heart-wood begins to decay, and its destruction is then hastened by the attacks of such internal-feeding insects as the caterpillars of the Goat-moth and the Wood Leopard-moth. The leaves on the branches are broadly egg-shaped, approaching to round, the waved margin cut into teeth with turned-in points. In one form (var. _villosa_) the leaves are covered beneath with silky or cottony hairs; in the other form (var.

_glabra_) they are almost smooth. The leaves on the suckers are heart-shaped, without teeth. The leaf-stalks of the Aspen are longer than those of its congeners, so that they are constantly on the flutter--a circ.u.mstance that has led to an explanatory legend, to the effect that the cross of Calvary was made of Aspen-wood, and that the tree shivers perpetually in remembrance. Possibly the present inferiority of Aspen timber is to be explained in a similar manner. The catkins, which are two or three inches long, are similar to those of the foregoing species, but the scales have jagged edges. It is indigenous in all the British Islands as far north as Orkney, but, though commonly found in copses on a moist light soil, is more frequent as a planted tree in gardens and pleasure grounds. It is a characteristic tree of the plains throughout the Continent, but ascends to 1600 feet in Yorkshire, and in the Bavarian Alps is found as high as 4400 feet. It is not a deep-rooting tree, the root-branches running almost horizontally. Where accessible to cattle or deer, the foliage of the suckers is eagerly browsed by them.

[Ill.u.s.tration: _Pl. 52._ Catkins of Aspen.]

[Ill.u.s.tration: _Pl. 53._ Black Poplar--summer.]

[Ill.u.s.tration: _Pl. 54._ Bole of Black Poplar.]

[Ill.u.s.tration: _Pl. 55._ Black Poplar--winter.]

[Ill.u.s.tration: Black Poplar.]

The Black Poplar (_Populus nigra_) appears to be so called not by reason of any blackness of leaf or bark, but because of the absence of any white or grey down on the underside of its leaves. Its bark is grey, like that of the species already mentioned, but readily distinguished from them by the great swellings and nodosities that mar the symmetry of its trunk. It is a tree of erect growth, fifty to sixty feet in height, with horizontal branches, and leaves that vary in shape from triangular and rhombic to almost circular, and in width from an inch to four inches. They have rounded teeth on the margins, which are at first also fringed, and in their young state the underside is silky. The flowers in the catkins of this and the next species are not so densely packed.

Those of the male are two or three inches in length, and dark red in colour; their abundance before the tree has put out its leaves makes the male tree a conspicuous object. The female catkins are shorter and do not droop. When the roundish capsules burst in May or June to distribute their seeds, the white cotton with which the latter are invested gives prominence to the female tree. The wood is chiefly used by the turner; in Holland, where it is extensively cultivated, it provides the material for sabots. The Black Poplar is not a native of this country, but it is generally distributed throughout Europe and Northern Asia. The date of its introduction is not known, but it has been here for many centuries, and is quite naturalized, springing up on river banks and in other moist situations. Some botanists regard it as only a variety of the Lombardy Poplar, but apart from the very different habit of the tree--not by itself sufficient grounds for separation--there is the more important fact that the Black Poplar rarely produces suckers from its roots, whilst the Lombardy Poplar does so constantly. However, this is a point we can leave for the botanists to discuss; for the purposes of this book the two trees are sufficiently distinct to be treated separately.

The Lombardy Poplar (_Populus fastigiata_) is no more a native of Italy than of England. Its home is in the Taurus and the Himalayas, whence it has spread into Persia. Introduced into Southern Europe, it has become specially abundant along the rivers of Lombardy, and so in France and England it bears the name of that country. Lord Rochford introduced it to England from Turin in 1758. Its leaves are like those of the Black Poplar, but its branches, instead of spreading, all grow straight upwards, so that the fastigiate or spire shape of the tree is produced--a shape only found otherwise among coniferous trees, particularly in the Cypress, the Juniper and the Irish Yew. It is its form, great height (100 to 150 feet), and rapidity of growth that have led to its wide use here as an ornamental tree--in many cases as a mere vegetable h.o.a.rding to shut out some offensive view. Its growth is extremely rapid, especially during its first score of years, when it will attain a height of sixty feet or more, provided it be grown in good, moist (but not marshy) soil. Its wood is, of course, of little value, and is chiefly used for making boxes and packing-cases, where its lightness, combined with toughness and cheapness, is an advantage. The bark is rough and deeply furrowed, unlike the other species, and the trunk is twisted. Like the Black Poplar, it has smooth shoots, and the unopened buds are sticky. It is propagated in this country by suckers and cuttings. It is said that the first trees introduced were so obtained, and that they were all from male trees; consequently, that we have no female trees here, and seed production is impossible. If the female grows here, it is certainly very scarce. The bark has been used for tanning.

[Ill.u.s.tration: _Pl. 56._ Lombardy Poplar--summer.]

[Ill.u.s.tration: _Pl. 57._ Bole of Lombardy Poplar.]

[Ill.u.s.tration: _Pl. 58._ Lombardy Poplar--winter.]

The Black Italian Poplar (_Populus monilifera_) is another misnamed tree, for it is a native of North America, though introduced to England from the Continent in 1772 by Dr. John Hope. It has the distinction of being considered the most rapid-growing even of the Poplars. Loudon gives its rate of growth in the neighbourhood of London as between thirty and forty feet in seven years! Even in Scotland (where it has been largely planted as a subst.i.tute for Larch, since the partial failure of that tree) it attains a height of 120 feet in sixty years, when planted along the river banks. It is probably only a variety of _P.

nigra_, which it resembles in most points, but is larger, and of very erect growth.

The Tacamahac or Balsam Poplar (_Populus balsamifera_) is another importation from North America, introduced in 1692. In its native country it grows to a height of eighty feet, but here forty or fifty feet is more usual. Its leaves are of more slender form than those of the other Poplars, egg-shaped, with a near approach to being lance-shaped. Their edges are toothed, their upper surface dark green and smooth, the underside whitish with cotton. The distinctive character of the tree is the fragrance of its foliage, which scents the air on moist evenings, and makes the Tacamahac a desirable tree to plant near the water, where alone it attains any moderate size.

The Willows (_Salix_).

There is not in the whole of the British flora another genus of plants that presents such difficulties of identification as the genus _Salix_.

Even so hardened a botanist as Sir J. D. Hooker, in reviewing the tangle of species, varieties (natural and cultivated), and hybrids, is so far stirred from his ordinary composure that he stigmatizes it as a "troublesome genus." When Sir Joseph chose that mild adjective he was at Kew surrounded by the national herbaria and with nicely labelled living plants at hand for comparison. What, then, can the rambling nature-lover hope to do with the Willows he comes across one at a time, without much chance of comparing? He must be content to follow the "lumpers," who group a number of these uncertain forms under the name of a species to which they have evident relationship. When he has mastered the distinctions between these aggregate species, it will be early enough to attempt the segregation of the forms and varieties under each.

In their natural condition Willows are graceful and picturesque, but a large number of the examples met with in our rambles have been so altered for commercial reasons as to be more grotesque than beautiful.

It is not the timber-man who is responsible this time, for a pollard Willow, though it produces a shock-head of long slender shoots, suitable for basket-rods, lets in moisture at the top of the bole, and the wood is more or less decayed and worthless. Only four of our native Willows can be regarded as timber trees. These are the White Willow, the Crack Willow, the Bedford Willow, and the Sallow. Like the Poplars, their growth is very rapid, and their wood is consequently light, but it has the advantage of Poplar-wood in being tougher, and therefore serving for purposes where Poplar is of no value. In the present day the growers of straight-boled Willows find their best market among the makers of cricket-bats. A good deal of it is also cut into thin strips for plaiting into chip-hats and hand-baskets. The Osier is grown in extensive riverside beds for the production of long pliant shoots for the basket-weavers; though many of the so-called Osier-rods are really stool-shoots from Willows that have been pollarded, or whose leading shoot has never been allowed to grow. On those parts of our coast where the crab and lobster fishery is pursued, a regular supply of such shoots for weaving into "pots" and "hullies" is a necessity, and a "withy bed"

will usually be found on some valley stream near, or on a damp terrace halfway up the cliffs.

[Ill.u.s.tration: _Pl. 59._ Crack Willow--summer.]

[Ill.u.s.tration: _Pl. 60._ Bole of Crack Willow.]

[Ill.u.s.tration: _Pl. 61._ Crack Willow--winter.]

The bark of the tree Willows has long been known to be rich in an alkaloid called _salicine_, which has tonic and astringent properties, and has often been used instead of _quinine_, though it is not nearly so powerful as the Peruvian drug. The bark is also used for tanning.

The a.s.sociation of the Willow with sadness is very old, but there does not appear to be any satisfactory reason for it--certainly to contemplate a naturally-grown Willow that grows on the edge of a limpid stream, in which its graceful shoots and slender leaves are reflected, does not suggest sad thoughts to the average healthy mind. The a.s.sociation is chiefly with maidens forsaken by their false lovers, as indicated by Shakespeare when he makes Desdemona say--

"My mother had a maid called Barbara: She was in love; and he she loved proved mad, And did forsake her; she had a song of 'Willow'; An old thing 'twas, but it expressed her fortune, And she died singing it."

The Crack Willow or Withy (_Salix fragilis_) is one of the two most considerable of our tree Willows. In good soil it will in twenty years attain nearly its full height, which is eighty or ninety feet. Its bole sometimes has a girth of twenty feet. Its smooth, polished shoots afford the best ready means of distinguishing it, for instead of their base pointing to the centre of the trunk as in other trees, they grow obliquely, so that the shoots frequently cross each other. They are both tough and pliant, but if struck at the base they readily break off. This character explains the names Crack Willow and _fragilis_. The leaves are lance-shaped, three to six inches long, smooth, with glandular teeth, pale or glaucous on the underside, and with half-heart-shaped stipules, which, however, are soon cast off. As we have already indicated under the head of Poplars, the male and female catkins of the Willows are borne by different trees. In the case of the Crack Willow, the male catkins are an inch or two long, proportionately stout, each flower bearing two stamens (occasionally three, four, or five). The female catkin is more slender, the flowers each containing a smooth ovary, ending in a short style that divides into two curved stigmas. The catkins appear in April or May. Although, like most of the Willows, this species is fond of cold, wet soil in low situations, it is not restricted to the plains. In Northumberland it is found at 1300 feet above the sea. Its northward range extends as far as Ross-shire, but it is a doubtful native in both Scotland and Ireland.

[Ill.u.s.tration: Crack Willow.]

The Bedford Willow (_S. russelliana_) is believed to be a hybrid between _S. fragilis_ and _S. alba_. It grows to a height of fifty feet, with a girth of twelve feet. The leaves are more slender than those of _S.

fragilis_, taper to a point at each end, and are very smooth on both sides. It occurs in swampy woods.

[Ill.u.s.tration: _Pl. 62._ White Willow--summer.]