Although a native of the Mediterranean region, it adapts itself thoroughly to our climate, being perfectly hardy in all but the coldest parts of our country, and ripening its acorns plentifully in districts near the coast. Indeed, it is doubtful whether in its native region many loftier specimens can be found than one at Rossanagh, in County Wicklow, which, when I saw it in 1905, was 80 feet high. The tallest recorded by Mr. Elwes stands in the garden of the Hotel Hassler at Naples, measuring, in 1910, 90 feet high and 12½ feet in girth.
We commonly follow Roman usage in calling this tree "ilex," nor is it easy to understand why Linnæus appropriated this name for the holly, because Pliny plainly distinguishes between them, writing of the holly as "aquifolium." In English vernacular this oak was known as the holm oak, which is a corruption of hollen oak—i.e. the holly-like oak, because it is evergreen and the leaves of young plants are spined, though not so strongly as those of the holly.
Pliny has a great deal to say about this tree. He tells us that in the Vatican of Rome there was in his day an ilex older than the city, bearing a brazen plate inscribed with Etruscan characters, showing that it had been sacred of old. He also states that at Tivoli there were three holm oaks flourishing which were growing when Tivoli (Tibur) was founded centuries before Rome. Now, considering that Rome was founded about B.C. 750, and Pliny died about A.D. 115, it appears that the traditional age attributed to certain trees in his day was as liberal as it remains in ours. It would not be rash, however, to venerate the splendid ilexes in the grounds of the Villa Pamfili and the Villa Borghese at Rome as lineal descendants of the trees that Pliny loved.
In suitable districts near the sea the ilex is invaluable as shelter. Once established, it stands the roughest buffeting of storms without disfigurement. I am writing these notes within a hundred yards of an ilex at Ardgowan, on the Clyde. It is about 50 feet high, and stands isolated on a bare lawn, exposed to all the fury of tempests that come roaring up the firth, twisting its boughs in the most violent manner. Yet these are so tough as never to be broken, and the tree remains a model of symmetry and grace.
At Holkham, in Norfolk, there is a large grove of ilex, called the Obelisk Wood, the like of which for extent is not to be seen, I think, elsewhere. At Tregothnan, in Cornwall, also an immense number of ilexes have been planted in a long avenue beside the sea. It is remarkable—unique, probably—but it is not an arrangement to be recommended for displaying the peculiar beauty of the trees, which consists in their massive foliage. The branches meet overhead, and as you drive along under them the effect is gloomy.
Very near of kin to the ilex is the cork oak (Q. suber), which grows all through the Spanish Peninsula and the Mediterranean region, except in those parts where limestone or chalk forms the soil. Of all the oak family, this comparatively humble member is of most importance to civilised life, for no efficient substitute has been devised for cork in some of the uses to which it is put. The annual consumption must be enormous; it is wonderful how the supply is maintained. Having no qualities to recommend it to the landscape gardener, the cork oak is only fit for growth in this country as a curiosity, and there only in the eastern and southern English counties. In the midland and northern districts it may exist, but cannot rightly thrive.
Many hybrids have been reared from the ilex. One of the choicest is Turner's oak (Q. Turneri), said to have originated in the Holloway Down Nursery, Essex, in 1795, as a cross between the ilex and the common English oak. It is of moderate stature, not greatly exceeding 50 feet, and is semi-evergreen, retaining its leaves, which are of a bright, rather light green, till February. The Lucombe oak (Q. Lucombeana) is also sub-evergreen, a hybrid between the ilex and the Turkey oak (Q. cerris), but is a much loftier tree than Turner's oak; the foliage inclines in colour to the ilex, but the leaves approach those of the Turkey oak in form, the under surfaces being clothed with white down. This variety was raised about 1765 by William Lucombe, of Exeter.
Another remarkable hybrid, apparently between Q. ilex and Q. cerris, is the Fulham oak, of which the finest example I have seen in Scotland grows on the banks of the Ayr, in the grounds of Auchencruive.
Although these hybrid oaks ripen acorns, they cannot be relied on to produce exact counterparts of their parents, the offspring of cross-bred seeds always tending to revert to one or other type in the cross.
Of the forty-seven North American species of oak enumerated by Sargent, none is to be desired by reason of the quality of its timber, which in every instance is inferior to that of our native species; but three, at least, have proved their value in this country as highly decorative trees, owing to the rich tints of the foliage in autumn. These are the red oak (Q. rubra), the scarlet oak (Q. coccinea) and the pin oak (Q. palustris). These are all trees of great stature, the pin oak having already exceeded 100 feet in height in England, presenting a gorgeous display when its leaves turn scarlet in the fall. In Scotland, however, the summer is not always warm enough to produce these fine colours; in wet, cold seasons the foliage remains green till the early frost blights it into brown.