dock often seen on the steeper hillsides, and occasionally a shrubby Convolvulus. The Echiums reach great development on the islands. There are several peculiar species. The immense spikes of white or blue flowers are a common and striking feature of the landscape. Shrubby Hypericums also abound, both on hillsides and in barrancos.
The so-called "barrancos" are a rich field for the collector. They are deep, narrow cracks between hills which have been sundered by volcanic disturbance. Erosion has had little or no part in their formation. Many of them are not watered at all, and if followed to their sources are found to end blindly among the hills. In some the winter rains collect and remain as stagnant pools or slow-flowing streams through a part or the whole of the year. Others are beds of perennial brooks fed by springs among the hills, and sometimes, in seasons of heavy rains, the waters rise above their narrow channels and rush in floods to the sea, causing great devastation among the fields and homes of the farmers. Teneriffe, Canary, Palma, and Gomera are supplied with such streams and springs. The whole island of Lanzarote has only two insignificant and inaccessible springs; Fuerteventura is slightly better off, while Hierro is entirely dependent upon rain water, which is carefully stored in cisterns.
Valleys, of which there are notable ones—such as that of Oratava, called by Humboldt the finest in the world—are distinguished from barrancos by greater breadth and less precipitous sides, and are not necessarily volcanic in their origin.
The exploration of a barranco is a fruitful occupation. Rare orchids and many ferns spring from between the damp rocks. A shrubby crucifer is occasionally seen on precipitous ledges, and more commonly an equally curious spiny and woolly-leaved composite. The blackberry, which is common in all sorts of localities, here takes on peculiar forms, and leafless suckers thirty feet long swing down the bare cliffs, seeking rooting place.
The bottoms of the watered barrancos and valleys are scenes of tropical luxuriance. The carpet of vivid grass is studded with loose-strife, oxalis, and clover. Wild forget-me-nots love the turf closest to the springs, and our garden nasturtium flings bright-flowered trailers profusely over the banks of the brooks. Maidenhair fronds grow in delicate beauty under the dripping ledges of the rocks. The tiny-flowered speedwell carpets retired nooks, and a species of Lathyrus with large, royal purple blossoms tangles itself around the canes. Here and there are clumps of palm and of native willow, rarely a specimen of the once common Dracæna draco, the famous dragon tree which yields the red gum once so esteemed as a dye and used by the aborigines in embalming their mummies. This tree is by some thought to symbolize the dragon which guarded the golden apples
