These open rolling plains, called by the natives _campos quebrantados_, are generally studded thickly with stunted palms called yatais,[149] but not so thickly as to spoil the grass which covers them in spring and early summer, and even in winter they remain good feeding ground. Thick clumps of hard-wood trees[150] break up the prairie here and there into peninsulas and islands, and in the hollows and rocky valleys bushy palmetto rises above a horse’s knees. In general the soil is of a rich bright red, which, gleaming through the trees, gives a peculiarly warm colour to the land. All the French Jesuit writers refer to it as ‘la terre rouge des missions’. The Jesuits used it and another earth of a yellow shade for painting their churches and their houses in the mission territory. Its composition is rather sandy, though after rain it makes thick mud, and renders travelling most laborious. The flowers and shrubs of the territory are quite as interesting and still more varied than are the trees. Many of the Jesuits were botanists, and the works of Fathers Montenegro,[151] Sigismund Asperger and Lozano are most curious, and give descriptions and lists of many of the plants unclassified even to-day. The celebrated Bonpland, so long detained by Dr. Francia in Paraguay, unfortunately never published anything; but modern writers[152] have done much, though still the flora of the whole country is but most imperfectly known, and much remains to do before it is all classified. The _Croton succirubrus_ (from which a resin known as ‘sangre-de-drago’ is extracted), the sumaha (bombax—the fruit of which yields a fine vegetable silk), the erythroxylon or coca of Paraguay, the incienso or incense-tree of the Jesuits, are some of the most remarkable of the myriad shrubs. But if the shrubs are myriad, the flowers are past the power of man to count. Lianas, with their yellow and red and purple clusters of blossoms, like enormous bunches of grapes, hang from the forest-trees. In the open glades upon the ñandubays,[153] the algarrobos, and the espinillos, hang various Orchidaceæ,[154] called by the natives ‘flores del aire’, covering the trees with their aerial roots, their hanging blossoms, and their foliage of tender green. The Labiatæ, Compositæ, Daturæ, Umbelliferæ, Convolvulaceæ, and many other species, cover the ground in spring or run up trees and bushes after the fashion of our honeysuckle and the traveller’s joy.