52 NATURAL HISTORY OF 



considerable numbers. Our way lay for some miles over 

 low-lying, sandy, undulating plains, which presented so many 

 attractions for me in the botanical line, that my companions 

 soon distanced me, and I strolled along in solitude, filling the 

 large vasculum which was my constant companion in the 

 cooler parts of South America. Among the plants I met with 

 on this occasion were several yellow-flowered species of Com- 

 positce, the white Petunia observed at Monte Video, a yellow 

 (Enothera, a pale pink Convolvulus, a curious dwarf leafless 

 (probably Ehamnaceous) shrub, which had phylloid branches 

 profusely armed with formidable spines and bearing tricoccous 

 fruits ; some sand-binding grasses, and a dwarf Myrtaceous 

 plant, the white flowers of which presented a very attractive 

 appearance. These, together with a species of Dyckia, and 

 many other forms, all occurred in very arid soil ; while some 

 marshes which I passed yielded a variety of other plants, 

 among which I may instance a sundew (JDrosera), several 

 Leguminosae, a plant unknown to me with pinkish-white 

 flowers, fringed like those of our British bog-bean, but with 

 undivided leaves ; a small yellow-flowered Utricularia; a fern 

 {Lomaria Boryana) with a short thick stem (six inches to a 

 foot high, surmounted by a crown of very tough leathery 

 fronds ; and a composite plant resembling a Senecio, with a 

 flower-stem six to eight feet in height, on the branches of 

 which flocks of small finches were sitting. I noticed a 

 number of species of birds, including the burrowing owl 

 already referred to, which was very tame, flying about in my 

 vicinity, and perching on the bushes, making a curious thrum- 

 ming sound. Another remarkable sound which I heard, and 

 which for a time perplexed me from its subterranean charac- 

 ter, was produced by a burrowing rodent, the tucu-tuco 

 (Ctenomys Brasiliensis), which tunnels the sandy soil in all 



