482 A NATURALIST IN THE PACIFIC chap. 



such as we find at Arica. In those coast localities, as at Arica, 

 Callao, and Chancay, where salt-water pools or brackish lagoons 

 lie behind the beach, or where a stream or a river empties into the 

 sea, Sesuvium portulacastrum, Heliotropium curassavicum, and a 

 Salicornia are to be generally noticed, and, as at Callao, Batis mari- 

 tima may also abound. On the Chancay coast, about 30 miles 

 north of Callao, there lies inside the shingle-beach a large shallow 

 lagoon of brackish water (spec. gr. i"oi2) with extensive muddy 

 marginal flats, the temperature of the water at the edge being at 

 mid-day on Feb. 3rd, 90° F. In the water flourished Ruppia 

 maritima, which was also exposed in dead, dry, matted masses on 

 the bordering mud-flats. On these mud-flats grew Sesuvium 

 portulacastrum, which near the water's edge was associated with a 

 small species of Salicornia, whilst further away from the water it 

 was accompanied by Heliotropium curassavicum. 



But the most typical beach-flora of the Peruvian coast is such 

 as we find on the dry beaches skirting the base of sand-covered or 

 barren hill-slopes such as occur at Mollendo, Ancon, and Paita. 

 As at Ancon, sand-covered hills and plains may extend miles 

 inland, displaying here and there lines of shifting sand-mounds or 

 " medanos." On such beaches we may often find only a solitary 

 plant, a species of Sesuvium which seems to differ only in its 

 larger flowers, its much larger leaves (2 inches long), and its stout 

 stems, of the thickness of the little finger, from the ordinary 

 Sesuvium portulacastrum. This seems to be the only plant that 

 can make its home on such beaches. At Mollendo, where there 

 are signs of desiccated pools behind the beach which are occasion- 

 ally filled with sea-water, the vegetation was of an intermediate 

 character and more abundant ; and here grew Sesuvium portula- 

 castrum, a tall Salicornia, and Suseda fruticosa ; whilst the 

 commonest plant was a prostrate Nolanaceous species with a 

 handsome purplish flower. 



Excepting with the fruits of Batis maritima, and perhaps the 

 buoyant joints of Salicornia, scarcely any of the prevailing shore- 

 plants of the coast of Peru possess a capacity for dispersal by 

 currents. In this zone I rarely found any seed-drift on the 

 beaches. Much rubbish, such as roots of bamboos, however, may 

 be brought down by the rivers ; and where the Humboldt Current 

 strikes a bend in the coast we get a repetition, on a smaller scale, 

 of the scenes on the Antofagasta beaches. Ancon Bay, for 

 instance, receives much of the floating offal of the south. 



