340 NOTES OF A BOTANIST 
few other perennial grasses, chiefly species of Panicum and 
Paspalum, besides the Grama dulce {Cynodo?t dacfylon), originally 
brought from Europe, but here so completely naturalised that, if 
allowed to spread, it would exclude almost every other plant. It 
is valuable as an article of fodder. A few annual grasses, chiefly 
species of Eragrostis, grow about the outer margin of the vega. 
Of sedges also (species of Cyperus and Scirpus) there are four 
or five species. 
Other herbaceous or suffruticose plants are a tall Polygonum, 
the handsome Typha Tf-uxillensis, the Yerba blanca {Teleianthera 
peruviana)^ several species of Chenopodium, including the strong- 
smelling Paico ( Ch. ambrosioides and multifiduni) \ a Cleome, a 
Portulaca, Scoparia dulcis, a Stemodium, and three or four other 
Scrophulariaceae ; a Melilotus, a Crotalaria, a pretty Indigofera, 
with numerous prostrate stems spreading every way from the 
root, and pink flowers, a Desmodium, a sensitive - leaved 
Desmanthus, a Sonchus, Ambrosia peruviana^ and a few other 
Compositae; a Datura, two species of Physalis, Dktyocalyx Miersii, 
Hook. f. (exceedingly variable in the size and shape of its leaves), 
and the ubiquitous Solaniim nigrum ; Verbena /iifora/is, two 
species of Lippia, Tiaridium i?zdiciim, a Heliophytum, three 
Euphorbias, a small Lythracea allied to Cuphea, and a few 
others. 
In the river itself occasionally grows a Naias, in dense 
masses, like those of Anacharis alsi?iastrum in English streams 
and ponds. . . . 
Two mosses, both species of Bryum, are occasionally found 
on the banks of the river Chira, and on the filtering-stones kept 
in houses, but only in a barren state. 
I did not remain long enough in the country to witness the 
full effect of the rains of 1864 on the desert. The first plant to 
spring up, in the ravines leading down from the tablazo to the 
valley, and then on the tablazo itself, were two delicate Euphorbise, 
distinct from those of the vega. A little later on they were fol- 
lowed by a fragile dichotomously branched Scrophulariacea (which 
is common on the coast to northward of Guayaquil) ; two viscid 
Nyctaginese (species of Oxybaphus) with pretty purple flowers ; and 
two or three grasses (one of them an Aristida), but very sparingly. 
The Yuca de caballo (Martynise sp.) also began to put forth its 
leaves, but the Yuca del monte had not, up to the 20th of April, 
shown itself above ground. I had seen far more wonderful 
effects of the rains of 1862 at Chanduy, where a desert nearly 
as bare as that of Piura became clad in a month's time with a 
beautiful carpet of grasses, of many different species, over which 
were scattered abundance of gay flowering plants. Something 
similar must have occurred this year to northward of the hills of 
Mancora, for people who travelled between Amotape and Tumbez 
