Aquatic Plants of Sa7i Diego. 12^ 



in comparison the tules and reeds and rank vegetation along the 

 borders of the largest lakes. 



Later in the season, Downingia pulchella and Pogogyne un- 

 diuscula, with several less conspicuous plants, took the place of 

 the minute vegetation, and carpeted the pools and ponds; still 

 later, golden bloomerias and blue brodiaeas, and other beautiful 

 liliaceae were found; these, in turn, gave way to a few compositae, 

 which finally surrendered the field without a murmur to the 

 lichens on the cobblestones, that were to reign in silence, and 

 alone, in this kingdom of nature during the dry season that 

 followed. 



Marsilia vestita, common to lagoons at high altitudes, Amman- 

 nia latifolia, Echinodoris rostratus, and other water plants made 

 an appearance during the season of 1884, on the borders of a 

 larger lagoon, near the level of the sea, which is usually a dry 

 flat. Numerous species of Potomageton were discovered in vari- 

 ous portions of the county in running streams, and various other 

 genera were found to be represented in the neighborhood of San 

 Diego, by plants new to our flora. 



On high mesa lands among the hills between the old missions 

 of Santo Tomas and San Vicente, in Lower California, I found in 

 1886, the same species of Pilularia, Elatine, Isoetes, Tillaea, and 

 Callitrichae that I had previously collected on the mesas, back of 

 San Diego city. A portion of these plants I had also observed in 

 similar miniature lagoons in the Tijuana, and in the Guadaloupe 

 valleys. The Pilularia was first described from South America, 

 and has been collected as far north as Santa Barbara. 



The fresh-water lagoons back of San Quentin bay, on the north- 

 west coast of Lower California, presented a variety of plants along 

 their borders. None of the previously mentioned species were 

 found, but rather, non-aquatic plants seemed to predominate. The 

 most interesting discovery was the new grass named by Dr. Vasey, 

 Orcuttia Californica, — as the type of a new genus. A Pogogyne 

 was found other than our San Diego species, but an umbelliferae 

 grew in abundance together with a common Mimulus that is fre- 

 quently found near water. 



It will be seen that the aquatic plants found in the vicinity of 

 San Diego, grow under very peculiar conditions. Instead of run- 

 ning streams and permanent ponds and lakes, in which to carry 

 on the warfare for the ' survival of the fittest,' they have to accom- 

 modate themselves to very minute bodies of water, that have only 

 a precarious and uncertain existence during the more favorable 

 seasons; they must be contented to appear only once or twice in 

 several years, and when tempted by the genial rain 'to make their 

 debut, must be prepared lor either an aquatic, sub-aquatic, sub- 

 merged, or a terrestrial life. 



Similar conditions, I believe, are found on the west coast of both 

 North and South America, but with the data at my command I 



