OTAY MESA VERNAL POOLS AND OTAY MOUNTAIN
APRIL 2005 PAGE ONE




This is another of the photo galleries prepared in 2018 for a Jepson workshop that took place back in 2005 before I ever started doing the galleries. This workshop concentrated on the flora of the Otay Mesa vernal pools and Otay Mountain areas of San Diego County. In normal rainfall years the vernal pools form on generally flat terrain of less than 10% slope in depressions above impervious soil layers typically of alluvial materials with clay or clay loam subsoils, fill up to a depth usually of no more than six inches, and last generally for two to four months normally November through March, then revert to dry conditions during the remainder of the year. Periods of inundation lasting six months or more which are very unusual would tend to produce marsh conditions, so the plants that inhabit vernal pool areas are not truly aquatic. Most of the historic vernal pool complexes that used to extend sporadically from Ventura County down into Mexico on the region's flat mesas have disappeared as a result of development, but there are still vernal pools preserved and recent work has been done in an attempt to conserve them. They are often home to colonies of fairy shrimp, tadpoles and insects in addition to a number of endangered plants. The community of Otay Mesa is located only a mile or so from the border and about ten miles inland from the coast, and Otay Mountain is 30-45 minutes further east within a range of ancient volcanoes called the San Ysidros, and its summit is at 3500'. The world's largest stand of Tecate cypress trees is contained within the Otay Mountain wilderness. The name Otay is derived from the Kumeyaay language and although its meaning is disputed, possible meanings include "brushy," "big mountain," or just "big." This workshop was led by botanist Scott McMillan. An asterisk next to the common name indicates a non-native species of which we saw very few.


   
Otay Mesa mint
Pogogyne nudiuscula
Lamiaceae


 
American wild carrot
Daucus pusillus
Apiaceae


 
 
 
Bristly matilija poppy
Romneya trichocalyx
Papaveraceae

[Named for Dr. Thomas Romney Robinson, 1792-1882]
 
 
 



 
Woolly blue curls
Trichostema lanatum
Lamiaceae



   
Yellow-stemmed bush mallow
Malacothamnus densiflorus
Malvaceae


   
Yellow pincushion
Chaenactis glabriuscula var. glabriuscula
Asteraceae



   
Canchalagua
Zeltnera venusta
Gentianaceae

[Named after Swiss botanists Louis and Nicole Zeltner]
 
Canyon sunflower
Venegasia carpesioides
Asteraceae

[Named after Padre Miguel Venegas, 1680-1764]
 
Big-bract verbena
Verbena bracteata
Verbenaceae
 


 
Ashy spike-moss
Selaginella cinerascens
Selaginellaceae


 
Chaparral broomrape
Orobanche bulbosa
Orobanchaceae
 
 
 
Wild oxalis
Oxalis pilosa
Oxalidaceae


 
Clover fern
Marsilea vestita ssp. vestita
Marsileaceae

[Named for Italian naturalist Luigi Ferdinando, Count de Marsigli, 1658-1730]


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