OwensPeak#1

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The Main Ant Pages On Wayne's Word: Images Taken With Nikon & Sony Cameras
  Ant Genera Index        Introduction        Ant Page 1        Ant Page 2        Ant Page 3        Nikon        Sony  
Facebook Trivia Note Numbers In Following Table Refer To Owens Peak North Of Palomar College
Many Additional Owens Peak Images Appear On Spiders & Insects and Other Wayne's Word Pages
Owens Peak #1: Geology, Lichens & Some Plants
© W.P. Armstrong (Updated 2 January 2016)
Before roughly ten million years ago, the landscape of southern California was as flat as eastern Kansas is today, a land of low rolling hills. There were no mountains, no frequent earthquakes, no San Andreas Fault, and fewer habitats for plant species, resulting in much less diversity. Furthermore, due to the absence of great mountain chains like the Sierra Nevada and Peninsular Ranges, southern California received summer rainfall. Then, about ten million years ago, an oceanic spreading center was subducted under the North American continental crust here (a collision of two tectonic plates). This began the process of mountain building in Southern California, including formation of the San Andreas Fault, migration of the Baja California peninsula away from mainland Mexico, the loss of our summer rainfall, and the diversification of species for which California is famous. Note: The hard, black rock at the summit of Owens Peak is much older. It was formed during the Jurassic Period, 145 million years ago, when dinosaurs roamed the Earth. Introduction by Tom Chester.
Armstrong, W.P. 2009 (with Tom Chester and Kay Madore).
The Santa Rosa Basalt Brodiaea: A New Species "Hidden In Plain Sight."
FREMONTIA 37 (2): 20-27.   
See PDF File
  Wayne's Geologic Time Scale in HTML  

View of Owens Peak looking north from the Palomar College Arboretum.

View from Owens Peak looking southwest toward Palomar College. In the foreground is an outcrop of Santiago Peak Volcanic rock. In the distance is the new Natural Science Building and the Palomar College Arboretum.

An outcrop of Santiago Peak Volcanic rock at the summit of Owens Peak, better known as Palomar "P" Mountain. This dark, fine-grained, very hard rock dates back to the Jurassic Period, 145 million years ago, to a time when dinosaurs walked the earth. This heavy rock is resistant to erosion and forms some of the higher topography in coastal San Diego County.

An outcrop of Santiago Peak Volcanic rock at the summit of Owens Peak.

Santiago Peak Volcanic rock from the summit of Owens Peak.

Magnified view of Santiago Peak Volcanic from Owens Peak showing rectangular plagioclase crystals.

  Santiago Peak Volcanic Rock In San Dieguito River  
San Marcos Gabbro In Nearby The San Marcos Mts.

Rock Formations On The Santa Rosa Plateau
Basalt Outcrops On The Santa Rosa Plateau

Jerusalem cricket (Stenopelmatus) on Owens Peak (Santiago Peak Metavolcanic).


15 Ant Species Found On Owens Peak
Click On Images To See Larger Images & Captions


1. Pheidole vistana

2. Pseudomyrmex apache

3. Prenolepis imparis

4. Messor andrei

5. Pogonomyrmex californicus

6. Solenopsis xyloni

7. Forelius pruinosus

8. Dorymyrmex bicolor

9. Linepithema humile

10. Tapinoma sessile

11. Crematogaster sp.

12. Formica moki

13. Camponotus dumetorum

14. Camponotus fragilis

15. Dorymyrmex insanus

16. Myrmecocystus cf. wheeleri


Lichens On Owens Peak

An outcrop of Santiago Peak Volcanic rock at the summit of Owens Peak, better known as Palomar "P" Mountain. This dark, fine-grained rock with white flecks dates back to the Jurassic Period, 145 million years ago. The lemon-yellow, crustose lichen is Acarospora socialis with a small patch of A. bullata (far right). The Acarospora doesn't have the marginally lobate thallus of Pleopsidium flavum and P. chlorophanum. The brown crostose lichen A. bullata is similar to the common species A. fuscata.

  List Of Lichen Images On Wayne's Word  

An outcrop of smooth, white-flecked Santiago Peak Volcanic rock at the summit of Owens Peak. The foliose lichen is Xanthoparmelia cumberlandia.

The weathered surface of this Santiago Peak Volcanic rock outcrop at the summit of Owens Peak is covered by colonies of crustose lichen. The circular gray colonies are Dimelaena radiata.

I originally identified this yellow crustose, areolate lichen as Acarospora schleicheri because it lacked the bright chartreuse coloration and marginal lobation of Pleopsidium flavum and P. chlorophanum. However, most modern lichen floras state that A. schleicheri is a soil (terricolous) species. In fact, even A. H. Magnusson (1929) describes A. schleicheri as a soil lichen in "The Yellow Species of Acarospora in North America" (Mycologia 21 (5): 249-260). In the latter reference under "growing on stone" this yellow lichen keys out to A. socialis. According to Kerry Knudson (personal communication, 2007), A. socialis is indeed the correct name for this species. The brown crustose lichen was identified by Charis Bratt as A. bullata. The white crustose lichen with marginal lobation is Dimelaena radiata.

Yellow coblestone lichen (Acarospora socialis) on Owens Peak. The areoles are about 1-1.5 mm in diameter, some of which contain a sunken hymenial layer. Photographed with Nikon D-40x with manual 55 mm micro-Nikkor macro lens and 3 extension rings at f-22 (one second exposure).

Tardigrades Belong To The Seldom-Seen Phylum Tardigrada

Magnified view of yellow coblestone lichen (Acarospora socialis) and tardigrade (black arrow) on Owens Peak. The areoles are about 1-1.5 mm in diameter, some of which contain a sunken hymenial layer. The tardigrade is only about 0.25 mm long (1/100 of an inch).

Minute tardigrades (Phylum Tardigrada) are only about 0.25 mm long (1/100 of an inch). Although they are fairly common on mosses and lichens, they are rarely seen. They are called "water bears" because of their fat body with stubby legs bearing claws at the tips.

  Selection In Tardigrades: Are They Over-Equipped  

Numerous gray colonies of Dimelaena radiata.

The bright orange crustose lichen (Caloplaca) occurs sparingly in Owens Peak.


Tasty Salad Plant On Owens Peak

Miner's lettuce (Claytonia perfoliata ssp. perfoliata) is abundant on shady, north-facing slopes in early spring.

A delicious miner's lettuce-avocado salad for dinner.

Be Very Careful When Reaching Into A Patch Of Miner's Lettuce!

Southern Pacific rattlesnake (Crotalus viridis ssp. helleri).

Another Southern Pacific rattlesnake in bushes along trail to Owens Peak,

Be careful when climbing around the boulders on Owens Peak north of Palomar College. When searching for ants, look carefully before placing your hands under shrubs or between boulders!

Beautiful red diamondbacks (Crotalus ruber) along trail to Owens Peak.


Interesting Spiders On Owens Peak

Orb weaver spider (genus Metepeira): The web consists of both an orb web and an irregular 3-dimensional web. The retreat is a tangled, knotted web made with debris and leaves woven into the silk, placed so as to make a small protective tent for the spider. When disturbed it quickly drops out of the leaf cluster retreat and returns when the danger has passed. The genus was identified by Jim Berrian of the San Diego Natural History Museum.

Silver argiope (Argiope argentata) on Owens Peak (28 October 2010).

  See Banded Argiope On Owens Peak  
See A Tarantula on Owens Peak


Some Plants On Owens Peak

Venus looking-glass (Triodanis biflora), a seldom-seen wildflower in bellflower family (Campanulaceae).

A few boneseed shrubs (Chrysanthemoides monilifera ssp. monilifera) are naturalized on shady, north-facing slopes.

  More Images of Boneseed (Chrysanthemoides monilifera ssp. monilifera)  

Petrorhagia dubia (Carophyllaceae), an uncommon naturalized weed on Owens Peak.

Mission manzanita (Xylococcus bicolor).

Wild sweet pea (Lathyrus vestitus var. alefeldii)

California poppies (Eschscholzia californica).)

Telegraph weed (Heterotheca grandiflora) is now considered to be a native plant.