California Naturalist Outing
Lower Arroyo Seco Park
Pasadena, CA
9 a.m. – 11:30a.m.
- From the Rose Bowl Parking Lot (south side) near the aquatic center.
- Route: Footpath along the road to the trail head
- Weather: Cold, 54°F, overcast and damp. No rain at visit time but signs of rain were everywhere.
Visit to the Upper Arroyo Seco
This trip was on a day class had been canceled.
The weather had been bad, but my own oversight failed to check the class email. Seeing no other class members, I opted to stay to naturalize in the adverse weather. On this trip my goal was to observe the oak forest and sage/chaparral meadows. The ravens were out and swooping about. Grass was growing taller and seeming more pronounced than previous trips. In the sage meadow, the soil seemed dry and compact in places, as though the rain never reached it. Hair or web like mats showed signs of moisture in-between buckwheat’s.


Near the restoration plots, black mustard can be seen, beginning to colonize and invade. The tall Ponderosa pines stood over the lush meadow. Everything green was dewy and damp. Nestled in the grass was a single yellow field cap mushroom.

Further on in the field, was a host of oddities: mounds of soil, an old concrete drinking fountain and an old tree limb covered in woodpecker holes and filled with acorns. In the sky, a raptor drove the other birds and to alarm as it flew and perched high in the trees.


As human pollutions go, I was surprised by the number of noises in the space. Air leaf blowers, lawn mowers, cars, horns mixed with winds and bird calls. It made for a cacophony in the still canyon.
Moving back up the trial, I spent some time in the oak filled space along the east canyon wall. Among the oaks I observed a hard brown fungus on a felled, but still living, oak, a hard mustard yellow polypore as it appeared to me.



Further up, in a slight dry slough, or vernal pool, along the east wall, I noted a pack-rat mound nestled among poison oaks and young sycamores.

Field Observations
- Tall Ponderosa pines
- Oaks
- Sycamores
- Buckwheat
- Grasses (various)
- Old debris
- Fallen limbs
- Birds (raven, hawks, sparrows)
- Ant colony
- Fungus
Observed Species
- Mustard yellow polypore – Fuscoporia gilva
- Yellow fieldcap – Bolbitius titubans
- Sugar bush – Rhus ovata
- California Buckwheat – Eriogonum fasciculatum
- Common Raven – Corvus corax
- California Harvester Ant – Pogonomyrmex californicus
- Grasses (various)

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