Photo by Brigitte Robertson
For this February field trip, we went through the maze of short trails in the riparian areas behind Boulder Creek Elementary School. We had a friendly group of 11 people who had to learn plants the hard way as few plants were in bloom. We started with the easy ones: valley oak, interior live oak, oracle oak, redbud, and gray pine. From there, we found a white leaf manzanita (Arctostaphylos viscida) and common manzanita (A. manzanita) that were in bloom. They are in the heath family, Ericaceae, and since they were already pollinated and fertilized, it was easy to identify the ovary, style, and stigma if you pulled off the united flower petal.
This area has two willows, the arroyo willow and the red willow. We found a female arroyo willow in bloom and using a magnifying glass everyone was able to see the female ovary and the stigma – the only flower parts of a female willow. They grow on a catkin and are easy to identify as they are usually the first willows to bloom and the flower matures before or with the emerging leaves. They also have a fat-arched bud. The catkins do have nectaries on them to attract insects for pollination. Some willows are both insect and wind-pollinated, but the arroyo are only insect-pollinated.
Photo by Brigitte Robertson
For the other plants we identified, most were familiar with: mugwort, gumweed, buck brush, chaparral honeysuckle, pipevine, California poppies (not in bloom), California rose (Rosa California), coffeeberry, Fremont cottonwood, and leafless Oregon ash. All were not in bloom except for the pipevine.
This was an easy-level walk meant to teach participants a bit of a deeper understanding of plants rather than just identifying a bunch of plants. A brief explanation of photosynthesis and water movement was given to round out the participants’ knowledge. This was discussed in sections on the walk to learn the principles in specific steps. For instance, we discussed the 1000’s of pores (stomata, pl.) on leaves (for most plants on the lower part of the leaves) and how this lets carbon dioxide in and water vapor and oxygen out, a necessary part of photosynthesis and water transport in plants.