Key To Fall Yellow-Flowering Shrubs In The San Gabriel Mountains

This is a key to the most common shrubs that bloom in the fall with yellow flowers found along the roads of the San Gabriel Mountains. It is available in two forms:

• Key only

• Key with pictures

There are seven species of shrubs that produce copious yellow blooms along the roadsides of the San Gabriel Mountains in September and October of each year. Although to a beginner these species look fairly similar from a car traveling at 50 mph, it is very easy to distinguish these species up close. After becoming familiar with these species, it soon becomes easy to recognize the other species from the car as well. Only four of these species are common:

• Rubber rabbitbrush, C. nauseosus, is very common, lines the roads above about 4000 feet, and is almost always found in large masses when it occurs. It is easily recognized by its flowers, which consist of exactly five disk flowers and no ray flowers (ones with ligules or petals). There are a number of different subspecies which are easy to identify.

• Scalebroom, Lepidospartum squamatum, looks similar to rubber rabbitbrush, and also occurs in large numbers with a habit very similar to rabbitbrush. It is easily distinguished by its bright green glabrous stems and scale-like 2-3 mm leaves.

• Creek senecio, Senecio flaccidus var. douglasii, is a fairly open shrub, typically occurs in much smaller numbers, and has obvious ligules and a distinctive coloration.

• Parish's goldenbush, Ericameria parishii, is much less common than the above species. It typically occurs singly, and is a much more leafy plant with much wider leaves.

Not every shrub with yellow flowers blooming in the fall found in the San Gabriel Mountains is in this key; just the most common ones. Some Ericameria are missing; see Goldenbush Key for a few of the other less common species.

The key does not include Heterotheca species, since these are not in fact shrubs, but perennials with stems that seem woody, but die down to the ground each winter. H. grandiflora does not look very shrubby, and usually consists of just a single stem that looks like a telephone pole, hence its common name of telegraph weed. H. sessiliflora is a very low compact plant, much smaller than the shrubs in this key.

Go to:

• Keys to Identifying Selected Plant Groups in the SGM
• Plants of Southern California: Chrysothamnus nauseosus subspecies