|Figure 59.Broad-leafed gum plant (Grindelia squarrosa)|
Habitat and range.The gum plant (Grindelia robusta) grows in California, while the broad-leafed gum plant (G. squarrosa) is more widely distributed, being of common occurrence on the plains and prairies from Saskatchewan to Minnesota and south to Texas and Mexico.
Description.The name " gum plant " is applied especially to Grindelia robusta on account of the fact that the entire plant is covered with a resinous substance, giving it a gummy, varnished appearance. It is an erect herb with a round, smooth stem about 1 1/2 feet in height. The leaves, about 1 inch in length, are green, leathery, rather rigid, and covered with resin. The plant branches freely near the top, each branch terminating in a yellow flower about three-fourths of an inch in diameter.
The broad-leafed gum plant, Grindelia squarrosa, is similar to G. robusta, except that it is smaller and less gummy in appearance. The leaves are much smaller and thinner and less rigid.
Part used.The leaves and flowering tops of both species, collected when the plants are in full bloom.