It is similar in form to Senecio serra, both being four feet tall, have narrow and serrated leaves, and are topped with many small, yellow sunflowers.
but S. triangularis is more common than S. serra.
S. triangularis has single erect stems, reaching up to 10–120 cm (4–47 in) tall.
The stems have evenly distributed leaves.
The leaves are triangular, with tapered ends, hence the name.
The flowers have a prominent central dome, with ray florets around 8 cm wide.

As some plants are diploid, meaning having two sets of chromosomes, this can be used to identify hybrids and classification of groupings.
It has been counted as 2n = 40, 80.

It is native to temperate regions of America and is reportedly poisonous to animals.
It is similar in form to Senecio serra, both being four feet tall, have narrow and serrated leaves, and are topped with many small, yellow sunflowers. but S. triangularis is more common than S. serra. S. triangularis has single erect stems, reaching up to 10–120 cm (4–47 in) tall. The stems have evenly distributed leaves. The leaves are triangular, with tapered ends, hence the name. The flowers have a prominent central dome, with ray florets around 8 cm wide. 
As some plants are diploid, meaning having two sets of chromosomes, this can be used to identify hybrids and classification of groupings. It has been counted as 2n = 40, 80.
It is native to temperate regions of America and is reportedly poisonous to animals.
Senecio triangularis