Saccharum giganteum

Poaceae, the grass family

Worked with John this morning on our glacially progressing “photo guide to the native trees and shrubs of South Florida” project.  In the wet pine woods along the drive home I beheld a beautiful sign of October in Florida.  No, not pumpkin spice, but plume grass with plumes.    There’s only a narrow window in time to enjoy that sight. 

Plume grass comes in different geographically separate forms, and different populations even have different chromosome numbers, all multiples of 30.   It has long been known that there is something “funny” about this species.   

In recent years DNA has revealed plume grass as an ancient hybrid combining two ancestors:  one ancestor is a close relative of sugarcane (Saccharum officinarum).  The other ancestor according to one molecular study  is a “silvergrass” in the genus Miscanthidium, not even found in the Americas, although the story is far from complete.

And here’s another head scratcher.   In North America plume grass appears largely to be cross-pollinated with normal flowers, but the species extends southward into Mexico and southward where “Saccharum giganteum” grades into a very similar relative, often called Saccharum trinii, in which the flowers self-pollinate and never open.