|Correlation between leaf shape and habitat type across 578 grass species (Gallaher et al, 2019)|
One thing I have noticed is that the denizens of these habitats tend to have wider leaves compared to species that live out in the open, and I just read a paper that used this fascinating fact to try to resolve the evolutionary origins of the family Poaceae.
|The wide leaves of Oplismenus undulatfolius, which inhabit the shady undergrowth|
The evolutionary origins of grasses are still under intense study, but differing hypothesis place their original habitat either in forest interiors, in the open, or in forest margins. A new study sought to delineate these options by looking at the various leaf shapes in grass species (Gallaher et al, 2019). Forest grasses it turns out, do tend to have wider leaves than those species in the open, but unfortunately such changes in leaf shape might also be affected by other factors, such as climate and the photosynthetic pathway used by each species (whether C3 or C4).
|The broad leaves of a Dichanthelium, another denizen of more shaded areas|
|Ammophila breviligulata with narrow leaves. Habitat is open beach areas.|
|The narrow leaves of Panicum virgatum, another typical denizen of open areas|