——Sorry if you’ve seen this post before. I’m just trying to consolidate all my botany posts into one blog! I’ll have new content alternating with old content every week——
Sedges have edges
Rushes are round
Grasses are hollow, all the way to the ground
It’s botany time! Sedges (Cyperaceae), rushes (Juncaceae) and grasses (Poaceae) can be among the hardest plants to identify because they lack large, showy flowers. Frequently, people just lump all these monocots together and just ignore them. At least with the little rhyme above, you should be able to differentiate between these families. I’ll explain further below
Sedges have edges, refers to the fact that most sedges have triangular stems in cross section. In other words, if you tried to roll the stem in your hand, it wouldn’t roll nicely.
Rushes are round. This is pretty straight forward - rushes have stems that are round in cross section. Unlike the grasses, though, the centre of the rushes are filled with soft, typically white, pithy/spongy material. This pith is useful for a group of plants that lives mostly in wet habitats, and serves to maintain airspace for gas (CO2/O2) exchange.
Grasses are hollow all the way to the ground. While the rush stems are filled with pith, grasses are typically hollow. The only exception is at the solid nodes where leaves emerge.
So can you guess what we’re looking at here? It’s hard to tell from this photo, but you can barely make out the edges of this sedge. While most people fine sedges boring and ugly, they actually have beautiful stamens and styles. Because it’s wind pollinated, the reproductive parts dangle nicely in the wind and can often be bright and vibrant colours.