Sisyrinchium or the blue eyed grasses

S. campestre as seen in my native plant garden

Blue eyed grass – Sisyrinchium spp. – are some of my favorite flowers. It is probably really unfair to make that statement because I like a lot of native flowers, and “my favorites” change as the year progresses…

Anyways, I know two species (the common –or white – blue eyed grass, and the prairie blue eyed grass), and I was vaguely aware of the third – the mountain blue eyed grass. I thought I would check the Bible (in this context a reference to the Plant Bible and more specifically Swink and Wilhelms Plants of the Chicagoland Region) to see how to differentiate among them when not in flower and I was quickly taken down a botany rabbit hole. I will indulge you momentarily, but now back to the 3 species.

The blue eyed grasses are beautiful. Short (1 foot or less) and with slender leaves and a delicate flower that grows on top of the stem - they just really stand out. They also form clumps, which gives them an attractive “tufty” look. In addition, right before they bloom the flowers are protected by a lobster claw like bract. According to Doug Ladd’s Tallgrass Prairie Wildflowers, the 6 petals are actually 3 petals and 3 sepals that look alike (identical if you ask me).

Sisyrinchium albidum at Brookfield Prairie

The difference between white or common blue eyed grass and the remaining two blue blue eyed grasses (S. campestre and S. montanuum) is that the first one had 3-4 bracts (or 2-3 as described by Swink and Wilhelm), while the pair has those two bracts that cover the flower and remind me of lobster claws. The difference between the bluer of two species –  prairie blue eyed grass (S. campastre) and the mountain blue eyed grass (S. montanuum)  is that mountain blue eyed grass has larger capsules (>4.5 mm long) and the outermost bract is united for 2 mm or more. In the case of the prairie blue eyed grass the capsules are less than 4 mm.

Some easier distinctions: the prairie species is found in dry prairies (yes I know, genius) while the mountain one in prairies AND dune flats in calcareous soils, so in fact it is very rare. I almost want to say that if you are looking for S. montanum you probably know the difference between these two better that I can explain. Prairie blue eyed grass also blooms beginning of May while the mountain blue eyed grass end of May. The white blue eyed grass can bloom from May through June and is more commonly found. Also the more alkaline the soil, the whiter that species will get, which is an interesting fact.

So now that I went through this exhausting explanation I should mention that there actually are 5 Sisyrinchium species  in the region, two I was completely unaware of. And this is how I entered the rabbit hole, or more precisely fell into it…

When you open the key to the genus you are met in the options “Plants appearing to have cauline leaves “ or “plants appearing scapose” . It’s been a while since I looked up a plant so it began, but more about that later… in another post at another time.. stay tuned