The Sisyrinchium (Blue-eyed-Grasses) genus should not to be semantically confused with the similar sounding Genus
Not to be semantically confused with Black-Eyed-Susan (Rudbeckia hirta) a yellow flower belonging to the Dandelion & Daisy Family (Asteraceae).
Easily mis-identified as :
American Blue-eyed-Grass (Sisyrinchium montanum) but that has deeper blue flowers that are usually larger at 25-35mm across (rather than 15-20mm of Blue-eyed-Grass and the above photographs). Any colony of Blue-eyed-Grass also has some specimens with branched stems with a single flower atop each one [and a single branched specimen was found - so it qualifies as Blue-eyed-Grass in this respect] whereas American Blue-eyed-Grass is un-branched, and the flowers are upright when it is in fruit (rather than arched as here and in Blue-eyed-Grass). But Blue-eyed-Grass grows in wet meadows and stony ground by lakes whereas the photos above and
American Blue-eyed-Grass grow in grassland. So, the above specimens qualify as Blue-eyed-Grass in most respects apart from two: the habitat (Nob End is not near a lake, nor is it a wet meadow) and the colour of the flower which is not pale-blue (unless Clive Stace means pale-blue on the outside of the petals rather than on the inside - but he doesn't say that).
On account of the above photographs not having pale-blue flowers your Author originally decided that these were
American Blue-eyed-Grass until he discovered a single specimen with a branch which immediately disqualifies it. But that still leaves the blue/violet flowers of the above specimens not matching the specified requirement of pale-blue for Blue-eyed-Grass and it was not growing in a wettish area. It could be
American Blue-eyed-Grass but then all the other physical parameters will be in-correct. You pay your money and take your choice.
If it is any consolation, another wildflower website has the same population at Nob End down as
American Blue-eyed-Grass, but even they have reservations about its true identity. Maybe I should enter the same population twice, as both species. In the third week of July 2013 the Ranger for Nob End (and Moses Bank Country Park - but who has since retired) came upon your Author who informed me that the general opinion was that it was bermudiana, so it looks as though your Author backed the correct horse (purely by luck as it seems).
Prof. Clive Stace says that it is often mistaken for
American Blue-eyed-Grass (Sisyrinchium montanum), especially in Ireland. Your Author thinks he can understand why: neither flower description fits the actual flower! Perhaps the key is wrong? Or maybe the plant itself has got it wrong ~
It occurs to your Author that this plant is in a quantum superposition of the two states, being neither montanum nor bermudiana, but that ill-defined intermediate between the two both at once, a quantum entanglement of the two forms connected by a worm-hole. Only by observing the plant can the wave-function collapse into one or the other form. In this instance the quantum state has collapsed into bermudiana, but to another observer it collapsed into the montanum form.
Some similarities to : Yellow-Eyed-Grass (Sisyrinchium californicum) but that has bright yellow flowers and to Pale Yellow-Eyed-Grass (Sisyrinchium striatum) but that has paler yellow flowers.
Slight similarities to
Gentians in that it is blue/violet with six petals, but closer inspection soon reveals the many huge differences.
Uniquely identifiable characteristics
Distinguishing Feature : Un-mistakably a Blue-eyed-Grass, one out of a possible two. The strip-like stem is a real giveaway and on its up to 30cm length it is usually twisted by at least half a turn.
No relation to :
Blue-eyed Mary (Omphalodes verna) [a plant with similar name belonging to a different family].
It is NOT A GRASS.
Unusually the stem is very flattened, almost like one of those white paper tie-wraps used to close sandwich bags (those strips of paper with a wire going down the inside middle). You could say that the stem was round (it is, but of very small diameter) with two wings either side, which is how the stem is described in the properties section. The stems also usually have a twist.
The status of the plant is questionable - it may have been introduced from America, or it may be native. Many are escapees from gardens.