I have just started the Identiplant course with BSBI (Botanical Society of Britain and Ireland) administered by FSC (Field Studies Council). This is an on-line wild flower identification course that runs from February to August looking at a different plant family every 2 weeks. It has just started with an introduction to classification and names and one of the topics is the distinction between plants according to the number of seed leaves (cotyledons) they have. Those with one seed leaf being monocotyledons and those with two, dicotyledons.
Although I already knew about monocotyledons and dicotyledons I had not really thought that there might be other useful diagnostic features that might be associated with them. Monocotyledons for example often have their flower parts in multiples of 3 , so 3 or 6 petals, stamens and styles etc., and may have parallel veined linear leaves. Now this is not always the case (for example May Lily has its flower parts in 4’s), but it is useful in the majority of cases to aid identification in the field.
Crocus is a very familiar spring plant but, I am ashamed to say, not one I have properly looked at before. This one in a local churchyard has dark green linear leaves (about 3 mm wide) with a white central stripe. In cross section the leaf is not flat but with downward (revolute) curving edges. The plant appears hairless throughout but there are very small hairs on the filaments of the stamens and on the stigmas. The petals (tepals?) are joined together and are pure yellow on the inside but with purplish stripes (that extend from the upper part of the flower stalk) on the outside. The flower stalk has a translucent membranous bract around it. There are 6 tepals and 3 stamens and 3 styles. In other words it is a fairly typical monocotyledon.
According to Stace this plant is Crocus x stellaris which is a hybrid between C. angustifolius and C. flavus.