The Thymus Information Page |
Advice for using keys to identify thymes Keys can be daunting but don't worry, familiarity with the technical terms used will speed things up, as will getting to know some of the species. So lets start at number 1. 1 Leaves in general revolute, although some can be flat 2 Leaves flat 8 We are faced with a choice between two types of leaf. One which is flat, and another whose margin is rolled downwards. This would seem an easy choice on the face of it however in practice you may find it difficult to decide on a small thyme leaf whether it's margin is rolled or not. Another problem is that it says in general revolute, although some can be flat. It is very important to check a number of leaves from different parts of the plant. Don't make hasty decisions. Check and double check. It will save time and frustration in the long run. If you still can't decide then take your best guess and follow the link to the next relevant choice. I can also recommend keeping a written note of the choices youre making so that if you get to a dead end where neither of the choices fit, you can go back and take another branch of the choice tree. OK so lets say you've decided that the leaves are flat. We then go to 8. where we have 8 Leaves hairy 10 T. maroccanus Leaves glabrous or ciliate at the base only 9 Well, if the leaves are hairy all over you're laughing because its probably 10 Thymus maroccanus. (The number 10 refers to the position of maroccanus on the species description page and nothing else). You now go to the detailed description of the species and make sure that everything checks out. Of course, we're dealing with a living organism here which may vary in it's appearance within what is currently thought to be one species. The species description is a man-made attempt to classify nature rather than a prescription from on high. Some species are variable in some of their characteristics, leaf hairiness being typically altered by climatic influences if not others. Be rigorous in your reading of the full description. It's all too easy to try to make your specimen a particular species especially when you've been struggling with the key for a long time already, your eyes are getting tired from squinting through a hand lens or binocular microscope, and your head is spinning. You may find yourself failing to give equal weight to each part of the description. Its leaves are the right size and they're hairy so it must be maroccanus. I'll just ignore the fact that my specimen doesn't fit in any of the other respects. In many identifications there's often a degree of uncertainty but you must get the best fit you can with the material you have. If it doesn't really fit go back and start again. You might have followed the wrong link to the next pair of choices. If the leaves are not hairy but hairless or just with longish hairs at the base of the leaf you proceed to. 9 Leaves without basal cilia 10 Leaves with basal cilia 11 And so on. Good luck. Don't struggle. Take a break. Be rigorous, and above all enjoy it. |