Some observations on leaf phenology MICHAEL BRAITHWAITE
Myrrhis odorata (Sweet Cicely), in the lane at Clarilaw. Nicola Nixon
M
ost of us are not trained ecologists, so, while we are used to reading studies of flowering times in plants, especially records of first-flowering in relation to climate change, it is seldom that we meet studies of how the leaves and stems develop over the season. I have long enjoyed the abridged version of Comparative Plant Ecology (Grime et al., 1988). This did much to develop my desire to learn more, so in 2020 I selected twelve common species to follow through the season in a short stretch of lane by my house at Clarilaw, Hawick (v.c. 80). I divided each month into four equal parts, of which there are 48 in the year. In each of these parts I observed for each species whether there were basal leaves and whether they were growing or resting, whether there was a stem and whether it was growing, and whether there were flowers. Due to health issues, the study was cut short in mid-August 2020, but, as the plants of all the chosen species were nearly ready to die back by then, not much was lost. I enjoyed the project and learnt much, though nothing ground-breaking. I now present detailed accounts of four of my twelve species, together with short notes on the other eight, in the hope of encouraging others to carry out similar studies. 6
BSBI NEWS 148 | September 2021
Ficaria verna (Lesser Celandine)
One of the species I chose was Ficaria verna, and I selected a dense colony under a hedge to follow. It proved to be full of surprises (Figure 1). Leaves started to appear in the second week of January and ground-cover was complete by the second week of February. Then nothing happened above ground for a long while, though I suspect that the root-tubers were swelling underground. Not until the third week of March did the first flowers appear. The early flowers were borne on leafless stems. At the same time leaf-bearing stems started to grow until it was almost as if there was a second layer of leaves jostling for light with the early leaves. The leaf-bearing stems usually grow a flower at the tip and may branch, by means of a branch-stem growing out of one of the leaf-axils. The branch will also flower. The flowering was sparse to begin with, but for three weeks from the beginning of April flowers were more plentiful. Then the flowering tailed off abruptly over a single week. Meanwhile the leaf-bearing stems were producing bulbils in the axils of the stem-leaves and, having done so, died off quickly over the first two weeks of May. The leaf-bearing stems grow at an angle and flop down to deposit their bulbils in a neat line radiating out from the base. The stems
