Observations on the time of flowering of mayweeds.
Seedlings of Matricaria matricarioides, M. recutita and Tripleurospermum maritimum ssp. inodorum which emerged in the field from January to June took progressively shorter times to first anthesis, reaching minima of 40-50 days. After midsummer, the mean time from emergence to flowering lengthened, variation between individual plants increased, and seedlings which emerged after early (T. inodorum) or mid-August overwintered as rosettes, flowering in early summer (T. inodorum) or late spring. When grown in the glasshouse with photoperiods of 8, 13, 15 or 17 h, flowering was delayed as the photoperiod decreased. See also WA 22, 2917. From summary.