In all five species examined, seeds sown in autumn (April) produced th
e tallest plants. Later sowing resulted in early rapid stem elongation
and the initiation of flowers/inflorescences in developmentally young
er plants (fewer leaves on the main stem) and anthesis at a younger ag
e. Plants from the early sowing produced more open inflorescences at p
eak flowering than those of later sowing dates. It is therefore conclu
ded that early autumn rain results in the establishment of taller plan
ts which take a longer time to reach anthesis and peak flowering, but
at their peak these plants will produce more inflorescences and conseq
uently a more spectacular show than plants that establish later in the
season. (C)1996 Academic Press Limited