Argania spinosa (L.) Skeels flowering phenology

Argan (Argania spinosa (L.)Skeels) flowering was observed at Ait Melloul, Ait Baha andArgana, three sites in the south-west of Morocco during twoseasons, 1994–95 and 1995–96. Glomerule count wasmonitored on first-year and on last-year growth shootevery twenty days. Season was the primary source of variation ofglomerule count on argan first-year and last-yeargrowth shoots. The first season was very dry when flowering beganlate April, while the second was very humid and flowering startedearly December. In both cases flowering precocity was associated toprecipitation precocity, i.e. flowering would commence whenapproximately 100 mm rain was accumulated. High positivecorrelation between glomerule count and precipitation were observed.But, considering the two seasons, glomerule count always attained itspopulation maximum in spring even if differences were observedbetween sites. However, intensity and duration of the peak were alsodistinct depending on shoot type: on first-year growth shoot,glomerules were abundant but would last for a short period, whereason last–year growth shoot, they were less frequent but wouldlast for a longer period. Not all trees flowered during a season,although some trees flowered every season, showing the extremes ofthe large variability observed for glomerule count abundance andduration within argan populations.