Seasonal Changes in Biomass Allocation in Eight Winter Annuals of the Mojave Desert

(1) Seasonal changes in biomass allocation were determined for eight species of winter annuals in the Mojave Desert-Astragalus sabulonum, Baileya pleniradiata, Oenothera deltoides and Schismus arabicus from a relatively moist sandy soil; and Camissonia brevipes, Chaenactis carphoclinia, Phacelia crenulata and Plantago insularis from a dry rocky soil. (2) In all species, roots comprised 12-22%4 of total biomass until late in flowering, when root allocation declined. (3) Maximum investment in reproductive structures varied among species from 16 to 50% of total biomass. (4) The differences in allocation strategies were species-specific, not site-specific. (5) No rapid changes in biomass allocation during the life cycle were observed.