Seasonal patterns are described for growth and partitioning of dry matter and selected nutrients between
different age classes and types of plant organs of ramets of non-reproductive, presumed female clones
of Alexgeorgea nitens in native sandplain habitat at Eneabba, south-western Western Australia. New
rhizome extension and associated production of new culms and nodal roots are initiated following onset
of rain in autumn. Rate of growth of these parts remains slow through winter, peaks in spring and early
summer and then becomes much reduced in the hot, dry summer. The bulk (87%) of the season's dry
matter increment of new ramet parts is estimated to be derived from current photosynthesis, the remaining
13% by mobilisation of dry matter from older parts of the ramet, especially from 1- and 2-yearold
culms. Growth of new organs is severely reduced by removal or shading of culms at the beginning
of the season. Older culms and rhizomes carry substantial starch reserves, but mobilisation of this
reserve accounts for 2% at most of the dry matter gain of new organs of intact ramets, 19% of that
of shaded and 65% of detopped ramets. A substantial fraction of the starch pool of a rhizome segment
normally remains until its senescence, possibly as a long-term energy reserve, utilisable after destruction
of above-ground parts by fire or grazing. Concentrations of N, P, K, Ca and Mg in organ dry matter
of A. nitens are generally very low in comparison with species other than those Cyperaceae or
Restionaceae from similar habitats. There is no evidence of preferential storage in below-ground parts,
and efficiencies of emptying of nutrient reserves from senescing ramet parts are not high. Mobilisation
from older source organs of ramets of intact, unstressed clones is estimated to provide 14% of the new
organ's seasonal gain of P, 16% of Mg, 21% of Ca, 22% of N and 58% of K. Annual factorial increases
of a ramet in the studied nutrient elements range from 1.3 (for K) to 2.4 (for P), indicating flexibility
in exploiting sources of different nutrients as their respective availabilities change from season to season.
Limits in complexity: the contextual boundaries of Peter Carstairs’ "September"
