766 
Telopea Vol. 6(4): 1996 
and the carpel cleft in the third, terminal flower, with no subtending bract, is facing in 
a position directly opposite where one would have expected to find the y-phyll (* in 
Fig. 56), the dorsal side of the carpel next to the largest stamen that is next to the first 
initiated tepal. In virtually all cases examined, the carpel cleft was facing away from 
the subtending bract or the site where a bract would be predicted (42 other single- 
flowered, two-flowered and three-flowered subunits were investigated). 
Tlie top of the carpel appears tubular or porate at a carpel height of ~ 250 pm 
(Fig. 57). Enlargement of the base of the carpel represents the early morphogenesis 
of the ovary (Fig. 58). At a similar stage, the differentiation of the stigma occurs with 
the differentiation of papillae around the inner surface of the distal pore (Fig. 58). An 
invagination beneath the enlarging ovary represents the early development of a 
stipe (arrow in Fig. 58) at a carpel height of approximately 500 pm. The stipe continues 
to elongate (Fig. 59). The suture line is persistent (Figs 60-61). Papillae continue to 
differentiate on the porate stigmatic area (Fig. 61) and after anthesis when the stigma 
becomes receptive, the papillae are extended (Fig. 65). 
Two ovule primordia are initiated in lateral positions on the placental margins at 
about the same time as stipe elongation (Fig. 62). Tlie outer integument is initiated 
after the inner integument and the young ovules begin to curve downwards into the 
loculus (Fig. 63) attaining a hemitropous condition at anthesis (Fig. 64). 
Discussion 
Inflorescence and floral form 
The mature inflorescence structure is dramatically different from that in other 
members of Proteaceae that are basically racemiform or elaborations of a raceme. 
The inflorescence in taxa of Grevilleoideae appears more complex on account of the 
presence of two flowers or flower pairs in the axil of common bracts along principal 
axes. Nevertheless, the inflorescence structure in Grevilleoideae is racemiform, the 
flower pairs being the product of a developmental modification of first order axillary 
meristems or subunits (Douglas & Tucker 1996a). The inflorescence of Carmrvonia is 
paniculiform in outline, with a decrease in modular branching as one ascends the 
inflorescence, and has terminal flowers on most modular axes, without dichasial 
units or cymes. In Carmrvonia, the inflorescence is a panicle as defined by Rickett 
(1955): 'a loosely branched inflorescence of which the ultimate units may be of 
various types'. However, Briggs & Johnson (1979) called for a more strict definition, 
and restricted the term panicle to anthotelic inflorescences in accord with the usage 
of Troll and Weberling. In the material examined, there is no terminal flower on the 
main axis. In this case, the inflorescence of Carnarvonia is most similar to a 
pleiobotryum in accordance with Troll (1964). Mueller (1867) described the 
inflorescence as 'racemo-paniculate' although a paniculiform raceme would better 
define the basic condition of the inflorescence as an elaboration of a raceme. 
Developmentally, the diverse inflorescence architecture of Carnarvonia is somewhat 
plastic. There are several different developmental pathways of the axillary meristem 
from the point of origin and subsequent development. The simplest model to explain 
the elaboration of the inflorescence is the timing of commitment and differentiation 
events of the axillary meristems and their products within a subunit (Fig, 66). Within 
the axil of a bract from the main axis or a subunit, an axillary meristem enlarges 
(Fig. 66A). As the basic unit of construction, an axillary meristem will produce the 
first two organs in transverse positions in relation to the subtending leaf or the 
