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Telopea Vol. 6(4): 1996 
closer to the top of the main axis or one of the subunit axes, the meristem in the axil 
of the a-phyll tends to be larger and higher (Fig. 23) than in the a-phylls lower on an 
axis (Fig. 22), possibly indicating the transition to a floral meristem (see below). 
The y-phyll is initiated approximately 150 -165° from the p-phyll from the flank of 
the meristem on the subtending leaf side of the axis (Figs 21, 23, 25). Bract initiation 
continues from the inflorescence axis, the 5-phyll being initiated approximately 
135°-140° from the preceding primordium (Fig. 24). The anthotaxis approaches a 2:5 
spiral (Fig. 25) with the initiation of successive bract primordia. Axillary meristems 
develop in the axil of each bract. From each axillary meristem, the pattern of bract 
initiation can repeat the pattern described above (a & b in Fig, 26, E-K in Fig. 66). 
There are variations in the development of axillary meristems among the more distal 
metamers of an inflorescence axis that involve floral organogenesis and morphogenesis. 
The deviations are found primarily among the one- and two-flowered subunits. The 
results of these architecturally significant patterns are discussed in more detail below. 
Flower organogenesis 
There was variation in the position of flowers relative to the subtending bract on the 
principal axis as well as in the enlargement of the axillary meristem. In addition, 
there is variation in patterns of organogenesis in the axillary and terminal flowers. 
A floral meristem enlarges within a bract axil. If there are no other primordia (e.g. 
a-phyll) initiated, the floral meristem becomes tangentially oblate and more highly 
convex (Figs 27, 28) than an inflorescence meristem (Figs 16, 17) . There is variation 
in the shape of the meristem, some being more tangentially oblate (Fig. 29) than 
others (Fig. 27). The first tepal initiated is in a transverse position relative to the 
floral bract followed by the initiation of the second tepal in the opposite transverse 
position (Fig. 27). 
In other cases, when there are a- or P-phylls present, tepal initiation appears to 
follow the established phyllotactic spiral of the subunit. When there is an a-phyll 
only, the first tepal is initiated in the opposite transverse site relative to the a-phyll, 
positionally similar to where a P-phyll would be initiated (Fig. 30). In such cases, 
the second tepal is approximately opposite the first tepal. The third tepal is initiatiated 
in a site 90° from the second tepal (Fig. 30). Similarly, in subunits with an a- and 
p-phyll, the first tepal is initiated in the y-site, thus following the established 
phyllotactic pattern of the subunit. 
Sequential stamen initation is difficult to assess although the pattern appears similar 
to the patterns of tepal initiation. After initiation of the tepals, the floral meristem 
expands (Fig. 31). In flowers that develop from the remaining modular axis with an 
a-phyll and no P-phyll (the terminal flowers of a subunit), the first two stamens are 
initiated in sites opposite the first two initiated tepals (Fig. 32) and the third stamen 
is initiated 90° from the second and first stamen (Fig. 33). In other terminal flowers, 
the pattern of stamen initiation appears to be unidirectional from the subsequent 
site of the last bract primordium (unidirectional from the p-site in Figs. 36, 37). 
In cases where there is no a-phyll, the first two stamens initiated are in transverse 
sites opposite the tepals found in the approximate a- and P-sites (Figs. 34, 35). The 
sagittal stamens are initiated after the lateral stamens (Fig. 35). Each stamen is directly 
opposite a tepal (tepals removed in Fig. 36). In many cases, the sequential initiation 
of stamens is not determinable due to differential enlargement of the floral meristem. 
The stamen primordia appear to enlarge at different rates, presumably in a similar 
pattern to the specific inititiation sequence of the differently positioned flowers. 
