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Telopea Vol. 6(4): 1996 
In the terminal flowers on a subunit, stamen enlargement appears unidirectional; 
the first stamen primordium is larger than the transverse stamen primordia that in 
turn are larger than the stamen primordium directly opposite the largest stamen 
primordium (Figs 36, 37). In the single flowers that lack an a-phyll, the first stamen 
primordium, in a transverse site, becomes larger than the other three stamen 
primordia (Figs 38-40). The second stamen primordium, approximately 180° from 
the first stamen primordium, is the next largest (Figs. 38, 40). After stamen initiation, 
the remaining floral meristem is flattish and bilaterally shaped in outline (Fig. 39). 
Carpel initiation begins as one portion of the remaining floral meristem begins to 
enlarge, usually the side closest to the largest stamen (Fig. 40). The higher part is the 
dorsal side of the carpel primordium (Figs 41,42). At a carpel height of approximately 
85 pm, the cleft becomes apparent on the ventral side (Figs 43, 44). The early 
development of the carpel is epeltate or conduplicate, with no apparent cross zone. 
Floral morphogenesis 
After initiation, the floral organs begin to differentiate. The tepal margins become 
appressed or valvate and two opposing tepal tips come into contact with one another 
over the other floral organs; the other two opposing tepal tips do not come into 
contact with one another but fit into the corners formed by the other tepals (Fig. 45 
— incomplete valvate aestivation). In bud, the tepal tips are slightly incurved and 
elongate cells differentiate at the tip (Fig. 46). Zonal growth beneath and between 
each tepal and its opposing stamen results in the epitepalous condition when the 
tepals are approximately 400 pm high (Fig. 46). Trichomes develop in the lower half 
or claw of each tepal (Fig. 47), each trichome the product of a single cell. The trichomes 
differentiate and become globose at the distal-most portion before anthesis (Figs. 48, 
49). A pair of bump-like processes develop on each tepal, a single process on each 
side of the tepal distal to the point of tepal-stamen adnation (arrow in Fig. 49). 
Additional bump-like processes dev^elop distal to the first pair of bumps. At anthesis, 
there can be three or four bumps per row (Fig. 50). 
The stamen primordia enlarge and differentiate at different rates. The median furrow 
becomes visible when the stamen primordia are 90 pm high (Figs 38,40). The transverse 
furrows form at a stamen height of approximately 125 pm (Figs 51, 52). The relative 
position of the transverse furrow is introrse compared to the differentiating connective 
(Fig. 52). A small connective appendage distal to the enlarging microsporangia becomes 
Figs 46-54. (right) Fig. 46 . Two dissected away tepals and stamens showing that zonal growth has 
begun between and beneath each tepal/stamen filament (0 complex. A small connt"ctive appendage 
is present on each stamen (cn). Fig. 47. Close up of dorsal surface of tepal and point of tepal/stamen 
adnation showing the initiation and enlargement of the trichomes. Fig. 48. Close up of dorsal surface 
of tepal and point of tepal/stamen adnation showing the enlargement of the trichomes over the 
adnate filament. Fig. 49 . Close up of dorsal surface of tepal and point of tepal/stamen adnation 
before anthesis, showing partially free filament and the mature globose ended trichomes. A bump¬ 
like process (arrow) has developed distal to the point of tepal/stamen adnation. Fig. 50 . Close up of 
dorsal surface of tepal and point of tepal/stamen adnation at anthesis showing three processes on 
each side of the tepal above the point of tepal/stamen adnation. Fig. 51 . Polar view of young flower, 
tepals removed, showing the development of the microsporangia via the presence of the transverse 
fumiws. Fig. 52 . Polar view of enlarging flower, one stamen removed showing the differentiation of 
the stamens and the small connective appendage (cn). Fig 53 . Oblique side view of flower with 
stamen and tepal removed showing the enlarging semi-tubular carpel primordium (G) with the cleft 
extending to the base and the differentiating stamens. Fig. 54 . Removed young stamen/tepal complex 
showing the distinct fused filament (fi) and the initiation of trichomes. Scale bars: 46, 49-50, 
53-54 = 100 pm; 47-48, 51-52 = 50 pm. 
