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Telopea 8(4): 2000 
constant within species, was highly variable within the genera and sections, with no 
clear patterns apparent. 
The colour of the cotyledons at senescence (6) differed from the pattern seen for roots 
of the same species, and was divided into two states: yellow to light brown versus red- 
purple to dark rust-red, the latter was the most common condition in Gymnostomn and 
Casuarina, and yellow or light brown in Allocasuarina. Cotyledon pubescence (7) was 
uncommon, but was observed in three Allocasuarina species in different sections. 
In A. acutivalvis, A. campestris, A. decaisneana and A. tessellata, the interpetiolar 
branchlets (9) always developed before those of the cotyledons, and these were then 
followed by lateral branchlets on the main shoot. In contrast, only interpetiolar 
branchlets were seen in C. cunninghamiana, C. cristata, C. obesa and C. glaitca and then 
only developing later than and posterior to the lateral branchlets. In 12 species, apical 
dominance of the primary shoot was suppressed, with replacement bv axillarv 
branchlets (15). y y 
Epicotyl-base colour (10) varied from green or yellow through to red or purple. As 
with cotyledon senescence, red or purple was most common in Casuarina. A. torulosa 
was the only Allocasuarina with a red-purple epicotyl and cotyledons. 
Primary shoot shape (11) varied from erect (Gym nostoma, Casuarina and some 
Allocasuarina spp.), slightly curved (various Allocasuarina spp.), to strongly curved (the 
predominant condition in sections Echinopitys, Ceropitys) or even curled (A. scleroclada 
and A. striata). The lateral branches were also strongly curved in three species of 
Allocasuarina including some, but not all, species where the primary shoot curled or 
was strongly curved. The primary branches (12) were generally compound, but simple 
Tranches occur in a number of species, although there were no clear supra-specific 
patterns. Nevertheless, simple cotyledon branches were only found in Allocasuarina 
sects Dolichopitys, Oxypitys, Platypitys, Echinopitys and Ceropitys. The node number on 
the mam shoot at which branching first occurred (13) was also largely constant within 
but variable between, species ranging from the second node in A. paradoxa to the 
twelfth node in A lehmanmam (both sect. Cylindropitys). There was an axillary branch 
sterile zone (14) present in C. cristata and A. thuyoides. In sections Oxypitys, Platmitys 
Echinopitys almost all of sect. Ceropitys, and A. monilifera and A. microstachya, a) the 
primary shoot aborts (15), and the main adult stem or stems develop from axillarv 
shoots arising from the cotyledon axils, and b) the lateral branch stem tooth apices 
were divergent. r 
Node 15 on the primary stem (17) in Gymnostoma was 4-toothed, with the remainder 
u u, TT 6S 6X , a ? lined bein 8 4 ‘ and 6-toothed (rarely 5-toothed). On lateral 
branchlets the tooth bases (18) were imbricate in Allocasuarina sect. Oxypitys Seedlings 
shoots°ofthp C r° pih J S : U P toabout three months old, superficially resemble 
shoots of the fern ally Lycopodium, where there are protrusions along the stems which 
give the impression of micophylls — a feature also noted by Torrey (1983). 
Discussion 
Seedling structure within the family is distinctive and highly derived, reflecting the 
unusual adult morphology. Accordingly, meaningful comparisons with the seedlings 
different fl a ^ eS & r ^ data revealed * number of patterns inlhe 
single cha f rarlL reS 'f G r M °i m ' 7 Se ? dM % s ' 111 P^ular, are readily identified by the 
s ngle character of strongly peholate cotyledons. Casuarina seedlings are not clearlv 
istinguished from those of Allocasuarina, although they tend hAave constricted 
cotyledon bases, and the senescent cotyledons and epicotyl are generS^rTto 
