Orlovich, Drinnan & Ladiges, Floral development in the Metrosideros group 
701 
Fig. 9. (left) Roral development in Wekhiodendwn longivalve. a, young flower bud showing the first 
sepal primordia (K). (BR - floral bract) (x 285); b, flower bud after the initiation of two sepals which 
are initiated in a decussate position relative to the bract and main branch. (BR - floral bract) (x 180); 
c, the first two petal primordia (P) initiated on the inner wall of the invaginated floral apex; note 
the similarity in size suggests a short intervening plastochron. The first evidence of the gynoecial 
depression is apparent (x 240); d, floral stage slightly later than c. The first petal primordium 
(P, right) is already quite large by the time the fourth petal primordium (P, left) is initiated. At this 
stage, there is no PSB opposite either petal (x 220); e, part of a flower bud showing one petal 
primordium (P) and stamen primordia (S). The stamen primordia are developing on the notched 
upper edge of a PSB. Note the formation of colleters (C) at the base of the petals but outside the 
zone of stamen initiation (x 140); f, one group of stamen primordia developing opposite a petal 
(which has been removed). The first stamens formed along the top and in the centre of each group 
(x 170); g, part of a mature flower bud showing one stamen bundle. There is a median separation 
of the filaments into two groups (x 50); h, flower bud just prior to anthesis with the sepals and 
petals removed. Each stamen fascicle is clearly cleft. C - colleter (x 28). (from DAO 239). 
Fig. 10. Mature half flower of Tristaniopsis laurina (x 13.2). (from AND 562). 
