Organogenic sequence of SCBs and PCBs during
differentiation in radiata pine. a, Longitudinal section of
an SCB with initiated bracts (arrowheads) (5 mg), ×28.5. b,
Longitudinal section of a 50-mg SCB showing fused bract-ovuliferous
scale primordia complex. An arrowhead indicates the ovuliferous scale
primordia, ×180. c and d, Longitudinal section of a 100-mg SCB with
developing bracts and ovuliferous scales (arrowheads), ×170 and ×5,
respectively. e, Female LSTB with developing SCB (100–300 mg) and DSB,
×1.5. f, Five-milligram PCB with developing microsporophylls (Mi),
×15. g, Longitudinal section of a developing 100-mg PCB after the
completion of microsporophyll (Mi) initiation, ×10. h, Male LSTB with
developing PCB (300 mg), ×1.7. BP, Bract primordia; SC, sterile
cataphylls.