Flowering and fruiting studies on E. deglupta

Stands of naturally occurring E. deglupta in the North Bainings – Open Bay – Wide Bay region of New Britain (black areas) confirmed and/or updated during a reconnaissance by helicopter on 9 June 1968.

Flowering and fruiting studies on E. deglupta

A planned long-running flowering study was started on 24 June 1968. Several of the marked candidate trees were observed regularly using binoculars to record the development of flowers and fruits over time. Also the amount of seed harvested from each tree was recorded. The periodicity of significant fruiting

events was also noted (some trees at Keravat had at least a few flowers on them all year round). Climbers collected flowering panicles in varying stages of development for detailed study. This is a summary of the results from these studies: • 90 – 200 panicle clusters per tree on six-year-old trees • Pistil22 6 mm long by 4 mm wide • Style 2 mm long, lengthening to 2.5 – 3.0 mm at the time the stigma is receptive • Anthers oblong, dorsifixed (versatile), 0.25 mmwide x 1.0mm long, dehiscing by longitudinal slits • Pollen triplete (triangular) with trilete (tri-radiate) scars, tapering to pointed tips, sticky, adhering in clumps (found on parrots’ beaks and on insects, especially on the “Green Tree Ant”23, among the Flowers of E. deglupta: 1. Straw principal pollination vectors of E. deglupta) coloured inner calyptra being shed, 2. Stamens inflexed, about to unfurl, 3. • Inner calyptra green to light green for 5 – 6 weeks, Filaments spreading, 4. Flowers fully greenish white for weeks 7 – 8 then straw coloured, open, stamens pale yellow, all fertile, anthers dehiscing releasing viable indicating it will fall off in a few days to one week pollen, stigmas still not lengthened or receptive. (About actual size.) • Anthesis takes one day from calyptra fall. Filaments spread outwards radially after being reflexed (folded inwards) in the bud, anthers dehisce exposing pollen. Pollen is already mature, as determined by germination tests, but stigma still not receptive at this stage. Stamens after spreading are numerous, prominent, showy and attractive to insects and birds. Anthers begin to turn brown and shrivel 2 - 3 days after they dehisce. • Stigma receptivity starts 1 – 2 days after anther anthesis, that is 2 – 3 days after the inner calyptra detaches, and continues for 2 – 3 days • Secretion of nectar does not start first from the stigma, though it does become visibly shiny and sticky at the onset of receptivity. Receptivity coincides with the inner walls of the staminal ring beginning to “perspire”, producing minute droplets that eventually fill the cupshaped void up to the level of the rim. Inside and below the staminal ring and above the ovary

22 Term used for the collective female reproductive parts of the flower. In E. deglupta the centrally located pistil has a swollen base (the ovary), containing potential seeds (ovules), a stalk (style) arising from the top of the ovary and a pollen-receptive tip (stigma). 23 The usually red to orange coloured Oecophylla smaragdina is a species of tree-inhabiting ant found in tropical Asia and Australia. These ants form linked colonies with multiple nests in the canopy of one or more trees, each nest being made of live green leaves stitched together using the silk produced by the ant larvae. They were especially prevalent in the Kamarere plantations at Keravat and when disturbed capable of inflicting a painful bite with their fangs because they could inject concentrated formic acid through any broken skin.