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With so many plants flowering prolifically this spring we have been really spoilt for choice.

In October we revisited plant family Proteaceae, taking a close look at the Horny Cone-bush, Isopogon ceratophyllus, as well as Victorian Smoke-bush, Conospermum mitchellii. Although in the same plant family we noticed these species differ in the arrangement of their female floral parts. The Horny Cone-bush has a pollen presenter whereas Victorian Smoke-bush does not.

The role of the pollen presenter can be described quite simply: the female floral part collects the pollen from the male whilst the flower is in bud and, on flower opening, presents it to the insect pollinators. On completion of this task the pollen presenter is then receptive to pollen from another plant, enabling cross pollination to occur. In other words the female is responsible for both jobs. What’s new!

Our investigation of Broom Spurge, Amperea xiphoclada var. xiphoclada, a member of plant family Euphorbiaceae, revealed that this plant species has single-sexed plants with an abundance of male plants and fewer females (observation only).

Male Broom Spurge flower
Male Broom Spurge flower

Female Broom Spurge flower
Female Broom Spurge flower

The term used to describe single sexed plants is dioecious.

A hand lens will confirm the presence of showy male yellow stamens, whereas the female flowers are not as obvious. They appear to be round in shape and dark in colour.

November was the month to take a look at Scented Paperbark, Melaleuca squarrosa, and Woolly Teatree, Leptospermum lanigerum, both members of plant family Myrtaceae.

Scented Paperbark
Scented Paperbark stamens

The bundled nature of the stamens is an identifying feature, distinguishing Melaleuca species from other similar members of Myrtaceae, for example Callistemon species.

Any Teatree flower is worth magnifying but we found the hairy nature of the flowers of the Woolly Teatree particularly beautiful.

Woolly Teatree
Woolly Teatree with style and stigma

Much discussion arose from the fact that the ovary of many of these flowers did not have a style and stigma. This was also observed on some flowers of Manuka, L. scoparium. Obviously some homework is needed, because these species are described as botanically perfect, containing both male and female parts.

Controversy is never far away in our monthly plant study group; your input would be most welcome.

Gail Slykhuis