Pittosporum revolutum

Posted on Updated on

Pittosporum revolutumFamily: Pittosporaceae
Genus: Pittosporum
Common names: Rough- fruited Pittosporum, Hairy Pittosporum
ALA reference

In my May notes I hypothesized that the plants of this species that have apparently perfect flowers (bisexual with pistols and stamens) do not set any fruit. The fruit is only borne on plants that have flowers that lack stamens and pollen. To test my theory I marked all the plants that had apparently perfect flowers with blue ribbons and all the plants with flowers that lacked stamens with pink ribbons. The results are now in and I can confirm that most of the plants with the pink ribbons are setting fruit but none of the plants with the blue ribbons have set any fruit. I am now fairly confident that this species is actually dioecious but can find no reference to this in any literature. It is interesting that the flowers on the male plants still have the female parts (although not functioning) suggesting that the species is still evolving. One final observation is that the male plants seem to carry more flowers on each flowering head than the female plants. (September 2010)

This shrub grows to about 3 metres and plants can be found scattered through the reserve. I’ve recently noticed that seedlings are starting to appear in the areas that have been cleared of weeds. The plant pictured flowered in September last year. The small fragrant yellow flowers are followed by quite large very rough fruit which turn yellow when ripe and then split to reveal a mass of sticky red seeds.

I am still in the process of testing my hypothesis that the plants of this species that have apparently perfect flowers (with pistols and stamens) do not set any fruit. The fruit is only borne on plants that have flowers which lack stamen and pollen. (May 2010)

Pittosporum revolutumThis shrub grows to about 3 metres and plants can be found scattered through the reserve. Most seem to have struggled with the drought but it is quite hardy as the plant growing on the very edge of the road at the dog’s leg in Cliveden Avenue can attest. The small fragrant yellow flowers are followed by quite large very rough fruit which turn yellow when ripe and then split to reveal a mass of sticky red seeds. While I was preparing the photo for these notes I suddenly realised that there was something wrong with the flowers. The flowers don’t have any pollen; in fact they don’t have any male parts at all. When I searched the bushland I found five plants with flowers and a number that haven’t flowered this year. All the flowers on three of the plants lacked male parts while all the flowers on two of the plants appeared perfect with both male and female parts as in the photo (note the resident crab spider waiting to catch a visiting insect).

Further study is required to discover if (a) individual plants produce the same type of flowers each year and (b) whether there is any difference in the quantity and quality of fruit produced by the two types of plants. What I do know is that the plant on the very edge of Cliveden Avenue, that has flowers with only female parts, did produce a quantity of fruit last year which were full of viable seed. I planted the seed for propagation and had a very successful germination rate although a lot did subsequently damp off. (September 2007)

Advertisements