Two Conospermum species, plus a botany lesson

Conospermum or Smokebush belong to the spectacular Proteaceae family.

There are more than sixty smokebush species occurring in most Australian States, but are most numerous and diverse in the SW region of WA (the wheatbelt). Generally they are low to medium sized shrubs, often with striking floral displays that are used in the cut flower industry. There are several species in the Esperance region, but two outshine the others when it comes to display. These are Conospermum distichum and Conospermum teretifolium.

The Conospermum distichum smokebush is a bushy shrub growing to less than a metre and usually (in the Esperance region) occurring in small colonies on deep sandy soil. It mass flowers during spring producing a striking bluish grey (smoky) floral display.

Smokebush, Conospermum distichum

Conospermum teretifolium the Spider Smokebush grows to over a metre, also on deep sandy soils, but as scattered plants or only a few individuals. The flowers form in dense creamy white heads during late spring to early summer.

Spider Smokebush, Conospermum teretifolium

Like most people interested in botany, I have often been caught out on identification. On occasion I have seen (to me) a new species and on keying out the botanical features, it eventually indicates that it belongs to this or that family. But being familiar with some species and genera within that family, I think it can't be as it looks nothing like them. So believing I have made an error, I retrace my steps, only to arrive back again at the highly suspicious family. So reluctantly I investigate, only to find the key was correct and I had encountered yet another variation of the taxonomic features.

These two Conospermum species are also very dissimilar, but now have a look at the flowers, first the C. distichum smokebush. Note the small petals and densely woolly flowers.

Now the Conospermum teretifolium the Spider Smokebush, see how large the flowers are in comparison, with no hairs and the long thin petals.

So how come these completely different plants have been placed in the same genus? The secret is in the structure of the flowers, and this applies not only to these two species, but also to the hundreds of other species in the large Proteaceae family. These Proteaceae plants are found in several countries, although Australia and South Africa have the greatest diversity of species. These include the Australian Banksia, Hakea, Grevillea, Isopogon, Persoonia, Conospermum, etc, also the Protea, Leucospermum, Leucadendron, etc, from South Africa.
The similarity of these plants world wide, is they all have four perianth-segments (4 petal-like structures), with four stamens that are either attached directly to the petal-like structures, or to the perianth (flower) tube itself. There are other features like a superior ovary (where the floral tube runs uninterrupted to below the seed bearing structure, ie the ovary), but basically you have 4 petals + 4 attached stamens.

Now the main differences between the genera relate to the seed and/or, the seed bearing structure, which with Conospermum is a hairy obconical seed/nut. Conospermum in Latin means a cone [shaped] seed.

Therefore both these very different looking plants, have with close examination, 4 petals + 4 attached stamens + obconical seed/nuts!

Why not checkout the above features on the Proteaceae plants in your garden or bush? Then look at the different seeds and seed carrying arrangements. So now you should be able to recognise any Proteaceae plant from anywhere in the world, even if you have never seen them before.