species hibiscus

[1.618]

Hi Charlie and all,

I enjoyed very much the article in the most recent HVH newsletter about lilliflorus and the related species hibiscus. Very interesting! I could not resist putting in my 2 cents here.

What I have learned in my readings about taxonomy (the sience of classifying animals and plants) is that certain characteristics are considered important to defining differences between species and other characteristics are not. For example if one plant had fleshy fruit and another had dry fruit that would be considered a very significant difference. However flower color is not a trait that would be considered significant. All species have some variability and flower color is a common variable in many plant species.

So after reading between the lines in your article my own interpretation would be that the Conservatoire Botanique National de Mascarin is probably correct to "refer to these species as being "synonyms" for each other" or at most subspecies since in other respects the flowers look very similar to me. Of course to be really certain would require very close and thorough examination of good material from all "species" first hand or a study of the genes as you pointed out later.

Ian

[Charlie]

Hi Ian,

Thanks for the thoughtful comments. As you noted, flower color is not necessarily that important a characteristic but it is a highly visible one that can help to quickly separate one specimen from another subject to closer examination. Currently I have 2 of the 4 species that are believed to originate on the Mascarene Islands - H fragilis and H liliiflorus. Although I can tell them apart on sight they do share a lot of characteristics such as thin and flexible stems and similarly shaped leaves. During the first few years they grow tall with lots of thin, willowy stems. It would be great to collect the other 2 - H genevii and H boryanus.  Comparing all 4 side by side would be an excellent way to see how closely related they are and from what I can see would be a service to the botanical world that so far has not done much to clarify the differences, if any. They may turn out to be more like the hibiscus species in Hawaii such as H arnottianus which have developed subtle differences after being separated on the different islands.

However, the genetic research also reported on did find differences in the species plants they looked at. H boryanus was quite distant from the others, relatively speaking. H liliiflorus and H genevii also gave different, but much closer results when genes were looked at.

It's an interesting topic, with work still to be done!

Charlie

[Charlie]

Another way to test whether a particular plant is a species like H liliiflorus rather than a hybrid is to pollinate some flowers of the plant with its own pollen. If seeds result then  they can be grown to maturity and compared to the original. If the plants grown from seed are different than the original then that tells us that the original plant in question is likely a hybrid and not a species, but if the plants grown from seed appear identical to the original this is highly suggestive that it is a species. I have recently done the first part of this with the pink flowered H liliiflorus and am waiting to see if the resulting seedpods give us viable seed. We will track the outcome of this project with photos as it progresses.

Charlie