Begonia sizemoreae

A bit of Botany Photo of the Day news before today’s entry: the move to the new server is taking up a significant amount of time, hence the slowdown in entries. However, it seems so far to be resolving the partially-loading image issue during testing, so that alone will make it worthwhile. On a different note, my identification was incorrect on the previous entry, but it might take a little time before I can revise it.

Today’s entry was written by Claire:

Thank you to John B. (aka DCTropics@Flickr) of Washington, DC, USA for this lovely photo of a female flower of Begonia sizemoreae (Botany Photo of the Day Flickr Pool).

Only two genera occur in Begoniaceae: Begonia and Hillebrandia, the latter of which has a single species, Hillebrandia sandwicensis (endemic to Hawaii). Begonia has over 1,400 species and is found across the tropics in the Americas, Asia and Africa (but curiously, not Hawaii).

This particular species, Begonia sizemoreae, is one of over thirty validly described species in Vietnam though there are likely dozens more (ref: Dr. Ruth Kiew of Malaysia (if you are a reader interested in begonias, Dr. Kiew has a book out about the Begonias of Peninsular Malayasia).

Begonia sizemoreae, as shown in the photograph, is a monoecious species (having both male and female reproductive organs on the same plant), but is unisexual in that there are separate male and female flowers. Many of us are more familiar with bisexual flowers — individual flowers with both functional male and female organs. This mechanism Begonia sizemoreae utilizes discourages self-pollination and promotes outcrossing for genetic variability within the population of plants. On the particular flower in the photograph, note the four gorgeous, spiraled stigmas of the female reproductive organ. For pollinators, this presents a challenge as these non-rewarding features very closely resemble the rewarding, pollen-heavy anthers. The insect gets confused from this clever disguise, and in the course of visiting both male and female flowers, pollinates. J.G. in S.F.@Flickr took this photograph of a male Begonia flower from a different species, illustrating the similar appearance of the yellow stamems.

Additional characters of Begonia sizemoreae are visible in the photograph, such as the distinct hairs on the leaf margins that provoke the common name of Vietnamese hairy begonia. Another lovely feature of this species with great ornamental potential is the fruit–a winged capsule containing numerous tiny seeds (photograph also by John B.).

Begonia sizemoreae

5 responses to “Begonia sizemoreae”

  1. Shirley

    That is a begonia? It is absolutely gorgeous!

  2. Eric in SF

    I have Dr. Kiew’s Peninsular Malaysia book and it’s stunning. Definitely worth grabbing if one finds it out and about. I only wish I’d gotten it *before* my trip to Borneo.
    The hairy begonias are endemic to the entire region. Here is one from Mulu National Park, Sarawak, Malaysia, island of Bornoe:

  3. Elizabeth Revell

    I have to say I’m not surprised there are no Hawaiian species. Hawaii is more Oceanic than Continental. None of the other islands of Oceania feature Begonias either – except in cultivation of course! They are gorgeous, even those which are mainly coltivated for their foliage. I love them. They flower, and flower, and flower for months. Many of them even seem tolerant of neglect … a major reccommendation in my garden!
    And this one is a beauty. Are the leaves really as thick and “warty” looking as that one in the photo edge?

  4. Earl Blackstock

    What a beautiful photo of a absolutely stunning flower to start the morning. Thanks Claire and Daniel.

  5. Glade R. Player

    Great photo, I’ve always thought the interesting stigmas found in begonias were mimicing the anthers, trying to attract pollen collectors.

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