The Plight of the African Violets

Photo by RobertoMM licensed under CC BY-SA 3.0

Photo by RobertoMM licensed under CC BY-SA 3.0

For many of us, African violets (Saintpaulia spp.) are some of the first houseplants we learned how to grow. They are not true violets (Violaceae), of course, but rather members of the family Gesneriaceae. Nonetheless, their compact rosettes of fuzzy leaves coupled with regular sprays of colorful flowers has made them a multi-million dollar staple of the horticultural industry. Unfortunately their numbers in captivity overshadow a bleak future for this genus in the wild. Many African violets are teetering on the brink of extinction.

The genus Saintpaulia is endemic to a small portion of east Africa, with a majority of species being found growing at various elevations throughout the Eastern Arc Mountains of Kenya and Tanzania. Most of the plants we grow at home are clones and hybrids of two species, S. ionantha and S. confusa. Collected in 1892, these two species were originally thought to be the same species, S. ionantha, until a prominent horticulturist noted that there are distinct differences in the seed capsules each produced. Since the 1890's, more species have been discovered.

Saintpaulia goetzeana

Saintpaulia goetzeana

Exactly how many species comprise this genus is still up for some debate. Numbers range from as many as 20 to as few as 6. Much of the early work on describing various Saintpaulia species involved detailed descriptions of the density and direction of hairs on the leaves. More recent genetic work considers some of these early delineations to be tenuous at best, however, even these modern techniques have resolved surprisingly little when it comes to a species concept within this group.

Saintpaulia sp. in situ. Photo by TanzaniaPlantCollaboration licensed under CC BY-NC-SA 2.0

Saintpaulia sp. in situ. Photo by TanzaniaPlantCollaboration licensed under CC BY-NC-SA 2.0

Though it can be risky to try and make generalizations about an entire genus, there are some commonalities when it comes to the habitats these plants prefer. Saintpaulia grow at a variety of elevations but most can be found growing on rocky outcrops. Most of them prefer growing in the shaded forest understory, hence they do so well in our (often) poorly lit homes. Their affinity for growing on rocks means that many species are most at home growing on rocks and cliffs near streams and waterfalls. The distribution of most Saintpaulia species is quite limited, with most only known from a small region of forest or even a single mountain. Its their limited geographic distribution that is cause for concern.

Saintpaulia ionantha subsp. grotei in situ.

Saintpaulia ionantha subsp. grotei in situ.

Regardless of how many species there are, one fact is certain - many Saintpaulia risk extinction if nothing is done to save them. Again, populations of Saintpaulia species are often extremely isolated. Though more recent surveys have revealed that a handful of lowland species are more widespread than previously thought, mid to highland species are nonetheless quite restricted in their distribution. Habitat loss is the #1 threat facing Saintpaulia. Logging, both legal and illegal, and farming are causing the diverse tropical forests of eastern Africa to shrink more and more each year. As these forests disappear, so do Saintpaulia and all of the other organisms that call them home.

There is hope to be had though. The governments of Kenya and Tanzania have recognized that too much is being lost as their forests disappear. Stronger regulations on logging and farming have been put into place, however, enforcement continues to be an issue. Luckily for some Saintpaulia species, the type localities from which they were described are now located within protected areas. Protection coupled with inaccessibility may be exactly what some of these species need to survive. Also, thanks to the ease in which Saintpaulia are grown, ex situ conservation is proving to be a viable and valuable option for conserving at least some of the genetic legacy of this genus.

Saintpaulia intermedia [source]

Saintpaulia intermedia [source]

It is so ironic to me that these plants can be so common in our homes and offices and yet so rare in the wild. Despite their popularity, few recognize the plight of this genus. My hope is that, in reading this, many of you will think about what you can do to protect the legacy of plants like these and so many others. Our planet and the species that call it home are doomed without habitat in which to live and reproduce. This is why land conservation is an absolute must. Consider donating to a land conservation organization today. Here are two worth your consideration:

The Nature Conservancy

The Rainforest Trust

Photo Credits: [1] [2] [3] [4] [5]

Further Reading: [1] [2] [3] [4] [5]

Stained Glass Leaves

 

Producing flowers is a costly endeavor for plants. They require a lot of resources and give nothing back in the way of photosynthesis. The showier the flower, the greater the investment. It should be no shock then that some plants utilize more energy efficient strategies for attracting pollinators. One of the more interesting ways in which a plant has evolved to save energy on flowering comes from a rather surprising family. 

Gesneriads are known for their showy flowers. There are many variations on the theme but most are rather colorful and tubular. However, in the jungles of Central and South America grows two species of Columnea that make such generalizations a waste of time. The flowers of C. consanguinea and C. florida are small, drab affairs, especially for a Columnea. They arise from the stem at the base of the leaves and would largely go unnoticed without close inspection. It is amazing that anything could find them among the chaos of the jungle understory let alone pollinate them. That is where the leaves come in. 

Photo by alex monro licensed under CC BY-NC 2.0

Photo by alex monro licensed under CC BY-NC 2.0

Towards the tip of the long, blade-like leaves are heart shaped red spots. They are translucent and to stand below one conjures a mental image of stained glass windows. Against the background of greens, these spots really stand out. Their purpose is to attract pollinators, specifically the green-crowned brilliant hummingbird (Heliodoxa jacula), which can then locate the nectar-rich flowers, pollinating them as they feed. By producing these translucent red spots on their leaves, these plants are able to save a lot of energy. Leaves are retained for much longer than flowers are and, of course, they photosynthesize.

Photo Credit: Jardín Botánico Nacional, Viña del Mar, Chile (http://bit.ly/1CXtToh) and alex monro (http://bit.ly/1uVwf0x)

Further Reading:

http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2745.2008.01465.x/full