The Traveler's Palm

© CEphoto, Uwe Aranas licensed under CC BY-SA 3.0

This nifty looking tree is commonly referred to as the traveler's palm (Ravenala madagascariensis). In reality, it is not a palm at all but rather a close cousin of the bird of paradise plants (Strelitziaceae). It is endemic to Madagascar and the only member of its genus. Even more fascinating is its relationship with another uniquely Madagascan group - the lemurs. But first we must ask, what's in a name?

The name "traveler's palm" has two likely explanations. The first has to do with the orientation of that giant fan of leaves. The tree is said to align its photosynthetic fan in an east-west orientation, which can serve as a crude compass, allowing weary travelers to orient themselves. I found no data to support this. The other possibility comes from the fact that this tree collects a lot of water in its nooks and crannies. Each of its hollow leaf bases can hold upwards of a quart of rain water! Get to it quick, though, because these water stores soon stagnate.

Photo by H. Zell licensed under CC BY-SA 3.0

Flowers are produced between the axils of the leaves and closely resemble those of its bird of paradise cousins. Closer observation will reveal that they are nonetheless unique. For starters, they are large and contained within stout green bracts. Also, they are considerably less showy than the rest of the family. They don't produce any strong odors but they do fill up with copious amounts of sucrose-rich nectar. Finally, the flowers remain closed, even when mature and are amazingly sturdy structures. It may seem odd for a plant to guard its flowers so tightly until you consider how they are pollinated.

It seems fitting that an endemic plant like the traveler's palm would enter into a pollination syndrome with another group of Madagascar endemics. As it turns out, lemurs seem to be the preferred pollinators of this species. Though black lemurs, white fronted lemurs, and greater dwarf lemurs have been recorded visiting these blooms, it appears that the black-and-white ruffed lemur manages a bulk of the pollination services for this plant.

Watching the lemurs feed, one quickly understands why the flowers are so stout. Lemurs force open the blooms to get at the nectar inside. The long muzzles of the black-and-white ruffed lemur seem especially suited for accessing the energy-rich nectar within. The flowers themselves seem primed for such activity as well. The enclosed anthers are held under great tension. When a lemur pries apart the petals, the anthers spring forward and dust its muzzle with pollen. Using both its hands and feet, the lemur must wedge its face down into the nectar chamber in order to take a sip. In doing so, it inevitably comes into contact with the stigma. Thus, pollination is achieved. Once fertilized, the traveler's palm produces seeds that are covered in beautiful blue arils.

Photo by Jeffdelonge licensed under CC BY-SA 3.0

All in all, this is one unique plant. Though its not the only plant to utilize lemurs as pollinators, it is nonetheless one of the more remarkable examples. Its stunning appearance has made it into something of a horticultural celebrity and one can usually find the traveler's palm growing in larger botanical gardens around the world. Though the traveler's palm itself is not endangered, its lemur pollinators certainly are. As I have said time and again, plants do not operate in a vacuum. To save a species, one must consider the entirety of its habitat. This is why land conservation is so vitally important. Support a land conservancy today!

Photo Credits: [1] [2]

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

A Bat-Pollinated Passion Flower From Ecuador

[SOURCE]

Say "hello" to one of Passiflora's most recent additions, the bat-pollinated Passiflora unipetala. The first specimens of this vine were discovered back in 2009 by Nathan Muchhala while studying flower visiting bats in northern Ecuador. It is a peculiar member of the genus to say the least. 

One of the most remarkable features of this plant are its flowers. Unlike its multi-petaled cousins, this species stands out in producing a single large petal, which is unique for not only the genus, but the whole family as well. The petal is quite large and resembles a bright yellow roof covering the anthers and stigma. At the base of the flower sits the nectar chamber. The body of the plant consists of a vine that has been observed to grow upwards of 6 meters up into the canopy.

[SOURCE]

Flowering in this species occurs at night. Their large size, irregular funnel shape, and bright yellow coloring all point to a pollination syndrome with bats. Indeed, pollen of this species has been found on the fur of at least three different bat species. Multiple observations (pictured here) of bats visiting the flowers helped to confirm. Oddly enough for a bat-pollinated plant, the flowers produce no detectable odor whatsoever. However, another aspect of its unique floral morphology is worth noting. 

The surface of the flower has an undulating appearance. Also, the sepals themselves have lots of folds and indentations, including lots of dish-shaped pockets. It is thought that these might help the flower support the weight of visiting bats. They may also have special acoustic properties that help the bats locate the flowers via echolocation. Though this must be tested before we can say for sure, other plants have converged on a similar strategy (read here and here).

As it stands currently, Passiflora unipetala is endemic to only a couple high elevation cloud forests in northern Ecuador. It has only ever been found at two locations and sadly a landslide wiped out the type specimen from which the species description was made. As such, its introduction to the world came complete with a spot on the IUCN Redlist as critically endangered. Luckily, the two localities in which this species has been found are located on privately protected properties. Let's just hope more populations are discovered in the not-too-distant future.

Photo Credits: [1] 

Further Reading: [1]

The Grasstree of Southwestern Australia

Taken by John O'Neill licensed under CC BY-SA 3.0

Southwestern Australia is home to a wonderful and unique flora. A combination of highly diverse, nutrient-poor soil types, bush fires, and lots of time have led to amazing adaptive radiations, the result of which are myriad plant species found nowhere else in the world. One of the most incredible members of southwestern Australia's flora is the grassplant (Kingia australis). Like all plants of this region, it is one hardy species.

The taxonomic history of the grassplant has been a bit muddled. As its common name suggests, it was once thought to be a type of grasstree (genus Xanthorrhoea), however, its resemblance to this group is entirely superficial. It has since been placed in the family Dasypogonaceae. Along with three other genera, this entire family is endemic to Australia. Growing in southwestern Australia presents lots of challenges such as obtaining enough water and nutrients to survive and for the grassplant, these have been overcome in some fascinating ways.

The way in which the grassplant manages this is incredible. Its trunk is not really a true trunk but rather a dense cluster of old leaf bases. Within this pseudotrunk, the grassplant grows a series of fine roots. Research has shown this to be an adaptation to life in a harsh climate. Because water can be scarce and nutrients are in short supply, the grassplant doesn't take any chances. Water hitting the trunk is rapidly absorbed by these roots as are any nutrients that come in the form of things like bird droppings.

Photo by Casliber licensed under CC BY-SA 3.0

Coupled with its underground roots, the grassplant is able to eek out a living in this dry and impoverished landscape. That being said, its life is spent in the slow lane. Plants are very slow growing and estimates place some of the larger individuals at over 600 years in age. Its amazing how some of the harshest environments can produce some of the longest lived organisms.

As you can probably imagine, reproduction in this species can also be a bit of a challenge. Every so often, flower clusters are produced atop long, curved stems. Their production is stimulated by fire but even then, with nutrients in poor supply, it is not a frequent event. Some plants have been growing for over 200 years without ever producing flowers. This lifestyle makes the grassplant sensitive to disturbance. Recruitment is limited, even in good flowering years and plants take a long time to mature. That is why conservation of their habitat is of utmost importance.

Photo Credits: [1] [2]

Further Reading: [1] [2]

Enigmatic Neviusia

Photo by Philip Bouchard licensed under CC BY-NC-ND 2.0

Neviusia. The first time I heard it mentioned I was certain the conversation had switched from reality to the world of Harry Potter. I was wrong. The name belongs to a genus of plants that are totally real. What's more, the natural history of this small group is absolutely fascinating.

The genus Neviusia is comprised of two extant species. N. alabamensis is endemic to a small region of the southeastern United States around northwest Georgia and the Ozark Mountains. Its cousin, N. cliftonii, was discovered in 1992 and is endemic to a small area around "Lake" Shasta in California. Fewer than 20 populations have been found and of them, six were flooded to create "Lake" Shasta. It would seem very strange that both species in this genus are not only endemic to extremely localized regions but also completely disjunct from one another. This is only the beginning.

Whereas fruits have been described for N. cliftonii, none have been reported in N. alabamensis. Ever. Thanks to genetic analysis, populations of both plants are thought to be entirely clonal. High rates of pollen sterility are to blame. Why this is the case is hard to say. It is thought that the genus Neviusia is a relict of the early Cenozoic. Fossil evidence from British Columbia suggest that this genus was once more diverse and more wide spread, having gradually declined to its current limited distribution. The Pleistocene was likely the last straw for these plants, being corralled into small refugia of suitable habitat by the glaciers. Lack of seed production (perhaps due to genetic drift) meant that these two species were to never recolonize their former range. At least not without help...

Since their discovery, these two species have garnered some attention. Like Franklinia, Neviusia have become a sort of horticultural curiosity and have since been out-planted in a variety of locations. My first and only encounter with Neviusia occurred in a conservation garden. Despite their popularity among researchers and gardeners alike, it is unlikely that Neviusia will ever reclaim even a fraction of their former glory. Instead, they remain as endemic reminders of a bygone era. Despite their limited range I think it is important to remember just how long they have survived in North America. After millions of years of survival and persistence, their biggest threat is now us.

Photo Credit: Philip Bouchard (http://bit.ly/1WpElzX)

Further Reading:
http://bit.ly/1NqFdlq

http://bit.ly/1ZFEa1G

http://bit.ly/1UT2WfF

http://bit.ly/24OshNM

http://bit.ly/1TFblOd

http://bit.ly/1rWecMq

An Endemic Houstonia

Photo by BlueRidgeKitties licensed under CC BY-NC-SA 2.0

The weathered peaks of the Southern Appalachians are home to a bewildering variety of plant life. This region is thought to have provided refuge for many different types of flora and fauna pushed south by repeated glaciation. High humidity and precipitation coupled with a variety of microclimates has allowed plants to flourish and evolve over the millennia. In fact, a handful of species are found nowhere else in the world. One of these montane endemics is none other than a species of Houstonia. 

Some feel it best designated as a subspecies, Houstonia purpurea var. montana, whereas others feel that both morphological and reproductive distinctions deserve it a status as its own species, Houstonia montana. I prefer to refer to it as the Roan Mountain bluet. Either way, this unique little plant can be found  growing among rocky summits and balds on only a handful of mountain tops between Tennessee and North Carolina.  

This species requires disturbance to survive. Without the constantly shifting landscape characteristic of high altitude regions, this little plant would quickly be overtopped and outcompeted by more aggressive vegetation. This is not a lifestyle unique to this little bluet. Many of the worlds rare plant species require some level of disturbance to release them from competition with other more common plant species. Aside from competition, one of the largest threats to the continued survival is trampling by hikers. It is always important to watch where we hike. A little bit of attention can go a long way for our botanical neighbors. 

Photo Credit: BlueRidgeKitties (http://bit.ly/1dJ7SkA)

Further Reading:

http://www.esajournals.org/doi/abs/10.1890/1051-0761(1998)008%5B0909:PORPOA%5D2.0.CO%3B2

http://www.bioone.org/doi/abs/10.3159/1095-5674(2007)134%5B177:GOTRSA%5D2.0.CO%3B2

http://link.springer.com/article/10.1007/s10682-011-9539-x#page-1

http://www.jstor.org/discover/10.2307/4032597?uid=2&uid=4&sid=21106703459663

Sandfood

Photo by USFWS Pacific Southwest Region licensed under CC BY 2.0

Photo by Don Davis licensed under CC BY-NC-ND 2.0

Pholisma is yet another amazing genus of parasitic plants. Endemic to the southwestern United States and Mexico, these peculiar members of the borage family tap into the roots of a variety of plant species. They do not photosynthesize and therefore obtain all the nutrients they need from their hosts. Oddly enough, researchers have found that most of their water needs are met by absorbing dew through the stomata on their highly reduced, scale-like leaves. Water is then stored in their highly succulent stems. Throughout their limited range, Pholisma are critically imperiled. Development and agriculture have already eliminated many populations. To add insult to injury, the dunes in which most extant populations are found are owned by the BLM and are open to heavy off-road ATV traffic, which will likely push them to the brink of extinction if nothing is done to limit such recreational use. Unless people speak up about protecting these plants and their habitats, they could disappear for good.

Photo by Vijay Somalinga licensed under CC BY-NC-ND 2.0

Photo by Vahe Martirosyan licensed under CC BY-SA 2.0

Photo Credits: [1] [2] [3]

Further Reading: [1] [2]

Carnivores in Amber

Carnivorous leaves from Eocene Baltic amber. (A) Overview of the leaf enclosed in amber showing the adaxial tentacle-free side in slightly oblique view and stalked glands at the margin and on the abaxial side; arrowhead points to the exceptional long tentacle stalk with several branched oak trichomes attached. (B) Overview of the leaf enclosed in amber, showing abundant tentacles on the abaxial side. (C) Margin of abaxial leaf surface with tentacles of different size classes and nonglandular trichomes [SOURCE]

Carnivorous plants are marvels of evolution. Adapting to nutrient poor conditions, these botanical curiosities have evolved myriad ways of capturing and digesting prey. For all of their extant diversity, the fossil record of carnivorous plants over the eons is pretty much non existent save for some highly contentious fossils from China as well as some fossilized seeds of the aquatic carnivore, Aldrovanda. However, a recent discovery out of Russia changes everything. Beautifully preserved in amber, we now have the first conclusive fossil evidence of a carnivorous plant.

The amber was found in a mine in Russia and is estimated to be between 35 and 47 million years old, during an epoch known as the Eocene. Inside are beautifully preserved leaves of what seems to be a species of Roridula. The leaves clearly show specialized stalked glands with a pore at the tip. The researchers who discovered the amber also found evidence of the sticky secretions that were used to capture its prey.

Overviews showing the tentacle-free adaxial surface and tentacles along the leaf margins (B & C). (D) Partial leaf tip showing different size classes of stalked glands. [SOURCE]

The resemblance of these leaves to the leaves of extant Roridula is uncanny. Modern Roridula do not directly digest their prey. Instead, they rely on a symbiotic relationship between a species of bug, which lives on the leaves without getting stuck. The bugs hunt down and eat trapped insects. As they eat, the bugs defecate and it is their nitrogen-rich feces that the plants absorb for sustenance. It is quite possible that the fossilized Roridula also relied on these insects as well, though no direct evidence of this was found. 

The most interesting aspect of this discovery is its location. Today, Roridula is found only in South Africa. Its presence in Russia hints at a historic distribution that is much wider than previously thought. It has long been assumed that Roridula is a neoendemic to South Africa, with the family having arisen there and nowhere else. This discovery now shows Roridula to be a paleoendemic, once having a much wider distribution but currently restricted to South Africa. This discovery is an excitingly huge step in our understanding of carnivorous plant evolution. 

Morphological comparison of the carnivorous leaf fossils from Baltic amber (Left) and extant Roridula species (Right). (A and B) Leaf tip ending in a sole tentacle. (C and D) Stalked glands of different size classes. (E and F) Hyaline unicellular nonglandular trichomes. (G and H) Epidermal cells and stomata. (I–L) Multicellulartentacles. (A, C, E, and G) (I and J). (B, D, K, and L) R. gorgonias. [SOURCE]

Photo Credit: Alexander R. Schmidt, University of Göttingen

Further Reading: [1]