Begonia's Hawaiian Cousin

Photo by Forest and Kim Starr licensed under CC BY 2.0

Begoniaceae is a strange family. It consists of two genera - Begonia, which comprises roughly 1,400 species, and Hillebrandia, which consists of a single species endemic to Hawai'i (Symbegonia has since been placed back into Begonia). Although I adore the entire family, its that single genus that is the focus of our attention today. Far from being a strange one-off, Hillebrandia has a fascinating evolutionary history.

The sole species, Hillebrandia sandwicensis, is the only member of the family native to Hawai'i. It differs from the genus Begonia in characters such as its petals, which are more numerous and more differentiated, its ovaries, which do not completely close, as well as various morphological characteristics of its fruit and pollen, which I won't go into here. It occurs naturally only on the islands of Kauai, Maui, and Molokai where it inhabits wet ravines in montane rainforest zones. Nowhere is this species considered abundant. 

Since its discovery in 1866, H. sandwicensis has been the object of much curiosity. Where did it originate? How old of a species is it? How did it get to Hawai'i? Thanks to some molecular work, a few of these questions are becoming a bit more clear. For starters, we can now confidently say that Hillebrandia is a sister lineage to all other Begonias. This in turn has provided a crucial step in our understanding of its biogeography.

Photo by John Game licensed under CC BY 2.0

Molecular dating techniques place the genus Hillebrandia at about 51–65 million years old, much older than any of the Hawaiian islands. As such, it is likely that this lineage is not the results of an adaptive radiation like we see in most of the archipelago's flora and fauna. Instead, it is now believed that H. sandwicensis is the only known relict species in Hawaiian flora. In other words, the ancestor of H. sandwicensis did not arrive at Hawai'i and then evolve into the species we know today. Instead, it is more likely that the lineage arose elsewhere and then, through a random long-distance seed dispersal event, made it to Hawai'i's oldest islands some 30 million years ago and has been island hopping to younger islands ever since. 

Although its recent history and geographic origins are still open to much speculation, the story of this unique genus has gotten a bit clearer. Its status as Hawai'i's only known relict plant species is quite exciting to say the least. What we can say for sure is that its history was likely full of serendipity that should be celebrated each time someone has an encounter with this lovely Hawaiian plant.

Photo Credits: [1] [2]

Further Reading: [1]

Pseudoanthry

I learned a new word today - "pseudoanthery." This term applies to a structure or organ on a nectarless flower that mimics a dehiscent anther. To elaborate further, a dehiscent anther is one in which a capsule containing pollen breaks open to reveal the pollen inside. For example, think of the anthers of an Asiatic lily. Back to the topic at hand.

I quite like learning new things, especially as it applies to familiar friends. I was admiring the floral display of a rather tall cane begonia when a friend of mine came up to me and simply said "pseudoanthery." I didn't quite catch it the first time so I asked him to repeat it. It wasn't hard to guess the root meaning of the word - fake anther. Confusion set in when I pointed out that I was looking at the female flowers of a begonia. Thus, a teaching moment presented itself.

Though I adore Begonias and have a small handful growing in my house at all times, I never stopped to think much about their pollination. Without a doubt, they can be quite showy. Even the smaller species can put on quite a floral show. Rarely have I ever detected a scent from a Begonia bloom, nor have I ever detected nectar (though that's not to say either of those qualities don't exist). The point I am trying to make is that I couldn't quite figure out their strategy.

Sure, male flowers contain copious amounts of pollen. That is incentive enough to visit a male bloom. But what about the female flowers? Do they get away with not offering any sort of reward by simply being showy? Certainly that helps, however, female Begonia flowers sweeten the ruse with a bit of mimicry.

That is where the term pseudoanthery applies. Take a close look at the stigma of a begonia flower and you will be marveled by its intricate structure and bright coloration. As it turns out, the stigma is shaped in such a way as to mimic the pollen covered anthers of male flowers. Insects looking for protein rich pollen with visit the female flowers, realize it was all for naught, and move on. That is all the female flowers require. While the insect was busy searching for pollen, it is very likely that the bristly hairs on the stigma were able to pick up pollen grains from the insect's previous visit. With a little luck, that flower was a male begonia.

This ruse works best at large numbers. By producing lots of male flowers and considerably fewer female flowers, Begonias can ensure that the insects are not deterred by the lack of rewards. This has a double benefit for the plant as female flowers and seeds can be costly to produce.

Quite fascinating if I do say so myself. I have looked at countless Begonia flowers and not once did I question their structure. Just goes to show you that even old friends can teach us new things.

Further Reading: [1] [2]

The Darth Vader Begonia

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Cue the Imperial March, it is time to talk about the Darth Vader Begonia. This atramentous plant had only been known to the world since 2014. The discovery of this species (as well as two other new Begonia species) occured in Sarawak, on the island of Borneo. This region is a hot spot for plant diversity and this is especially true for begonias. A combination of diverse terrain and varied microclimates have led to an explosion of speciation events resulting in endemic species found nowhere else in the world.

With its leaves so deeply green that they almost appear black and deep red flowers it's not a stretch to imagine why this begonia has been named Begonia darthvaderiana. Until 2014, no one had ever laid eyes on this species, not even the locals. It was found growing in the deep shade of a forested cliff mixed in among other shade-loving vegetation. It is likely that the dark coloration of its leaves enables it to take advantage of what little sunlight makes it down to the forest floor.

Not long after its discovery was reported, something alarming happened. The so-called Darth Vader begonia began appearing for sale online. With a price tag of $80+, this is one expensive little plant. Apparently a plant poacher from Taiwan managed to smuggle some plants out of the country. This is especially upsetting because of its extreme rarity. Despite its namesake, the force is not strong enough to protect this species from greedy collectors. If you have somehow managed to obtain one of these plants, please do everything in your power to propagate it. Plants produced in captivity take pressure off of wild populations.

This was not the only new begonia species to be named after a Star Wars character. A larger species with green and silver leaves was given the scientific name of Begonia amidalae after Queen Amidala. It too is endemic to the region. The future of these plants as well as many others hangs in the balance. A growing human population is putting pressure on the rainforests of Borneo. As more and more forest is lost to development, countless endemic species are disappearing with it. This is yet another example of why land conservation is a must. Please consider lending your support to organizations such as the Rainforest Trust. Together, we can ensure that there are wild spaces left.

CLICK HERE TO HELP LAND CONSERVATION EFFORTS IN BORNEO

Photo Credit: Che-Wei Lin, Shih-Wen Chung, & Ching-I Peng

Further Reading: [1] [2]

 

Central America - Part 2: The Journey to San Vito

The sun was up and burning by 6 AM. We were sweating by the time we arrived at the bus station. I always over-pack. Always. My backpack was loaded with extra clothes and camera gear. Luckily we were in store for a 6 + hour bus ride. The night before didn't do much in the way of helping me catch up on sleep. Alajuela is a loud city. It seemed like none of the cars had mufflers. Every passing hour came complete with multiple car alarms as well. Despite our exhaustion, we were excited to be catching the bus to San Vito. 

We first had to catch a bus into San Jose. It was an interesting process. It was a weekday morning and we quickly got caught up in rush hour traffic. Walking was easy. It would seem that driving in this country takes a whole new set of skills that I simply do not have. There are no street signs and everyone seems to follow some unwritten Darwinian traffic code - only the strongest survive. Trucks and buses move in and out of tiny, crowded streets without hitting the cars sandwiched in between them. Motorcycles and mopeds weave their way through what little space remains. Watching this unfold was an experience unlike anything I had ever encountered. I would surely crumble under these conditions. My pampered American ways had no place on these roads. 

We managed to find the first bus. What should have been a 15 minute commute from Alajuela to San Jose was actually going to be about an hour. Luckily I found myself sitting next to a man names Carlos. His English was perfect, probably better and more formal than my own. Carlos could certainly sense how out of place I was and was kind enough to strike up a conversation. As it turns out, Carlos is a plant scientist working at an agricultural research institute in San Jose. His work centers around making Costa Rican farming more sustainable. His current project involved introducing new potato varieties from Peru into the mix to help transition away from monocultures. 

We talked for a while about his approach to this but his concerns seemed daunting. Like everywhere else in the world, Costa Rica is facing an uncertain future with climate change. Areas that once sustained certain types of farming are no longer able to do so. He made sure to point out every farm along our rout and explain to me what was obviously wrong - huge, chemical-laden coffee plantations, timber lots chock full of invasive eucalyptus trees, and almost no erosion control anywhere, which is clogging up tropical streams with an endless supply of runoff and sediments. 

I could have talked to Carlos all day, however, we had to part ways. I was lucky to have met him. We grabbed a cab to the next bus station. Yet another awkward ride ensued as the kind cab driver did his best to speak in slow, easy Spanish. Within an hour our bus had arrived. We boarded with only a handful of other people. From what I have come to understand, there are two main routs from San Jose to San Vito - one takes you through the mountains and the other takes you down the coast. With my face glued to the window, it soon became apparent that our driver was taking us through the mountains. 

Like a kid in a candy shop, the scenery had my complete attention. The combination of the size of the bus and the elevation that we had to climb meant that the ride was slow enough that I could actually do some botanizing from the window. Again, I had almost no idea what I was seeing. The only plants I was remotely able to recognize were some sort of Dicranopteris fern that covered exposed roadsides and plenty of bamboo orchids (Arundina graminifolia), a species that has naturalized throughout the tropics but was originally native to parts of Asia. The rest quickly became a green blur of tree ferns, palms, and other tropical looking trees. I couldn't wait to explore with someone who knows a thing or two about Costa Rican flora.

We actually made good time considering the length of the trip. In just under 6 hours we were walking down the main path at the Wilson Botanical Garden. Here we were to meet our friend Dave. We found him watering some cacti. Though this was technically the rainy season, they had not received any rain in over a week. Some of the plants didn't quite know what to do. We found our sleeping arrangements for the next few days and were anxious to start exploring. The main grounds of the garden were jaw droppingly gorgeous. There was more plant diversity within a stones throw than anywhere else I have ever been. Dave had some work to finish up so he gave us a map of the grounds and sent us on our way. 

Being completely new to this area, I was a bit wary of what I might encounter. Does Costa Rica have its own tropical version of poison ivy? Was I going to brush up against or touch something that would result in a rash? I asked Dave if there was anything I should avoid and he had only one response, caterpillars. "Don't touch any of the caterpillars. Some can totally ruin your day." Noted. 

Being much closer to the equator than New York, we had to get used to the sun schedule. It starts getting dark around 6 during this time of year and we didn't want to be out unsupervised after dark. We kept our musings to the immediate area near our cabin. A friend joked that going to a botanical garden in a rainforest is kind of like going to a zoo in Africa. Though it was a funny comparison, it couldn't be farther from the truth. The beauty of the Wilson Botanical Garden is that it allows you an up-close and personal look at the flora. Sure, there are paths and labels but these are a great place to familiarize yourself with some of the local species before setting off blindly into the jungle. Begonias and gesneriads carpet walls and rocks, Palms offer shade for ferns and orchids alike. Countless endemic bird, insects, and amphibians haunt these grounds. We even saw our first wild agouti. I was both overjoyed and overwhelmed. 

As if on cue, it happened. We rounded a bend and dangling off the side of a tree was an orchid in full bloom. It was Gongora armeniaca. I never really understood what it meant to be speechless until this moment. In fact, I don't think my brain could fully comprehend what it was seeing. The long inflorescence was in full bloom. Each of its strange flowers were perfect. I have seen Gongoras before as curiosities tucked in the back of orchids rooms at various botanical gardens. However, nothing comes close to seeing a species like this in situ. I was going to have to pay a lot of attention to trunks and branches if I was going to see more botanical wonders like this.