Wednesday, 14 December 2011

A wee enigma as Christmas present

Dear readers, 

As I will be traveling for the next weeks I won’t be able to post any story, so I decided to challenge you with a little charade… Maybe easy for some of you, hard for others, but you should give it a try!
I wish you all a Christmas full of love and all my best wishes for the New Year!

Now, L’énigme :

In this crowded flower city…

…Marriages are of five husbands with two wives. Husbands and wives live together in the same house, sharing the room upstairs; they are only allowed to have one child, sleeping in a single room downstairs, next to an unoccupied room. Husbands hug together surrounding their wives.
Mistresses don’t get married; they live in big houses with open view, outside the crowded city center. Mistresses always share a double room with another woman.

Will be waiting for your guess

See you in 2012! =)

Tuesday, 13 December 2011

Sacred-lotus? HELP!

How could I live in South-East Asia without mentioning anything about Lotus?
The Lotus flower is one of the most popular flowers in South-East Asia, it is the national plant of India and Vietnam, and is also deeply related with the Thai culture – it is present in art, traditions, food but most important of all, in their religion. These flowers have a great symbolic value for the Buddhists as it is present in Buddha’s life in many episodes. The first episode is even before his birth, when Queen Maha Maya had a dream of a white elephant holding a white a lotus flower in its trunk and walked around her three times. This dream was the prophecy of the birth of Buddha. Another famous episode tells that when Buddha was born he did seven steps and at each step a lotus flower appeared on the ground. Also Buddha is many times represented sitting on a lotus blossom while reaching the enlightenment as lotus blossoms symbolize full enlightenment.

Lotuses have a handful of meanings in Buddhism and the different meanings depend on the colour of the flowers (white, red, blue, pink, purple and gold) but also on the developmental stage (closed lotus, growing lotus and blooming lotus). Among the many different meanings, lotuses usually come associated with purity and divine birth, especially the white lotus.
I could dedicate an entire post explaining the importance and the different meanings of sacred-lotuses in both Buddhism and Hinduism, but that is not my aim. Lotuses have their own story to tell…
For many years the true taxonomical identity of lotus was hidden, I mean they are not what they appeared to be and their looks fooled botanists for long time. Only on late 80’s – early 90’s with the new molecular techniques botanists found out the scandalous truth: lotuses are not related to water lilies! Water lilies belong to the Nymphaeaceae (Nymphaeales order), a basal angiosperm family; lotuses belong to the Nelumbonaceae (Proteales order) which is not only a different family, but also placed in a much derived group. In conclusion: lotuses (Nelumbo) are today considered to be more closely related with sycamores (Platanus) rather than water-lilies (Nymphaea), as they are placed in the same order (Proteales).

It is not surprising that experts were deceived by the lotuses morphology. Characters as massive flowers, indefinite number of petals in a spiral position and ascidiate carpels are usually associated with basal angiosperms. This added with the adaptations to the aquatic environment shared by both groups made botanists conclude that they were very closely related. Not the case at all! All these similarities were not evidence of a shared evolutionary history, but of a convergent evolution.

Nelumbo or Sacred-lotus (left) vs. Nymphaea or Water-lilly (right)

 But there is no need to despair – after this post there are no more reasons to mistake a lotus flower with a water-lily. The most conspicuous difference between these two is the carpel, which in Nelumbo is an expanded receptacle that contains the seeds when mature. There are also marked differences in the stamens, which are laminar, or in other words leaf-like in Nymphaea (another common character of basal angiosperms). In Nelumbo the stamens form a ring at the base and are filamentous. Finally, it should also be mentioned that even though they are both aquatic, Nymphaea always has floating leaves and in Nelumbo they are above the water, as well as the flowers.

Different floral stages of Nelumbo nucifera (Sacred-lotus)

 But although the taxonomy is solved, the confusion is still reigning amongst common mortals and water-lilies are still called lotuses by many people (including Buddhists). So let’s see Nelumbo nucifera is the well known “sacred-lotus” and has pink petals, however in Buddhism the different colours of the lotus are associated with different meanings. The other two species of lotus (N. lutea and N. pentapetala) are endemic to the American continent, so they can’t be related with Buddhist traditions. This means that the only lotus that can be associated with Buddhism is pink! So where do the other colours come from? Nymphaea of course! The number of species of Nymphaea is much superior and the colours of the flowers are also very variable.

Colour diversity in Nymphaea

 Confused? Yeap me too, so I will leave you with this: Are the different colours associated with water-lilies instead of the sacred-lotus? Or are the colours symbolic variations of the sacred-lotus?
Hopping that some of you have a clue that helps to clarify this!

Friday, 9 December 2011

A Mid-Night Horror Story

Imagine you’re walking around in the forest at night and suddenly you find a pile of thin bones, you look up and you see a tree with dangling sickles and bats flying over… Creepy, uh? Well, maybe if you look a little bit closer the bones are not real bones, they are fallen branches and there are no sickles, they are just the fruits of this bat-pollinated tree – but that was scary enough! Today’s story is about the “Midnight Horror”!
The midnight horror tree, Oroxylum indicum, is a very popular tree in Southeast Asia due to their weird appearance, but despite of this, there is no reason to fear it - in fact most of the plant is used for medicinal purposes (leaves, seeds, bark and roots).

Oroxylum indicum. On the left side: the tree with hanging fruits; on the right side: the flowers.
Oroxylum indicum belongs to the Bignoniaceae family, a family with tropical distribution, belonging to the problematic Lamiales order. Lamiales encomprises some closely related and big families such as Lamiaceae, Acanthaceae, Oleaceae, Gesneriaceae, Scrophulariaceae, Plantaginaceae, Verbenaceae… The relationships between these families are not well understood and in many cases the morphological characters are not strong enough to determine the families’ delimitation, especially floral morphology. The typical Lamiales flowers have a well developed and basally fused calyx, a monosymmetric bilabiate corolla (upper and lower lips) and a superior bicarpellate ovary.
*Wow, botanists’ sophisticated dialect alert!*
Ok, ok… It is easier if I show some pictures, but what I want to show you here are the fluctuations on the number of stamens.

Typical Lamiales flowers. On the left: Lamiaceae, upper lip formed by 2 fused petals and lower lip formed by 3 fused petals; Dashed line representing the monosymmetric corolla. On the right side: Orobanchaceae, upper and lower lips fused forming the corolla tube; the calyx is fused on the base. 

In Lamiales the androecium varies from one to five stamens, including reductions of stamens into staminodes (sterile stamens) which are not well understood. This character is highly variable, and in my opinion is due to the current evolution of the group. This means that the characters for families’ circumscription are not well established yet, giving this morphological fluctuation as a consequence.
However, Bignoniaceae, has some characters restricted to the family, which makes it easy to spot in the field. The flowers in this family are very big, colourful and showy – hard not to see. They usually also have big nectarines in the base of the flower, releasing a strong and sweet fragrance – no wonder they are pollinated by big animals such as bats! Usually they have 4 fertile stamens and 1 unfertile stamen (staminode), but this species in particular has 5 fertile stamens and no staminodes. I have also found Bignoniaceae flowers with more variation, but as I explained before, I believe the presence or absence of staminodes is possibly related with a transitional evolutionary state. The stigma (the female part which receives the pollen) is usually wet and relatively broad.

Typical Bignoniaceae flower with 2 pairs of stamens (long and short) and one staminode

 The essential vegetative character of the Lamiales is the simple-opposite leaves, but luckily Bignoniaceae has compound opposite leaves, and this makes our lives easier! Bignoniaceae are usually represented by trees, shrubs and are also well represented in tropical America by climbers, having the terminal leaflet differentiated into a tendril.
So don’t forget, whenever you see a tree or climber with big showy flowers with the petals fused into a tube, check for the leaves, if they are compound, you probably found a Bignoniaceae! In the case of the midnight horror tree, they have big white or whitish flowers, blooming and releasing a sweet scent at night – all perfect characters for efficient bat pollination.

Tuesday, 6 December 2011

Viola’s love story

Some of you might already know that my favourite flowers are probably Viola’s, however I never did any work or wrote anything about them – to be honest I don’t even know why they are my favourites. Personally, they do have a special meaning to me as Viola riviniana was the first plant I identified alone using a flora – this is a mark in a botanist’s life!

Viola riviniana
Viola’s have the cutest flowers on earth, and although this is a very personal opinion, many people had similat thoughts. Many of us know Viola’s as ornamental flowers – in fact their beauty also attracted gardeners since early 19th century. Many varieties of pansies (hybrids between Viola tricolor with other Viola species) were produced since then and today we have countless cultivars of the original pansy, but I do prefer the wild Viola tricolor. There is nothing like having wild Viola’s “staring” at us – they are lovely! To start with, I have to say that the Portuguese common name for Viola is “amor-perfeito”, meaning “perfect love”, but it is not only a Portuguese thing to think that Viola’s are so deeply related with love… Or is it a Portuguese thing to give attention to Viola’s love clues?
They are also famous by their sweet odor, especially Viola odorata, which is used in perfume industry. Not happy with being beautiful and fragrant they are also full of goodness! The entire plant is edible, and in Europe, violets are used to make popular spring salads. They also have being used with medicinal purposes in many cultures and for the most variable reasons since ancient times. Europeans, Asians and also Native Americans used to produce traditional medicines with Viola’s leaves and flowers. Homer said once that Athenians used Viola tricolor to temper the anger, but it is also used with many other medicinal purposes, including pain relief and heart problems. It is clear for me – it is used to cure love diseases! And in fact, Ancient Greeks considered the violet a symbol of fertility and love, using them in love potions... Can't be a coincidence.

Viola’s are mainly pollinated by bees, and this is easy to understand by looking at the flower features. The colors are mainly purple, but also yellow and white; the lines in the petals act as landing lines, indicating to the pollinator where the nectar can be found. One of the most characteristic features of Viola flowers is the presence of the spur – a structure that produces and stores the nectar. The pollinator must follow the landing lines to find the nectar in the spur, and by doing so, the pollen gets attached to its body – pollination succeeds again! The leaves of Viola are usually heart-shaped (how adorable is that?!), at least in the base of the plant.

 To finish with, I just want to make a small art reference I found about these loving flowers. Viola’s also inspired many artists (no wonder!), but I won’t bother you with a list of famous classic pieces. I just want to share this last curiosity about “Shakespeare in Love”, have you ever seen this film? It tells a fiction story of Shakespeare while writing his famous “Romeo and Juliet”, inspired by his muse, a woman named Viola – coincidence? In any case, if roses are for some the flowers of passion for some, violas are surely synonyms of pure & sincere love after this post.

Thursday, 1 December 2011

Marcgravia: the MacGyver of the flowers

"Oh I've heard about you! You're the guy who does the whatchamacallits, you know, MacGyverisms; turns one thing into another?"

Do you remember the American TV series MacGyver? The other day, by chance I found a very interesting paper published recently in Science explaining an amazing co-evolutionary event in a tropical plant, Marcgravia. After reading it, I automatically thought: Marcgravia is the MacGyver of pollination! Turns one thing into another… Want to know why?

Marcgravia is a plant genus belonging to its own hidden family, Marcgraviaceae, only found in the New World Tropics (Central and South America). The group is relatively small and the flowers not well studied. However, their inflorescences are pretty extravagant. The inflorescences consist on upside-down umbels with several flowers hanging down. The flowers have 4 or 5 petals fused together (characteristic of Ericales clade, where they belong to) and the number of stamens is highly variable and showy. Not a very exciting description, right? Yep, that’s because the excitement of these flowers remain on the bracts and bracteoles – and now you are asking: “What are those?”. Bracts and bracteoles (small bracts) are leaf-like structures associated with the inflorescences (bracts) and individual flowers (bracteoles). Bracts and bracteoles are sometimes associated with the protection of the flower, but in many cases they don’t have any particular function, so some plants might lack them. In Marcgravia we can find both structures and both of them have a good reason to exist. 

The bracteoles of Marcgravia are a piece of art! They were modified into big and exuberant pitcher-shaped nectaries, imagine big nectaries full of yummy nectar… Lucky pollinators! Oh yeah, and who pollinates these amazing flowers? Any guess? Well… It actually depends, but such big structures with large quantities of nectar are definitely not pollinated by invertebrates… They are pollinated by big animals, mainly humming birds and bats. Actually, the reason why I wanted to tell you this story is because of the amazing co-evolution of pollination between Marcgravia evenia and bats. Just like MacGyver, using common things to make complex gadgets, Marcgravia evenia also made quite a gadget with their bracts. How? By turning a boring leaf-like structure with apparently no use (the bract) into an echo-location device! 

The inflorescence bracts of Marcgravia evenia developed into a dish-like structure, guiding the bats in the forest into the inflorescences! The shape of the bract produces a strong and easily recognizable echo by the bats, making it easier for the bats to find the inflorescences. Once they find the inflorescence, they feed on the nectar inside the pitcher-like nectaries (the modified bracteoles); the hanging flowers (with numerous stamens which are full of pollen ready to be released) are strategically positioned, leaving the bat’s back full of pollen and this is how pollination happens in this species. Actually, this system is highly efficient, since the bats take only half of the time to find flowers with these bracts in comparison to other flowers without them. 

So Marcgravia is for me like MacGyver, turning things with no apparent use into very usefull ones: bracteoles into pitcher-shaped nectaries and bracts into echo-location devices… Isn’t Nature absolutely amazing?