Cyathium, the astounding performer

“What is the cyathium, this astounding performer?” wondered León Croizat in his “On the classification of Euphorbia” (1937).

The (literally) most beautiful Euphorbia, E. pulcherrima (from the latin pulcher / pulcherra = beautiful; pulcherrimum / pulcherrima = the most beautiful), stars in this festive season. It seems to be therefore an appropriate occasion to unfold the Euphorbia topic.

The story of E. pulcherrima begins from a very far distance to Christianity or Christmas traditions. The plant is native to Mexico, and has been well known to the Aztecs who used it to make red dye and as a fever cure.

Wild Euphorbia pulcherrima in Mexico.
Picture: Mark E. Olson

It was only in 1825 that it was first brought to the US by the ambassador Joel Roberts Poinsett – hence their common name, Poinsettia. Its undeniable extravagance due to the vibrant contrast between the intense red bracts and the deep green leaves rapidly made E. pulcherrima a popular species in horticulture. Being a December bloom, it soon became a favourite in Christmas decorations, which very much increased its popularity.

Joel Roberts Poinsett

The structure of Euphorbia flowers is a trend topic in botany classes because of their striking strangeness. This striking strange appearance is assigned to their being strikingly simple and complex at the same time. Euphorbia flowers are actually too simple to be called complex for the complexity does not lie in the flower itself, but on the organization of flowers within the inflorescence. It is so exquisite and unique that they gained a name for themselves – cyathium.

The structure of Euphorbia cyathium
Source: Euphorbiaceae.org

The cyathium is derived from a cymose-type inflorescence, and consists of a terminal female flower surrounded by prophylls (bracteoles) subtending the male flowers and forming the involucrum. Each flower consists of a single organ, so female flowers consist of a single pistil with the very typical 3-locular ovary (three carpels) and bifid styles, and male flowers consist of a single stamen. As there are no petals or sepals associated to the flowers, the cyathium develops bracts (cyathophylls) and large nectar glands for pollination purposes.

Cyathium of Euphorbia pulcherrima. Picture: Marc Perkins

But the cyathium structure is itself diverse, after all Euphorbia is a huge genus with around 2500 described species scattered around the globe (!!) – no wonder diversity is enormous. Some species (e.g., E. milii) have single cyathia with their own cyathophylls (two per cyathium). Others (e.g., E. albomarginata) have glands with petaloid appendages, resembling the classic structure of angiosperm flowers. E. pulcherrima, on the other hand, forms synflorescences, which in botanical language simply means a group of inflorescences (botanists really fancy throwing complicated names just because). So, E. pulcherrima forms cyathia lacking cyathophylls, which are grouped in synflorescences; therefore the red bracts so characteristic of poinsettias are not cyathophylls. Some authors don’t even consider these as being bracts, but simply as leaves that turn color, so you may find them described as bracteate leaves…

Left picture: Euphorbia milii (Source: Subhin)
Right picture: Euphorbia albomarginata (Source: Jason Penney)

I could continue endlessly writing about Euphorbias, but before getting too extended on the subject, I shall stop this post at once to wish all readers a fantastic holiday and a 2016 blooming with happiness.

Picture: Pauline Brock

The Passion flower

What is the first think you think of when someone mentions passion? Perhaps romantic love? Physical or sexual attraction for someone, or maybe just sex? Do you think of the same meaning of passion when the subject is the passion vine? What is the origin of this plant’s name? Is the passion fruit an exotic aphrodisiac? Well, not exactly but maybe if you’re in the right mood anything can work as an aphrodisiac...

Passiflora (Passifloraceae), the genus of the passion vine, gained this name due to the great imagination and devotion of the Portuguese and Spanish Jesuits which associated most morphological characters of the plant to symbols of the Passion of Christ. While exploring the exotic tropical rainforests of South-America they were astonished not only by the beauty and diversity of the plant (Northern-Central Brazil is an important hotspot of diversity for these plants) but also with all the symbolism that they immediately attributed to the plant. For the Jesuits, the flower of the passion vine had all the symbols of the Passion of Christ, and so it was named after this passion, not any other romantic or sensual passion that people might probably think of – after all it is indeed an exotic and extremely sweet fruit.

Flower diversity in Passiflora sp.

So now you are curious about the symbols, and the Jesuits were indeed very attentive – they looked at all the flower organs finding explanations for numbers and shapes of most of them. Let’s see…

The flower is pentamerous, with 5 sepals and 5 petals, representing the 10 faithful apostles (excluding Peter, the denier and Judas, the betrayer); the corona represents the crown of thorns with which roman soldiers crowned him as the “King of the Jews”; the ovary, a chalice shaped structure, represents the Holy Grail; the 3 stigmas represent the 3 nails used in Christ’s crucifixion and the 5 anthers the 5 wounds (1 in each hand and foot and the last one in his chest caused by the Holy Lance). But not only the floral structures were considered to be the symbols of the Passion of Christ. The characteristic leaves with pointed tips resemble the Holy Lance that confirmed Christ’s death and the tendrils represent the whips during the flagellation. The colours have also been attributed a meaning, since many species are white and blue colors, representing heaven and purity, and we must not forget the purple, which was also the colour of the robe that romans covered Jesus after crowning him.

The association between the flower and symbols of the Passion of Christ

Apart of all the symbolism involving the plant, there are also interesting characters related with the ecology of the plant that I would like to share with you. Every single part of it is edible, meaning that this plant is the herbivore heaven! They can eat the leaves, tendrils, flowers and there is plenty of nectar in the floral and extra-floral nectaries. To avoid getting eaten by all the herbivores, Passiflora seem to have made a deal with the ants by feeding them with nectar from extra-floral nectaries (usually present in bracts but also in leaves). Likewise, the ants protect their plant from herbivores and nectar robbers. Also the ants allow true pollinators to access the floral nectaries, allowing the successful reproduction of the plant. It sounds beautiful, but it is not as simple as it might sound – it relates many ant species, so a lot of different behaviours with different Passiflora species and environments. In any case, Passiflora and ants seem to get along very well and it seems to be a fair symbiotic relationship.

Ants feeding on nectar from extra-floral nectaries of the bracts of Passiflora

After attributing so many symbols to this plant, I wonder what Jesuits thought noticing so many ants around the vines getting rid of the hungry predators, protecting their “holy” source in exchange of precious nectar. I will let you meditate on this, wishing you a blessed Thursday of Corpus Christi.

The Tết’s flower

Have you been looking at the moon? It’s getting smaller and smaller and smaller…The New Moon is coming very soon, and so is the Lunar New Year! To celebrate this very special date, I will dedicate a post to a very special flower used in the Vietnamese (and maybe in other nations?) traditional celebrations of the Lunar New Year, or “Tết”. The first time I saw these flowers was here in Thailand and they kept my attention because of weirdness of their looks...

What else can I say? It looks just weird to me!

Since the first time I saw this flower I wondered to which family it belongs to, but the morphological clues didn’t ring me any bell - at all! I had no idea about the family of this plant. Until one day, when my Vietnamese herpetologist friend suggested me to talk about one of the most famous plants in Vietnam – Ochna integerrima. I was very much surprised when I realized that it was the flower I was wondering about for so many weeks! Thank you in advance for this, Ha. 

Ochna belongs to its own family, Ochnaceae and no wonder I could not identify this family – I have to admit I knew very little about Ochnaceae until now! But now I can say that I know little enough to dedicate one entire post to these flowers. Ochna integerrima is the most celebrated plant in Vietnam, because it blooms during the Tết, having a special meaning for Vietnamese culture. The Vietnamese believe that these bright yellow flowers bring luck and prosperity for the coming year.

Source: http://www.freephotos.biz

Another curiosity about this plant came up while I was googling “Ochna integerrima”, coming up automatically “Vietnamese Mickey Mouse Plant”… This common name made sense to me as I had seen the plant already, but for those who have never seen or heard about it before it might sound strange. This plant produces some beautiful round-shaped black berries on a bright-red head-like receptacle. So probably, some cartoon-lover botanist saw Mickey Mouse’s ears on the berries and decided to name it this way!

Fair enough!

After what happened I had to search about this family and will give you now some tips so we can all easily identify Ochnaceae. No more excuses! The flowers are usually pentamerous, having 5 sepals (usually enlarging in fructification) and 5 free petals (often caducous). The number of carpels is variable, sometimes fused having a terminal style, or if free with a gynobasic style.

Unfortunately, I didn’t find any flower with the petals as they are caducous and I only found later stages, already forming fruit

So now that we all know how an Ochnaceae flower looks like, I would like to wish you happy celebrations for those who celebrate. For those who do not usually celebrate, I suggest you to spend some time looking at the sky for a change, trying to find the New Moon!

Happy Lunar New Year everyone! =)

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 19^th 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.