Leaf of the Day: The Ballistic Bauhinia Pod

While looking at the Bauhinia trees last week I noticed that the ground around one tree in particular was covered with many pieces of curled seed pod and little disc shaped seeds. I do like seed pods and so I brought a few bits and pieces back. Most of them were in separates halves but this one was complete albeit without its seeds. On returning to the apartment I left them in a bowl water to clean them up a bit and to get rid of a few unwelcome bugs. When I later retrieved them, my lovely curly pods had flattened out completely but, of course, as they gradually dried so they curled up again demonstrating very nicely the “ballistic” method of seed dispersal.

The long flattened seed pods of this bauhinia apparently have layers of woody fibres which are laid at an angle to the edges of the pod. As the pods ripen and dry, the fibres pull against each causing extreme tension until the pod fractures explosively from the tip down, causing the the two halves to corkscrew, firing the seeds off to find their fortune elsewhere.
In this ballistic method of seed dispersal, the bauhinia is something of a champion, the exploding pods able to throw the seeds as much as 50 feet.

Of course for a big tree like this bauhinia it makes sense to get your offspring as far away as possible so as not to compete for space and food.
I have friends who would really like to employ this effective technique to encourage some their long term, stay at home children out into the world!


Bauhinia Pod

Leaf of the Day: Bauhinia Assorted

While I was at Leu Gardens the other day I noticed a little grove of bauhinia trees, they really are so pretty. I had drawn one leaf on the 22nd January post, here with some general background information. I loved the elegant shape and they were very new to me then.
Here at the Gardens, there must be six or seven varieties in the group, differing widely in the size and shape of their leaves and in the colour and structure of their flowers.
I have recently come across a charming book by a Mrs D V Cowen “Flowering trees and shrubs of India” published in the 1950’s. It seems that Mrs Cowen was a naturalist and artist and painted not only flowers but birds too, illustrating books by the great Indian ornithologist Salim Ali. I intend to find out more about her, but here is a short extract from her book plus her illustration of the purple and variegated Bauhinias.

“…Edging the golf course of the club was a glorious sweep of glowing purple. Even before I was near enough to identify the trees, the rich, heady perfume which filled the air told me they were Bauhinias. The sight left me breathless and it was then I realised how difficult was the attempt I was making to describe in mere words the trees I know better how to paint…” (“Flowering trees and shrubs of India”)

As ever, I am interested in the leaf shapes.. they are quite different but all with the distinctive bi-lobed leaf construction.
Here are six of the varieties with their flowers.

Bauhinia Divaricata, Elegant leaves with pointed lobes.

Bauhinia bowkeri… A more rounded leaf and first found by a Colonel James Henry Bowker (1822-1900), in the Eastern Cape. The Afrikaans name beesklou (cattle foot) is applied to most of the bauhinias and refers to the resemblance of the leaf the cloven footprints of cows.

Bauhinia grandidieri… A tiny leaved dwarf bauhinia tree.

Bauhinia galpinii … A more rounded leaf shape with very prominent veins and red flowers

Bauhinia travapotensis… A very large leaf with these beautiful spidery white flowers.

Bauhinia yunnanensis … A tiny twining vine from Yunan in southwest China with pink orchid-like flowers veined with purple.

These super photos are from the Florida Flowering Tree Society website

One interesting thing about these leaves is at the base of many is a small arc shaped structure a ‘pulvinus’ ..L. pulvinus: cushion, pillow. Described as “a group of cells at the base of a leaf or petiole that in certain plants by rapidly losing water, brings about changes in the position of the leaves.
This explains why, when I got the leaves home, some of them had folded in half only to open out again in water. The mimosa (sensitive plant) has the same mechanism for folding its leaves if touched or injured.
I had made some little drawings of the folded leaf in the first post.
The bauhinias also have interesting seed pods.. tomorrows drawing.

Bauhinia Assorted

Leaf of the Day: Bauhinia or Butterfly Tree

On the nearby charmingly named Gay Rd is a small retirement complex and this lovely tree must bring delight to whichever lucky resident has an adjacent room. I am presuming, from this leaf, that it is the Bauhinia purpurea: Purple Orchid-Tree
This genus of tree was named to honor the work of the Bauhini brothers, 16th century Swiss botanists and herbalists who each wrote extensively on horticulture and the use of plants.
There are many varieties of Bauhinia and in India, the Apta, as it is known, is celebrated both in myth and for its medical uses especially in ayurvedic medicine. In legend, the tree was showered with gold during a fight between Kuba the god of wealth and King Raghu. I think that is a very beautiful image and one of the observances of festival of Dussehra is the exchange of Apta leaves as a symbol of a gift of gold.

Leaf Description
This beautiful leaf is bi-lobed, so really made up of twin leaflets, joined in the middle and I have seen other examples that are more deeply divided. The interesting shape also earns it the name butterfly tree or more prosaically, cow’s foot. I have a proper botanical description of these leaves from the AgroForestryTree Database
“Leaves have minute stipules 1-2 mm, early caducous; petiole puberulous to glabrous, 3-4 cm; lamina broadly ovate to circular, often broader than long, 6-16 cm diameter; 11-13 nerved; tips of lobes broadly rounded, base cordate; upper surface glabrous, lower glaucous but glabrous when fully grown”

And I am learning more about the taxonomy of plants too.. so here, for the scholarly, from the USA Department of Agriculture is the correct classification for the lovely butterfly tree.
Kingdom: Plantae ( plants)
Subkingdom: Trachebionta (Vascular plants)
Superdivision: Spermatophyta (Seed plants)
Division: Magnoliophyta (Flowering plants)
Class: Magnoliopsida (Dicotyledons)
Subclass: Rosidae
Family: Fabaceae (pea)
Species: Bauhinia purpurea (butterfly tree)

There is so much to learn and understand… what joy!____________________________________________

The Butterfly Tree