Colourful leaves

Calla lily, Poinsettia, Bougainvillea. Three of the plants in which people sometimes mistake leaves for flowers. Gardens and hedges in Mumbai are full of the splashy colours of Bougainvillea right now. But the colourful stuff isn’t petals, they are just the leaves surrounding the true flower. The youngest niece asked me, “What’s the difference?” Well, the petals unfurl from inside the bud, but the bracts, these differently coloured leaves, develop from the stem just as normal leaves would do. Hers was a deep question if I read it differently. One parts of the “abominable question” of the rise of flowering plants which exercised Darwin was the origin of petals. Are they modified leaves, or modified stamen? Modern methods are beginning to answer this question, but the understanding can change yet. Current opinion leans towards petals rising from bracts.

In our balcony I caught the bracts in the middle of changing colour. In the featured photo you can see the green stalks of the buds just about to open into tiny flowers. The leaves around them have started losing their chlorophyll. The transformation has progressed further in the leaves closest to the bud. A few of the leaves in this cluster are more green, presumably having started the transition later. Further back in the same branch you see a small cluster of leaves which have just begun to turn colour.

Just for fun, here is another of my experiments with black and white. This time I wanted to get the difference in texture between the leaf and the bract, and colour distracts from texture. I’m happy to have caught this plant at the right time.

We don’t see the world as it is …

Someone said something like “We don’t see things as they are, we see them as we are.” Who? A search, filtered through my web bubble, ascribed it to Stephen R. Covey, Anais Nin, Albert Einstein… The trail is complex enough that the Quote Investigator has an article on it. When you start thinking about the path from the the eye to the perception of the world around us, you realize that the world is so complex that the brain’s computations can only create an approximation. A frog sees a world of moving objects in exquisite detail. A butterfly sees the bright patterns in ultraviolet light that flowers have evolved to attract them. We do not. And the camera, that instrument that we carry around in our pockets, does not see what we see. So it takes a little work to tweak a camera’s output to get the impression of dark water, its surface reflecting the clouds above, its transparency letting you see a rotting leaf slowly sinking, its beading on the fresh leaf to reflect the sun, into what you think you see.

The cold war led to the development of CCDs to act as eyes on spy satellites. In the same year, 1976 CE, that they were first used for this purpose, they were also used for astronomical observations. The very next year they were put into the Voyager satellites, our first eyes to travel to other planets. Kodak labs had developed the first CCD camera in 1975, but it wasn’t till 1988 that the first commercial digital camera became available. There is enough information in the output that what looks like a perfectly black image at first can be used to tease out details. Even without using raw data, I could recover an image of a gaur (Bos gaurus) that I saw on a dark night in a forest. You see that imposing creature in the photo above. This was an old camera, so there is a lot of noise, but I like it that way. After all even our eye/brain does not see too well in the dark.

Colour perception is another whole kettle of fish. The simple RGB colour space model which cameras use is a very crude approximation of what our eye sees. Actual human colour perception is still an active research area. So the images that come out of a camera require colour correction. And the interaction of attention and colour; let’s not even go there. When I looked at this lotus pond inside a forest my first reaction was to the bright red of the flowers. Only later did I realize that the number of insects on it was enormous. And was the water strider (Gerridae) there for the flower, or its shade? I forgot all about the red. To reproduce a semblance of this attention I had to tweak the photo.

Lens artists will want to see the” originals” too. The step from raw to jpeg is all digital magic, so nothing is really original. For that matter, our eyes are not particularly great instruments, so the brain’s chemical-electronic magic is really needed to build up, see, the world around us.

Gratuitious photo

A walk in the garden on Perihelion Day was a bit of a disaster. In most years this is the best time in the garden in Mumbai. This year the pandemic meant delays in turnover and replanting. As a result, the garden was mostly freshly turned beds. Only one row of plants was flowering, the lilies that you see here. Backlit, I wonder which version looks better, the colour or the monochrome. What do you think?

A silver-lining in a man-made ecology?

I wanted to demonstrate to The Family that my vision had not improved after my surgery. I nodded at the trees on the ridge half a kilometer above us. “I was able to see those white flowers more clearly before,” I said. She was surprised. “I hand’t seen them.” She raised her binoculars to her eyes as I took a photo. My eyes were truly bad. Those weren’t flowers, just the white underside of the silver oak (Grevillea robusta) leaves, as the wind ruffled its canopy. We laughed at that, my point made. Thank you, unknown colonisers who disrupted the ecology of this ridge in the mid-19th century CE, barely a decade after the discovery of these pseudo-oaks in eastern Australia, by planting them across the Deccan plateau.

Invaders are usually bad, but the silver oak, planted right across India and Kenya, have been generally regarded as benign. They do not immediately have an advantage in competition with local plants. They provide shade and support for multi-culture of pepper in coffee plantations (these British colonial-era plantations devastated the ecology of the Nilgiris). In Kenya they are used very similarly, and also provide useful hard wood in regions that lack them. Newspapers carry happy reports of their integration into the local ecology. Through Africa there are studies of increased productivity in agro-forestry when silver oak is used to provide a high canopy. However, new elements are always disruptive. It is a second host for the mealy bugs which infest mango trees, and can act as reservoirs for the pest. What seems to be a good neighbour one century can turn out different in another. The story of silver oaks in Asia and Africa is still beginning.

Three wildflowers

When the known walks are crowded you just have to find new places to walk in. In the slight drowsiness of a post-lunch discussion, we did not really think this through. So we set off along deserted roads, looking for small paths into the forests of the Mahabaleshwar plateau. We found one, parked on the side of the road, and set off along what looked like a tunnel between trees trodden out by many feet. It was in use. We saw discarded bottles of alcohol and cans of beer in little clearings off the main path, and not too much plastic. One of the first things I saw were the purple heads of Indigofera cassioides (चिमनाती, pronounced chimnati) in flower. I have seen this flower before, but it took a little consultation with Ingalhalkar’s book and a cross check with IndiaBiodiversity to reach an ID. Some other day I’ll talk more about the indigo plants.

I misidentified the yellow flowers of Mysore thorn (Cesalpinia decapetala, also Biancaea decapetala) when the oldest niece asked for an ID. I have been set right by Ingalhalkar and CABI. This is a firm ID I think, it takes into account the flowers, the leaves, and the fact that the widespread plant was a climber. I have no ID for the white flowers. Can anyone help?

This is only a small sample of the flowers and plants we saw on the walk before we met a villager coming down the path. He warned us that leopards are seen here often. As we walked on, the chatter of the nieces decreased in volume. Then there was a crashing noise in the trees and everyone wanted to turn back. On the way back we heard more crashing noises and then saw a monkey leaping between branches. It was clearly not a leopard hunting. I argued that leopards are known to be very secretive stalkers, and monkeys are known to give alarm calls when they see predators, so we were quite likely to be safe. But the group had given up, and we were out near our car soon. Later I thought that if everyone who had come for a holiday up here had decided to take a walk in the woods for the next few months there would not be much of a forest left in a few years. In a way it was good that the villagers put us to flight.

Behind the Chinese knotweed

I saw a flowering bush growing wild by the edge of the road, so I walked out to it. I thought I recognized Chinese knotweed (Polygonum chinense or Persicaria chinensis). It was. The flowers are distinctive, and I think I may be able to tell it even by the shape of the bushes. I’ve written a bit about it after the first trip to the Sahyadris when I learnt to identify it. The amazing group of plants, these knotweeds, diversified in just the last 10 million years and spread out from the Tibetan plateau along the arc of the Himalayas. But this species probably established itself in these hills long after humans came here. I wonder whether old documents or field techniques can date their arrival in this general location. But whenever they came here, they rapidly became the go-to plant for a large number of pollinators. The famous Mahabaleshwar honey seems to have quite a bit of Chinese knotweed pollen in it.

The photo shoot was over pretty soon, but I was intrigued by a path which led beyond these bushes. I followed it, and it soon arrived at the edge of a cliff, with a nice view down to the valley below. The variety of plants was staggering, especially when you consider that this is degraded area, close to a high-traffic road. I looked down at the valley, and for fun took a trio of photos at different zooms of the village I could see.

Unknown wildflowers

It feels odd to slip into a piece on unknown wildflowers of the Sahyadris with a the very common and widespread weed, lantana. They were introduced into India during the British period, escaped, and have now become great butterfly magnets. This species, the Lantana camara, is identifiable by the colours which give it its common name, Spanish flag lantana. As children we would pick the ripe black berries on these bushes and eat them by fistfuls.

But immediately after that I jump to species that I do not know. The Sahyadris are under constant surveillance by botanists and wildlife experts, so I’m sure that these species can be easily named by many. Unfortunately, I’m not a member of that smart set. Ingalhalikar’s three volume Flowers of Sahyadri is extensive, but unfortunately not useful as a field guide. So, all you trekkers, and amateur naturalists out there, I need your help with identification and suggestions for field guides.

Awn, glume, culm, rachis

It was winter when I first passed through the Sahyadris, many decades ago. I looked out of the window of a train at the amazing landscape: fantastic rock shapes covered with swathes of drying grass. Those expanses of drying yellow grass have drawn me out of the city year after year. From a distance you see hills covered by trees, but when the rock falls away too steeply for a tree to find stability, grasses cascade over the steep slopes, in shades of yellow, gold, or red. I’ve always wondered about the varieties of grass that one can see. Now, in the infrequent outings during the pandemic, I thought I would learn how to tell grasses apart.

Starting is never easy. I looked at books and guides, and wondered at why I never took to botany. I looked at the lovely words: rhizome, culm and spikelet, rachis, glume, awn and floret, bulb and crown, sheath, blade, ligule and auricle. I could hypnotize myself with words like this, fall in love with language. But in school, when I tried to study botany, I would open the books too late, and the words would become a wall I could never be able to climb. I never mastered the words, and never managed to look out at the vista of the subject from the top of that high wall. One learns a technical language to be able to read and understand others, not to create barriers for others. Now that I have all the time in the world, here are some notes to myself. In the analogy that I have drawn, the rest of this post is a set of spikes driven into the wall so that I can climb it quickly later. If you enjoy it, so much the better.

I am not about to become a late-flowering botanist, so I will not look at the structure below the ground: the root and the modified stem called the rhizome. All that I’ll need to know is that if the rhizome is present, then the grass is a perennial. The stem is what I start from, and that should be called a culm by people like us who want to know more about grass. The culm could have a part below the ground, called the rhizome, but I will learn about the stolon, which is the part above ground. Some stolons, like the ones in these photos, stand upright, but others, for example on the lawns outside my apartment, trail on the ground. Stolons have nodes, and leaves or roots can arise from these. These nodes are called crowns when leaves arise from them. If a grazer eats a culm, it is regenerated from a crown. The leaf is another thing to look at. Its sheath wraps around the culm; if the blade bends away from the culm, then you can see a little tongue near the bend. This is a ligule; and it prevents insects from crawling down the blade into the sheath to eat away at the culm.

The most interesting part of a plant is the flower, the floret is what you would call it if you are a grass gazer. Grasses are wind pollinated, and do not require the petals which other plants use to attract pollinators. The florets are held on a part of the stem called the rachis; it may be straight or branched. The flowers are contained in spikelets. At the base of the spikelet, close to the rachis, are two modified leaves called glumes, which hold the florets alternately along their length. The tips of the glumes are extended into the long pointed things called awns, which you can easily see in all the photos here.

I love awns; they are what made me take the photos.

Flowers wake

I was extremely surprised when I realized that feral okra (Abelmoschus esculentus, aka bhindi) grew widely near the seashore around Mumbai. By most accounts, this plant originates in north-east Africa, and spread from there to South Asia and Arabia in prehistoric times, and then to the rest of the world in the modern era. There are several closely related edible plants, which seem to have been hybridized extensively over millenia and are genetically almost indistinguishable now. It is a bit surprising to find that it is as hardy as a weed, and grows in most unused land around the city. Perhaps the hot and wet conditions here suit it especially well.

This week, while watching birds around Bhandup pumping station, I spent a while looking at the flowers of this plant unfold in the morning. I had not realized that the flowers close at night, a behaviour called nyctinasty. Why would plants put on rapid bursts of growth at different parts of the petals at dusk and dawn to force the flower to open and close? There’s a lot of speculation about the function of nyctinasty in leaves. Okra leaves seemed to have remained open at night, so most of the speculations are ruled out. Since the leaves were dripping water at dawn, I guess the main function of the closing of petals must be to keep the sexual organs dry. Interesting that this question does not seem to have been investigated before.