Asteraceae – Don't hold your breath

Making it interesting

Symmetry is over rated. “Was it a car o” What’s that you say, a palindrome? Oh then did you mean “Was it a car or a cat I saw?” If something is symmetric, you need to see only part of it. The rest is implied by symmetry. The leaf in the featured photo looked perfectly symmetric, so how should I present a photo? I decided to go with the rule of thirds, and put the backbone to one side. You don’t have to see both halves of the leaf to imagine how lovely the leaf looks. But the truth is, it is a slight lack of symmetry which makes the photo interesting.

When I saw this Angled Pierrot (Caleta decidia) hanging below a leaf one morning I decided not to wait for it to spread its wings. The patterns on the two halves of its body are identical, and a photo with closed wings is enough to let you identify it. It was happy to play along by presenting only one antenna to me. But it didn’t manage to place both hindwings identically over the forewing, so you can see two of “tails”, the little bits of the hindwing which jut out. More broken symmetry; will nature never be perfect?

And the moon? Gravity pulls the larger moons and planets into visually perfect spheres. No natural object that you photograph will be as perfectly a sphere as the moon. But even there, if you look carefully, you’ll see craters and mountains on the surface. You may call them blemishes, but they are what gives it that look of yoghurt setting slowly in a bowl, releasing bubbles as it forms. I love those blemishes.

And then there is hidden symmetry! This lovely eight-petalled daisy called me to take a photo. Eightfold radial symmetry, is it? No, it was a complex flower like any in the aster family (Asteraceae). Which meant that each flower is actually an inflorescence fused together. Eight of the outermost flowers, the ray florets, give rise to the large showy petals. The rest, the disk florets, are clustered together into the eye at the center. There, in the eye, you can see one flower has opened up and shows clearly the fivefold symmetry underlying the complex flower. If you turn the flower over and look carefully at the bottom with a scalpel and magnifying glass in hand, you’ll see that the ray florets also have the same fivefold symmetry,

Islamic art of the 16th century CE developed a fascination with interlocking and hidden symmetries. The example on the left is a pattern from the dome of Humayun’s tomb in Delhi, designed by Mirak Mirza Ghiyas. On the right is a pattern from the central arches of Mihriman Sultan Mosque in Istanbul, designed by the Turkish polymath Mimar Sinan. The two are nearly contemporary: the tomb in Delhi completed in 1558, and the mosque in Istanbul in 1570. The artists know that symmetry is a wonderful organizing principle, but somewhat boring. So they hide other things inside the outer pattern: flowers and leaves in one case, calligraphic writing in the other.

This post is scheduled to appear while I travel. I’ll reply to your comments and look at your posts when I have network coverage.

Edelberg’s cotton thistle

Butterflies I can usually identify quickly. This was an Indian cabbage white (Pieris canidia). Plants are harder. The flower was definite in the family Asteraceae, containing asters, daisies, and sunflowers. I could go further; this was clearly a thistle. It was probably a cotton thistle. There aren’t so many of them, so I could patiently sit with my photos in front of me and try to identify which it was. I’d not neglected to take a photo of the leaves this time, and the “sketch” shows the lobed leaves with their spiny thorns. The single flower heads, the shapes of the flowers, the leaves, all pointed to this meter high plant as being Carduus edelbergii, Edelburg’s cotton thistle. I was at an altitude of about 3000 meters, in Hunder in Ladakh. That’s in the middle of the plant’s range. This wasn’t so hard to identify after all.

A history of brief time

Camphorweed (genus Pluchea) or Blumea? Or some other flower altogether in the family Asteraceae of asters, daisies, sunflowers, and nettles? Whatever it is, it has a brief flowering season at altitudes of about 2 kilometers above sea level. That’s why a photo of a single panicle captures flowers at all stages of their brief, umm, flowering. I liked that; a single photo to show time passing.

Even at these lower heights of Ladakh, rain clouds are stopped by the Himalayas in the south and the Karakorams in the north. In this high desert, plants have evolved to conserve moisture. One of the ways they do it is by not opening up wide like a daisy.

A surfeit of daisies

A steep bank across the road from the gate of the bungalow we stayed in near Ooty was covered with low herbs, many in flower. I spent a couple of wonderful mornings peering at them and taking photos. Among the hardest to identify are the various plants in the Aster family, Asteraceae. All have complex flowers like daisies and sunflowers. They have big showy petals around the edge and a dense cluster of tiny flowers at the center: the ray florets and disk florets respectively. The two flowers shown in the featured photo are Mexican fleabane (Erigeron karvinskianus, also called daisy fleabane) and are a common weed found in disturbed ground, or in cracks of walls. The inset shows a straggling stalk and the lance shaped leaves.

This one is also in the aster family, probably a Bidens pilosa, called variously Beggar tick or Kumur (in Hindi). It became a widespread weed after its accidental import from the Americas to the tropics around the world. The flowers develop into fruits with burrs which stick efficiently to our clothing, and to mammalian fur. It is this method of dispersal which has allowed it to become a common flower across India (and large parts of the world). I should remember to take a macro of the burr the next time I have to pick one off my clothes. What I remembered to get this time was a photo (from which the “sketch” is generated) of the cluster of hairy serrated leaves at ground level from the middle of which a bare stalk rose to hold the flower where flying pollinators could settle on it.

This post is scheduled to appear as I travel with limited access to the net. I will try to look at your comments and reply when I have a chance.

Some budding daisy

Who can keep track of all the flowers in the family Asteracea? There are 24,000 or more species in the family to which daisies and sunflowers belong. You can recognize one by their complex flowers, consisting of large petals surrounding a disk of tiny flowers (the ray and disk florets, as they are called). The ray florets are each an individual flower which have merged into the complex. So it was easy to figure out which family the bud belonged to. But more specifically what was it? I could see the hairy lance shaped leaves, surrounding a thick hairy centimeters high stalk from whose tip the buds sprouted two by two (see the accompanying “sketch”). The bud was less than a centimeter tall. There were no open flowers that early in July near the bungalow in Ooty, but even if I’d found an open one I would probably only have called it a daisy-like flower. Can you help with the ID?

An octoploid

If dahlias grew in New England and behaved here as they do in Mexico, we would surely regard them as weeds.
Paul D. Sorensen (The Dahlia: An Early History)

During its cultural evolution from a source of food in Mexico, on account of its tuberous roots, to its prominence as an ornamental plant in modern day gardens, the Dahlia has passed through an enormously complicated process of breeding. When I walked through a garden last weekend, the variety of colours of Dahlias was stunning. In the middle of March the weather has turned unpleasantly warm, so the flowers had started wilting. Still, I hadn’t seen a Dahlia this year until then, so I took photos. What makes the Dahlia a breeder’s pet is that it has four pairs of each chromosome (unlike our two), and the chromosomes are full of jumping genes. Even though this anemone-flowered Dahlia does not have disk florets like a normal member of the Aster family (Asteraceae) it has tube shaped flowers in the center and the usual long flat ray florets outside.

Walking near the Periyar river

Periyar river, the lifeline of Kerala. It was a name that fascinated me. A simple name, meaning big. That’s all that the people around it need to know. But the river rises in the biodiverse Western Ghats, and in the short 244 Kms from its source to its mouth in the Arabian sea it traverses a wide range of altitudes. So, almost exactly five years ago we took a short trip to the Periyar National Park. We landed at the Kochi airport and took a bus to our destination. The road passes through the intensely urbanized plains. But then, as we crossed a bridge over the river, the urban clutter fell off. We’d reached our homestay, a small two-storeyed house near the entrance to the park.

We dropped our bags and headed out for a walk. There is always a lot to see just outside a national park. We walked back to the bridge we’d crossed. Power lines ran next to it and we were sure to find kingfishers and bee eaters perched there, at eye level. I had my big lens with me, but I’ll show here only those photos I took with the fixed lens of my cell phone. The river branched crazily here, as it reached the plains. A boat was tied next to a little side stream that we crossed. A group of langurs chattered madly as they ate leaves in the canopy of trees around the path.

The phone was also good for close ups. Here in the undergrowth is one of the numerous species that you could call a daisy. I love their complex flowers, five white ray florets and numerous five-petalled yellow florets in the disk. The arrangement of the disk florets and their shape should be a very good guide to a more precise identification, but I’m intimidated by the size of the family Asteraceae, the asters. Full identification is a finicky and time-consuming job.

Which trees grow here? The answer is plain when you look around you. But it is equally plain when you look down at the small landscape around your feet. A large leaf from a teak tree was flaking into pieces as it dried. I pointed my phone at it. Bamboo too, as you can see. And the small leaves of, what was it, jamun? Quite a variety. It would be hard to keep the jamun from being eaten by birds and langurs. But then those trees fruit so abundantly that you can always get enough. We reached the bridge, and then it was time for the big zoom and the end of my fixed-lens adventure.

Common thistle

Did you know that thistles are in the same family as daisies? I found that unbelievable at first: the cheerful white and yellow daisies which dot sunny meadows cousin to the thorny thistles which brood in dark open spaces under trees? But then I considered the evidence. Like their other cousins, the asters and sunflowers, both are complex flowers. There are the colourful petals surrounding a distinct center. When you look at the center, you find them full of complete tiny flowers called the disk florets. The circle of “petals” around this disk are each a flower, a ray floret, which has given up its identity by fusing into a larger structure. There are other commonalities, but this observation began to break down my initial disbelief.

I’ve usually seen them under dense growths of pines or deodar (cedar) which dot Himalayan grasslands, in places where the sunlight does not reach easily and other flowers shun. I suppose these are its refugia, safe places, where humans don’t hunt them down. They do not actively shun sunlight, because they can grow also in farmlands, but they are usually evicted quite quickly from there. Maybe they need some open space around the base, which is why they do not grow where the grass is dense. I’ll have to look more carefully at its base in future.

But was this particular plant a common thistle (Cirsium verutum) or Wallich’s thistle (Cirsium wallichi)? The flower head is not sufficient to clearly distinguish the two. I had to look at the leaves and the stem. The common thistle has leaves which end in a long spine, with other spines along the lobes on the sides. Wallich’s thistle has a less pronounced terminal spike and a hairy stem. So I think this was Cirsium verutum, the common thistle.

Tridax daisies

After yesterday’s broad look at the Aster family, I stepped closer to look for plants that I could identify. The Tridax daisy (Tridax procumbens) is the one I recognize quickly in the field. It has five ray florets, each such “petal” is deeply notched to give it the appearance of three fingers. The main reason I learnt to recognize it is because the straggling stems with upright flowers can be seen across India. Now, near Dotiyal village in Kumaon, about 2700 m above sea level, I was happy to meet a familiar face.

The featured photo is not of a flower that helps identification, since it has lost its characteristic ray florets . But I liked the way the dew had collected on it. Other flowers were more easily identified. But in the process of taking those flowers, I have caught a fly which I can’t identify. If you are a fly fancier, could you help?

One large happy family

Asters, that’s who mean. The family Asteraceae contains well over 30,000 species. In one small place, around the little Nal-Damayanti Tal in the lake district of Kumaon were these seven species. Some were fleabanes (both seem to belong to the genus Erigeron), two look like daisies, and three I cannot really place.

How do I know they belong to the Aster family? Because they can be identified by one simple feature: they have compound flowers. At the center of each compound flower is a disk, filled with tiny flowers. These are called disk florets. Larger petals surround the central disk. Each petal is an individual flower, called a ray floret. The disk and the rays are often different colours. If this reminds you of sunflowers, daisies, gerbera, or chrysanthemum you are right. They are all part of the same family.

There are no true daisies (genus Bellis) in India. So these must be something closely related, perhaps true asters? I always wondered if there are so many asters in the world, why haven’t we tamed many of them into edible plants, like we have done to grasses. I looked it up today, and it seems that asters do not store energy in starch but in what we would think of as dietary fiber.

Almost three quarters of Asteraceae belong to a subfamily called Asteroideae, which contains most of our garden flowers. I think it means that the two flowers in this bunch which look like daisies could be the most difficult to identify. The rest should be relatively easy. Any guesses? As the Terminator said, “I’ll be back”, to write down the identifications of these seven in full when I get them.