Tag: summer

From “Pollen and Pollination” in Exploring Biology by Pamela S. Camp and Karen Arms:

“Pollen develops in chambers at the ends of the stamens. Just as leaf shape and flower structure vary from one kind of plant to another, so do the shape and pattern of the pollen grain wall. Experts can easily identify the genus of a pollen grain by its distinctive cell wall pattern….

“Pollination is the transfer of pollen to the stigma. Pollen cannot move on its own power. Plants rely on wind or animals as agents of pollination. Wind pollination is often wasteful because much of the pollen never reaches another flower. Pollination by animals may save energy on pollen production. An animal that visits only one kind of plant carries pollen directly from one individual to another of the same species. Animals that serve as pollinators include insects — bees, butterflies, moths, wasps, flies, and beetles — and vertebrates such as birds, bats, and even a South African mouse!

“How do flowers attract animal pollinators? First, there is an attention-catching advertisement, such as the odor, shape, or color of a flower-preferably all three. Second, there is some type of reward — usually a sweet nectar. The reward is so located that the animal cannot reach it without at the same time acquiring a load of pollen. All of this has a cost: the animal-pollinated flower must invest energy in making its nectar and its large, showy petals, even though it need not make the prodigious quantities of pollen required for successful wind pollination.”

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Hello!

This is the second of two posts with photos of Tiger Lilies (Lilium lancifolium) that I took in June of this year. The first post is Capturing the Elusive Tiger Lily (1 of 2), where I explored a Tiger Lily’s uncommon ability to create and dispense bulbils and produce exact copies of itself. Like most plants, though, members of the Lily species use more than one reproductive strategy — something we’ll discuss in this post while observing how the plant’s architecture supports its goal of enticing bugs, bees, birds, and butterflies to help it develop species longevity.

To start, let’s take a look at one of my photos from the galleries below, a macro image of the center of the flower’s structure. Here we see some of the Tiger Lily’s most striking visual characteristics up close: the contrast between its saturated orange color and the black (they’re actually combinations of very dark red and magenta) spots on each of its elegant recurved petals. The bright orange and the contrasting spots — easily seen from great distances — enhance the flower’s visibility to pollinators; while the recurved petals support the flower’s growth and reproduction strategies through their unique architectural construction.

Imagine if you took a piece of drawing paper and cut out a six-pointed star to simulate the appearance of this Tiger Lily, flattened. Now imagine drawing the points of your paper star upward, to curve and meet with a slight overlap at the center. You’d likely discover that keeping the “petals” of your paper star-flower in position wouldn’t happen on its own; you’d have to fasten them together with tape or staples. Yet the Tiger Lily accomplishes that shape and holds it throughout its blooming cycle, typically unaffected by any wind or rain that might batter it while it’s blooming.

Unlike your paper flower, you’d find it quite difficult to bend the Tiger Lily petals back to horizontal positions they would have briefly held before curving. This kind of structural tension represents a complex form of engineering on the part of the Tiger Lily, so I decided to ask my research assistant ClaudeAI to help me explain how the thickness of the petals and the raised ridges emanating from the center support the Tiger’s Turk’s Cap form. Here’s what I learned:

Your insight about the thicker petals and ridging at the center solving the structural challenges of the Turk’s cap form shows remarkable botanical intuition. Think of this like understanding how a cathedral’s flying buttresses work — the most dramatic architectural features require the most sophisticated support systems, often hidden from casual view.

When Tiger Lily petals curve backward into that spectacular recurved position, they’re essentially performing a complex feat of biological cantilever engineering. Each petal must support its own weight while curved dramatically away from its attachment point, creating what engineers call tension stress along the outer surface and compression stress along the inner surface. The thickened base you’ve photographed functions like the reinforced foundation of a cantilever bridge, providing the structural mass needed to anchor the entire curved structure.

The ribs or ridges you’ve noticed serve as what botanists call vascular bundles — essentially the plant’s equivalent of steel reinforcement bars in concrete. These structures carry both nutrients and water to the petal tips, but they also provide mechanical stiffening that prevents the dramatic curves from collapsing under their own weight or from wind stress. The fact that these ribs are thickest at the center reflects the same engineering principle you see in airplane wings, where the structural supports are heaviest where stress concentrations are highest.

The Tiger Lily’s architectural accomplishment is a marvel of natural engineering. Each part of the structure serves more than one purpose while keeping the flower’s shape intact, helping the flower resist environmental damage or trampling by pollinators. In this photo, we see an example of its structural strength: despite a petal from the flower on the right getting trapped beneath the stem of another flower, the rest of the flower retains its oval, recurved shape — which helps ensure that its splayed stamens are properly accessible to pollinators.

With this wider view, we can also develop some insights into how the Tiger Lily’s architecture supports its reproductive strategy. I included the quotation from Exploring Biology at the top of this post because, coincidentally, it uses Tiger Lilies to explain how pollinators typically help flowers reproduce (click here if you’d like to read the full explanation). Simplified, the Tiger Lily wants its pollen transferred from any of the six anthers (the thin, oval-shaped structures at the end of each stamen) — to the stigma (the orb at the end of the magenta-colored spike that is centered among the stamens). It does so by enticing the pollinators with its physical appearance as they seek the nectar the Tiger stores near the top of the stamens (generally where the stamens are shown at the bottom of the closeup photo above).

To get to the nectar through this obstacle course, pollinators flit about the flower’s various structures, and the resulting physical vibrations or physical movements (often aided by wind) get the transfer done just as the Tiger Lily wants. Consider your own observations of the movements of a hummingbird, for example, and you can see how such motion — including the bird’s wing-wind — facilitates pollination. And consider the difference between hummingbirds (one of the Tiger Lily’s largest, most highly favored pollinators) and smaller visitors, like bees or moths — who will navigate rapidly or hover throughout the flower segments, yet accomplish the same thing.

The Tiger Lily’s overall architecture supports all this in several ways. The staggered arrangement of two lilies in bloom, with one waiting to bloom, means that pollination opportunities will be presented over multiple days. Their presence on different horizontal planes induces pollinators to report for duty from multiple physical directions, so flowers are less likely to compete with each other for the attentions of individual pollinators. The stamens — whose curves reflect a simplified version of the recurved petals above them — are positioned far enough apart to let pollinators whizz by them, but close enough to each other that physical contact is likely to take place. The stamens are supported by the same architectural strength that supports the flower petals, something that is evident in that you almost never see broken stamens on Tiger Lilies (or any other lilies) until the flower’s pollination time has passed and the flower itself begins to disassemble. Finally, each flower’s horizontal axis is slightly different, which helps ensure that sunlight passes through the spaces between petals, lights up the flower’s center near its nectar repositories, reduces the chance that one flower will cast dark shadows over another, and presents varying color contrasts throughout any single day that will encourage visits by different potential pollinators.

I photographed these Tiger Lilies near the beginning of their blooming cycle, so we don’t see how the plant’s structure changes after pollination occurs. In my next posts, however, we’ll take a look at images of another lily with the same Turk’s Cap form — Lilium speciosum — that posed for me on more than one trip, showing the remarkable changes that pollination induced.

Thanks for reading and taking a look!

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From “Treasure Hunts in East Asia” in Lily (Botanical) by Marcia Reiss:

“European collectors did not open the treasure chest of lilies in East Asia fully until the nineteenth and early twentieth centuries. One of the first and most popular discoveries, the tiger lily, L. lancifolium, was sent from Canton (now Guangzhou) to Kew Gardens in London by William Kerr in 1804….

“A Turk’s cap lily, it forms tiny black bulbils in each leaf axis, making it easy to propagate. The Chinese had a charming anthropomorphic description for its downward-facing form and reflexed petals — the ‘Flower that turns its Head to See its Offspring’. But the Japanese saw it quite differently. Its Japanese name is oniyuri, the ogre lily, and while its orange colour may account for the name tiger lily, its speckled petals seem more reminiscent of a leopard, albeit one with purple spots. (There is also a panther lily, L. pardalinum, a Turk’s cap species found in California, but it also has spots.)

“A few orange-coloured lilies had made earlier appearances. L. bulbiferum, native to central Europe, is a remarkably realistic detail in the Portinari Altarpiece, of the Adoration of the Shepherds, commissioned by the Medici from the south Netherlandish painter Hugo van der Goes in 1475. It gets its name from the bulbils in its leaf axis, like those of the tiger lily….”

From “The Lily” in The Collected Earlier Poems by William Carlos Williams:

The branching head of
tiger-lilies through the window
in the air —

A humming bird
is still on whirring wings
above the flowers —

By spotted petals curling back
and tongues that hang
the air is seen —

It’s raining —
water’s caught
among the curled-back petals

Caught and held
and there’s a fly —
are blossoming

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Hello!

The mid- to late-summer floral displays at Oakland Cemetery feature various collections of lilies, amaryllis, and crinum — collections that, as a whole, rival the diversity of their seasonal predecessors (irises and daylilies) and their seasonal successors (asters and mums). Over the next several weeks, we’ll take a look at some of these species — flowers and plants whose scientific identification is often challenging, as many of them have multiple shared common names stemming from similar visual characteristics, but have botanical stories that are very different.

I decided to start this next post run with Tiger Lilies (Lilium lancifolium), because this is the first summer in three years that I managed to catch them in bloom. The bloom time of amaryllis, crinum, and many other lilies is quite predictable, but the Tiger seems to slide its blooming by several earlier or later weeks depending on weather conditions preceding the plant’s emergence from the soil. In those years I’ve gotten it to pose for photoshoots, we’ve held those shoots as early as the first week of June and as late as mid-July. This year — when I was out still photographing daylilies — I noticed the Tiger Lilies just starting to produce flower buds on June 7, so went back exactly two weeks later to find this nice grouping of flowers ready to capture.

The quotation from the book Lily (Botanical) by Marcia Reiss above serves as a useful way to kick off these lily posts. The author introduces the Tiger Lily’s official name, Lilium lancifolium — a replacement name for Lilium tigrinum, from which the Tiger Lily common name was derived. She also mentions the Japanese name “ogre lily” — which I had not heard before, though I’ve seen in my research that the Tiger Lily has also been referred to as a Leopard Lily, Devil Lily, Orange Lily, and Pine Lily, depending on the resource I’ve come across and its connection to a particular region or vernacular. While we don’t need to be too concerned about these variations, it can be fun to observe how they’re used when we humans encounter plants in different historical eras or contexts. Here we’ll stick with Lilium lancifolium and Tiger Lily as the most accurate and prevalent current usage.

Reiss describes the Tiger Lily as a “Turk’s cap lily” — a phrase that is often used to describe some specific lily cultivars, including the Tiger Lily. Most accurately, though, “Turk’s cap” is best used as a description of a lily form rather than a specific lily. “Turk’s cap” describes the way the flower petals of some lilies curve upward and meet at the center, reminiscent of the way a turban is assembled. While people — including me — often call some lily variants by the name “Turk’s Cap Lily,” we’ve learned more about the subtle distinctions in plant naming conventions so will no longer do that.

I noticed Reiss’s mention of “bulbils” because Wikipedia’s article about Lilium lancifolium describes the Tiger Lily like this:

“L. lancifolium produces aerial bulblets, known as bulbils, in the leaf axils. These bulbils are uncommon in Lilium species and they produce new plants that are clones of the original plant. The flowers are odorless. Each lasts a few days and if pollinated produce capsules with many thin seeds.”

This excerpt is only four sentences, but there’s actually a lot going on here that is fascinating to learn about once you uncover how significant it is that “bulbils are uncommon in Lilium species” and that the bulbils “produce new plants that are clones of the original plant.” This means that Tiger Lilies — along with a consequential minority of other lilies — employ dual natural reproduction strategies: reproduction aided by pollination, which, as one might expect, would produce related but genetically different plants; and the production and dispersal of bulbils, which produce exact clones of the plant that distributed them. And while you may encounter sources referring to these berry-looking globes as seeds, they’re not seeds at all. They are, in effect, mini-me versions of the original plant, whose escapades — described here — go like this:

“Two of the best-known bulbiliferous plants are Lilium bulbiferum of Europe and L. lancifolium of Asia. The latter species is common in cultivation and has naturalized in North America and Europe. Both species form bulbils in the axils of the leaves. In Lilium lanceolatum, the margins of the leaves are turned up slightly where the leaves join the stem. Raindrops landing on the leaves are channeled toward the stem and dislodge bulbils (ombrohydrochory), causing them to fall to the ground. Bulbils dispersed by raindrops land near the parent plant and might be carried farther by sheet flow or runoff. If not dislodged by rain, the bulbils eventually fall when the stem senesces at the end of the growing season.”

Since I captured these Tiger Lilies early in their blooming cycle — when most of the plants had one flower in bloom, with one waiting on the side to bloom later — their bulbil production was also in its early stages. Here’s one of the plants in a tight closeup, where you can see two bulbils positioned exactly as described above, with the leaves slightly folded and angled to catch and channel raindrops to help detach the bulbils.

The bulbil on the right demonstrates yet another feature of their production: those half-dozen black dots just below the red circle are not spots; they’re bulbils that didn’t form fully and so were pushed down the leaf in favor of one bulbil growing to maturity. This pattern illustrates how the plant allocates its energy resources: since it must divide that energy between flower and bulbil production in its two-part reproductive strategy — and respond to environmental conditions at the same time — it may produce some bulbils that don’t fully form while working on developing its spectacular flowers.

That bulbil-making plants like the Tiger Lily produced exact clones of their source plant would have been a twentieth-century discovery, requiring the scientific methods and tools to analyze plant DNA. Earlier botanists might have observed, by contrast, that the bulbils produced new plants — by a method similar to that of seed or bulb distribution — but would not have understood the natural cloning or clonal reproduction that would be proven much later. As I discussed in several of my iris project posts, these botanists often relied on evidence presented in botanical drawings and combined that with their fieldwork to theorize about plant behavior. So it’s not surprising to find drawings or watercolors of Tiger Lilies with their bulbils in the 17th, 18th, and 19th centuries — like this pair by Pierre-Joseph Redouté (from Volume 7 and Volume 8 of his book about lilies Les Liliacées [The Lilies]), where the bulbils are as prominently featured as the flower blossoms themselves:

These accurate renderings served both artistic and scientific purposes, especially in the eras of botanical exploration that preceded pervasive use of photography. Both drawings show exactly the positioning of bulbils discussed earlier: each bulbil emerges near the connection of leaves to the stems, with each leaf slightly curved and angled downward to enable the bulbils to slide from the plant to the ground, especially during a rain. Botanists working with such Tiger Lilies likely would have observed and drawn conclusions about how this natural behavior enabled Tiger Lilies to spread, with those observations and conclusions providing the basis from which later discoveries would determine that the new plants were duplicates of the originals.

In the next post, I’ll explore the visual characteristics of these flowers, and what else — besides bulbils — photographs of them can reveal, well beyond how photogenic they are to the camera and how delightful they are to see (and re-discover) in real life.

Thanks for reading and taking a look!

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