A Close-up View of the

'Seiryu' Formosan Blue


Tricyrtis formosana 'Seiryu'

by Brian Johnston   (Canada)

Tricyrtis formosana ‘Seiryu’ is renowned for the blue colouration of the tips of its sepals and petals.  (References refer to these as tepals since “they” say that the flower’s sepals and petals are indistinguishable.  In reality, this is simply not the case, and so in this article, I will refer to them as separate entities.)  The cultivar name ‘Seiryu’ refers to the Japanese name of one of the four gods of the Celestial directions.

As is true of most Toad-Lily plants, this one blooms during the fall, and if the weather permits, may actually continue blooming until November!  Although considered low-growing and semi-creeping, the example photographed for this article had some upright stems to about twenty-five centimetres in height.

Of the three Toad-Lily cultivars that I have studied, only one, Japanese Toad-Lily (Tricyrtis hirta ‘Miyazaki’ ) produced seed-pods.  In both of the other plants, when the flowers completed booming, they simply shriveled up and dropped off.  For this reason most Toad-Lilies are propagated by root cuttings, stem cuttings, or by division.

In the bud stage, the flower’s three sepals protect the interior petals and reproductive organs.  At the base of each sepal is a light-green, bi-lobed spur that acts as a nectary in the blooming flower.  Notice the hairiness of both the bud’s stalk, and the outer surface of its sepals.

Blue Toad-Lily flowers are small, (~ 25 mm), but spectacular nevertheless.  They are star-shaped, with an outer whorl of three oval sepals, and an inner whorl of three narrow petals.  Three bright red styles extend out, umbrella-like, above the petals.

A side view shows the red-spotted column at the flower’s centre formed by the flowers six filaments.  These filaments curve outwards, and a light-brown anther hangs from each.

The flowers of Tricyrtis formosana ‘Seiryu’ are simply spectacular.  The range of hues displayed is extraordinary, from blue through mauve to white, red and beige.  Compared with many other Toad-Lily cultivars, this one seems to display fewer spots, and thus the viewer concentrates on the overall colour scheme rather than being distracted by the spottiness.

Notice in the two views shown below, the dramatic difference in the shape of the wide sepals, and narrow petals.  Even at maturity, these sepals and petals don’t open out much more than the ones shown in the image. 

The three bi-lobed nectaries mentioned earlier can be seen at the base of the sepals in the image below.  Note that the outer surfaces of petals and sepals have no spots.

The images that follow show the flower’s reproductive structures.  Six light brown anthers that face down towards the flower’s centre are held aloft by the curving ends of purple spotted filaments.  Above these male organs, are the brilliantly coloured, forked ends of the three styles.  If you look carefully, you can see the small white patch at the tip of each fork – the stigma.  Like most other Toad-Lilies, this one has tiny glandular protrusions along the edges of its styles.

Each anther is connected to its supporting filament by an extremely narrow thread of tissue.  A crevice divides the anther into two lobes.  Notice in particular, that the upper surface of the anther is smooth at this point.

If you examine the two images below carefully, you can see that a change has taken place.  Time has past, and the upper surfaces of the anthers now look ragged and rather rough.

The side views that follow show this same phenomenon.  If the six, red-spotted filaments were removed, what would we see?

The answer is shown below.  At the base of the three styles is the light green, three-chambered ovary.

Careful examination of the flower’s anthers reveals that they are producing pollen grains on their edges, and on their lower surfaces (not visible from above).

The upper surfaces of some of the anthers have curled, revealing the pollen covered surface beneath.

The flower’s three glandular-edged, and stigma-tipped styles are visible below.

Higher magnification reveals more details.  The stigma pad on each style fork generally faces down towards the flowers sepals and petals.  A spherical, membrane covered liquid droplet is exuded from each tubular stalk to form a glandular protrusion.

As one moves towards the reproductive structures, it finally becomes possible to resolve the graininess of individual pollen grains.

Much higher magnification shows the tiny, thread-like connection between a filament and the anther that it supports.

During the early stages of growth, an anther produces pollen, but the grains are contained within the two semi-circular chambers that can be seen on the right in the image below.  Eventually, each chamber “unzips” along its length to reveal the pollen within.  Botanists say that the anthers dehisce at this point, and release their pollen.  This is the process shown at right in the image.  Eventually both lobes completely “unzip”, and the anther looks like the one at left.

For comparison, here is a much closer view of each stage.

How blue a Tricyrtis formosana ‘Seiryu’ sepal or petal appears depends upon the colour temperature of the illuminating light, and the angle of view.  Daylight seems to exaggerate the blueness.  The image on the right shows a sepal, and the tuft of short hairs that project from its tip.

Ketzel Levine, (Talking Plants on National Public Radio), describes Toad-Lily flowers as "surrealistic fantasies which stand on three rubber boots."  Despite their small size, they certainly produce a stunning visual impact when viewed close-up!

Photographic Equipment

The low magnification, (to 1:1), macro-photographs were taken using a 13 megapixel Canon 5D full frame DSLR, using a Canon EF 180 mm 1:3.5 L Macro lens.

A 10 megapixel Canon 40D DSLR, equipped with a specialized high magnification (1x to 5x) Canon macro lens, the MP-E 65 mm 1:2.8, was used to take the remainder of the images.

Further Information


A Flower Garden of Macroscopic Delights

A complete graphical index of all of my flower articles can be found here.

The Colourful World of Chemical Crystals

A complete graphical index of all of my crystal articles can be found here.

 All comments to the author Brian Johnston are welcomed.

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