A close-up view of two members of the Hyacinthaceae family

Shortly before Valentine’s Day, stores and garden centres in my area are flooded with spring blooms. Crocus, hyacinth, narcissus and tulip plants seem to be everywhere. Perhaps this is a good thing, since the climate of southern Ontario, where I live, will not support such living things, out of doors, for at least another three months. The sight of these attractive flowers, gives a welcome preview of the coming spring!

Most of the hyacinths available today have been cultivated over many years to improve the size, colour, and shape of the flowers. Originally based upon Hyacinthus orientalis, native to the Mediterranean region, the many cultivars available today are remarkable in their diverse colourations. Even as far back as the 1700’s, two thousand different hyacinths were said to be in cultivation in Holland (the major commercial supplier).

I suspect that most of us have had a powerfully scented hyacinth plant at one time or other in our homes. Do we really look closely at the buds, and flower-heads I wonder? I think not! The goal of this article is to provide a detailed look at the structure of three different hyacinth plants, not so much from the standpoint of biology, but to highlight the sculptural beauty of their forms.

White Hyacinth

Here is a pot containing three bulbs. Notice the very pale green groups of buds emerging from the leaves that surround them. This light colouration is an indication that the flowers will be white. Some groups of buds are stubby and broad, while others are long and thin.

At a slightly earlier stage, one of the stubby bud groups is still enclosed by the overlapping leaves.

The occasional stem is much greater in diameter than the others. Note that buds near the tip are tightly packed, while those lower on the stem tend to be solitary.

The two images that follow show one of the long, thin bud groups. Notice the small leaflet that sometimes grows up from the base of a bud.

There is an attractive sculptural quality which is evident when examining individual hyacinth buds. At this stage it is difficult to imagine that the green ‘sections’ will eventually transform into the totally white petals of the mature flower.

Each bud has a single curved green ‘leaflet’ growing out from beneath the bud’s stalk. Strangely, the size of this leaflet doesn’t seem to be related to the maturity of the bud.

Proof of this can be seen in the image below. Notice the very small size of the leaflets beneath the open flowers.

In the hyacinth flower-head, flowers bloom from bottom to top.

The same flower-head, a day later, has more flowers open.

Although hyacinth plants have straight stems to begin with, as the flower-heads begin to bloom, the combined mass of stem and flowers is great enough to cause the bloom to start a slow but inevitable descent to the table top.

If you look closely at this early stage, the flower resembles a starfish, and the tips of its six petals are still green.

The petals’ green tips can be seen in the closer images that follow. The image on the right also shows the boat-shaped nature of each petal’s tip (top right corner).

Hyacinth leaves are thick, and very fleshy. A more highly magnified view reveals the many parallel grooves, and the multitude of microscopic spots on the surface.

Eventually, all traces of the original green tint disappear from the flowers’ petals.

With time, each petal curves back towards the stem. At the flower’s centre, the bright yellow anthers (male pollen producing organs) can be seen. The stigma (pollen accepting organ) is so short, that it is normally hidden by the anthers. Note the genetic defect in the flower shown in the right-hand image. There are two ‘extra’ petals, one of normal size, and one dwarf petal with an unusual curvature.

The extreme close-up of the centre of a hyacinth flower shows the group of wrinkled yellow anthers. The stigma is completely obscured by the overhanging stamens.

Under the microscope, the single pistil, composed of the stigma, and supporting style with the same diameter, can be seen to have several pollen grains clinging to its surface.

The three images that follow show one of the anthers with its coating of pollen grains. The first image also shows the very short filament at the anther’s base. The third image shows the rather irregular shape of hyacinth pollen grains.

When a petal is pulled away from a flower, a thin layer of white tissue often bridges the gap. The irregular cellular structure of this tissue can be seen in the photomicrograph below.

The filament that supports an anther is attached to the base of the petal. As the filament is pulled from the petal’s base, the tissue exudes a clear, very sticky fluid. The image at right shows a thick filament of this fluid clinging to the two surfaces.

Purple Hyacinth

Although the general structure of this cultivar is identical to the previous variety, the light purple petals, and sky-blue base, make the flowers visually different.

The stem in this variety has a speckled purple colouration that results in a darker appearance.

The white hyacinth has buds with a completely green surface, while purple hyacinth buds have a mottled bi-coloured appearance.

A close-up of a single bud shows the mottled colouration more clearly. Notice that even at this early stage, the bud has a striking blue base.

While comparing the buds in the two images that follow, notice how the purple colouration deepens as the bud matures.

As the petals of a flower begin to open, some still have the remnants of the earlier greenish colour (right image).

A short time later, the petals have opened wider still, and the flowers have a random, unsymmetrical appearance.

The short flower stalks are cupped at the base by very tiny green ‘leaflets’. This is one feature that is different than the white variety, which has much larger and longer ‘leaflets’.

Eventually, the flower’s petals open enough to reveal the reproductive structures. Notice that although the anthers are deep purple (almost black), the pollen that coats them is yellow. If you look carefully at the image on the right, you may be able to discern the top of the pale yellow stigma at the centre of the ring of anthers.

Grape Hyacinth

The genus name of the grape hyacinth, Muscari, comes from the Greek word for musk, and refers to the powerful scent given off by the flowers. This particular species has clusters of blue, bell-shaped flowers at the tips of stems. Other varieties have larger more densely packed flowers that give the appearance of inverted bunches of grapes.

The plant’s buds are tightly packed in an arrow-head shaped group at the stem’s tip.

As is the case with most flowering spikes, the flowers of grape hyacinth bloom from bottom to top. Notice that the fringe of lobes at the open end of the flower has a white colour.

The top surface of each bud has a symmetrical pattern formed by the six lobes of the yet unopened corolla (ball-shaped base of the flower).

Notice that the blue colouration of the flower is deepest in the centre of each of the fused petals that form the corolla. Also note the dark coloured anthers that can be seen in the open ends of the flowers.

In order to take photomicrographs of the reproductive structures of a flower, it is necessary to peel away the tissue of the corolla. The pale blue colour of the tissue can be seen in the low magnification image that follows.

Two higher magnification photomicrographs of the sticky inner surface of the corolla show the many ellipsoidal pollen grains that adhere to the surface.

The corolla’s inner surface is, as mentioned earlier, completely coated with a clear viscous liquid, several droplets of which can be seen below.

Occasionally, when studying the pollen of a flower, one comes upon rogue pollen grains that don’t belong. The interestingly shaped grain below must have been acquired at the nursery or garden-centre.

The two images that follow show flower-heads at different stages of blooming. Notice that the flower stalks decrease in length towards the top of the flower-head.

If you look into the end of one of the flowers, the ring of anthers is visible. In the right-hand image the tip of the pale yellow stigma can be seen, (out of focus), just to the right of centre.

Under the microscope the entire pistil can be seen in the left image. The pale yellow-green pollen covered stigma is supported by a stocky, green-ribbed style. The cellular structure of the style can be seen in the image on the right.

At the right side of the left image below, this same pistil is visible. To its left, several of an immature flower’s anthers are also visible. The image on the right shows the bi-lobed nature of the anther more clearly. (Note that one lobe has matured to a dark red-brown colour, while the other is still green.)

A mature anther, and supporting filament, (from below), can be seen in the image that follows.

I hope that the images in this article have given you a deeper appreciation of the beauty of the hyacinth, not only at the normal visual distance, but also when viewed at macroscopic and microscopic levels.

Photographic Equipment

The macro-photographs were taken with an eight megapixel Canon 20D DSLR equipped with a Canon EF 100 mm f 2.8 Macro lens which focuses to 1:1. A Canon 250D achromatic close-up lens was used to obtain higher magnifications in several images.

The photomicrographs were taken with a Leitz SM-Pol microscope (using a dark ground condenser), and the Coolpix 4500.

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© Microscopy UK or their contributors.

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