A close-up view of two lilies, Lilium candidum and Lilium hybridum.

The ‘White’ Lily Lilium candidum

The large white flowers of this spectacular plant fill an interior space with an extremely pleasant fragrance. In Ontario, the plants are available as cut-flowers all year long, and help to brighten the monotony of the long, cold, Canadian winter. (As you might guess, winter is my least favourite season!)

This member of the lily family (Liliaceae) possesses flowers with six petals, three in an inner ring and three in an outer ring. The reproductive structures are spectacularly colourful, and add much to the plant’s visual appeal. Many sources however, suggest that the bright yellow anthers be removed when the plant’s stem is placed in a container, as they may stain the surfaces onto which they fall. As can be seen in the following images, the leaves are dark green and lance-shaped (lanceolate).

Although the front of each petal has some yellow colouration, the back is totally white (more correctly – cream). There is a rod-shaped prominent vein that runs the length of the petal.

The points of attachment of leaf to stem (left), and flower to stem (right), are shown below.

Notice the section of leaf in the upper portion of the image below left. Under the microscope, the upper surface is composed of cells containing chlorophyll (in chloroplasts).

The lower surface of the leaf is spotted with openings (stoma) through which gas enters the internal structure. Crescent-shaped guard cells control the size of the opening, and therefore the amount of gas transfer. These two structures form what is called the stomatal complex.

If a white portion of the surface of a petal is examined under the microscope, its cellular structure becomes visible.

The innermost section of each petal has many long irregular yellow projections that dot the surface.

Photomicrographs reveal the structure of these protuberances. Note the surface texture visible on the pollen grain in the higher magnification image.

Towards the tip of the petal, and along the petal’s edge, these projections are shorter and more compact.

Photomicrographs show interesting detail in the uppermost cells of one of these stubby protuberances.

The transformation of a bud as it reshapes to form a mature flower is shown in the two images that follow.

An unopened bud possesses a distinctly sculptural quality that is quite appealing. Note the wavy edges that develop at the tip of each petal as the bud begins to open (right image).

As mentioned earlier, the reproductive structures of the lily are colourful and large to match the flower’s size. There are six orange-yellow anthers (male pollen producing organs) each supported by a thin green filament. At the centre of the ring of stamens is the single green style supporting an almost black stigma (female pollen accepting organ).

When the flower first opens, the anthers are parallel to their filaments. In fact, the top of the filament fits into a groove in the bottom surface of the anther. (This can be seen clearly in the right hand image.)

After four or five hours, the filament slips out of the anther’s groove, and the anther moves under the influence of gravity. Since the point of attachment of anther to filament is an extremely thin strip of tissue, the anther wobbles and moves into a position roughly at right angles to the filament. This exposes a maximum surface area to any passing insect, and promotes pollen transfer.

Note in the image at left below, that a couple of anthers are still fixed in their parallel position. The image on the right shows their normal position.

The surface of the anther is deeply grooved, and coated with pollen.

Under the microscope, a pollen grain is seen to be ellipsoidal in shape. Notice the interesting surface pattern.

In the ‘White’ lily, the pistil is longer than the stamens. The style holding the almost black appearing stigma is much sturdier than the filaments surrounding it.

The two high magnification macro-photographs below show a side and top view of the stigma’s surface. The top view reveals that the stigma has three thin lobes, with pock-marked surfaces. The crevices between the lobes, and the surfaces of the lobes are covered by a clear viscous liquid which is extremely sticky. During the photographic process, a microscopic filament became stuck to the stigma’s surface and several minutes were required to pull it away from the surface with the aid of tweezers. It is obvious that this adaptation facilitates the retrieval of pollen from visiting insects that come in contact with the stigma.

Although the surface cells of the stigma appear black to the naked eye, when the upper layer is removed with a knife, and examined by transmitted light under the microscope, the cells are red. The higher magnification photomicrographs show pollen grains that have become trapped on the surface.

Located at the base of the pistil, the ovary (seed producing organ) has a columnar shape composed of six fused tubular structures.

The ‘White” Lily, sometimes referred to as the ’Madonna’ Lily is not brilliantly coloured, but it has an undeniable beauty. It is thought to have been in cultivation since the Minoan Period (~1500 BC).

The ‘Star Gazer’ Hybrid Lily Lilium hybridum (Star Gazer)

In contrast to the previous lily, this one has spectacularly colourful petals with a pinkish-white background and bright red foreground.

Shortly after opening, the petals still form an open cone around the reproductive structures. In the mature flower seen at right, the petals have bent into a perpendicular orientation, with the tips curled back towards the stem.

The surface colouration of a petal is composed of red spots and diffuse red areas. (The anthers of this old bloom have long since fallen from the tips of the filaments.)

All six orange-brown anthers are grooved, and coated with huge amounts of pollen.

Higher magnification images of anther and stigma can be seen below. Unlike the ‘White’ lily, this hybrid's stigma is light green with a red fringe.

The two lily cut-flowers discussed in this article stand out in my mind for a number of reasons. The predominant one is that they have the record for the intensity of fragrance. No other flowers that I have photographed have filled the room with such a massively pleasant odour. Beauty and fragrance together – who could ask for more?

Photographic Equipment

The ‘White’ Lily 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 ‘Star Gazer’ Lily photographs were taken with an eight megapixel Sony CyberShot DSC-F 828 equipped with achromatic close-up lenses (Canon 250D, Nikon 5T, 6T, Sony VCL-M3358, and shorter focal length achromat) used singly or in combination. The lenses screw into the 58 mm filter threads of the camera lens. (These produce a magnification of from 0.5X to 10X for a 4x6 inch image.) Still higher magnifications were obtained by using a macro coupler (which has two male threads) to attach a reversed 50 mm focal length f 1.4 Olympus SLR lens to the F 828. (The magnification here is about 14X for a 4x6 inch image.)

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

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© Microscopy UK or their contributors.

Microscopy UK Front Page
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