A Close-up View of the

"Peruvian Lily"

(Alstroemeria psittacina)

by Brian Johnston   (Canada)

The Alstroemeria plants (lily family - Liliaceae) photographed in this article are more commonly known as the Peruvian Lily, or Lily of the Incas.  They are native to South America, growing mainly in the cool mountainous regions of the Andes.  About thirty species of Alstroemeria occur in the grasslands and pampas.  The species psittacina (translation - “resembling a parrot”) is native to northern Brazil.   Horticulturalists have worked with the species for many years to produce the many hybrids and cultivars available today.  During the long, cold Canadian winter, the colourful blooms are available from florists as cut-flowers which last up to three weeks!

The first image in the article shows a typical flower with three petals and three sepals.  The sepals are brightly coloured, and not solid green as in many other flowers.  The petals can be distinguished by the sharp point that grows from the rounded top.  Sepals possess a greenish band in this particular cultivar.

A second cultivar with purple-white coloration is shown below.

The base of the flower has a swelling that contains the ovary (seed producing organ).  Notice the purple ridges on the ovary’s surface.  These ridges continue down the flower’s stalk (right image) and spiral slightly in an unusual fashion.  (The flower’s petals and sepals have been removed.)

Notice in the image at left, the two purple-spotted upper petals.  Behind them is a sepal which is twice the width of a petal.  From behind, this sepal effectively covers the two petals (right image).

An early stage bud, and a more mature one can be seen in the images below. 

Some buds have deeper coloration than others.

The edges of both petals and sepals are slightly saw-toothed in this cultivar.

Reproductive structures are prominently displayed at the flower’s centre.  (More about these later.)

An outer sepal (left image), and inner petal (right image) are shown below.

If one of the petal’s red “spots” is examined under the microscope, its cellular structure becomes visible.

The Peruvian lily possesses 6 stamens, each consisting of an anther (male pollen producing organ) and a supporting filament.  A protective cap-like structure or cover, called the tegmen encloses some, but not all of the anthers when the flower first opens.  These four-sided light green grooved structures are an adaptation to prevent self-pollination.  Eventually the anther-caps fall off, revealing the darker coloured pollen encrusted anthers.

A photomicrograph showing the cellular structure of one of these anther-caps can be seen below.

With higher magnification, the cellular structure appears similar to the underside of a leaf, with epidermal tissue containing clearly defined stomata and guard-cells.  (These allow and regulate the entry of gas into the structure.)

The anther-cap usually opens by splitting along one of the narrower sides.  This split, and the many attached pollen grains can be seen in the following photomicrographs.

A pollen grain that has adhered to the surface of a filament is shown below.  The grain’s surface is not smooth.

The following tiny crop from a much larger photograph - (which accounts for the poor image quality) -  shows the moment of separation of two anther-caps from their anthers.  Note that at this early stage, the anthers are a yellow colour.

Anthers, when exposed, begin to darken and eventually become almost black.

Reflected light (left), and transmitted light (right) photomicrographs of the surface of an anther reveal irregularities in the shape of pollen grains.

Higher magnification phase-contrast images show that a grain has a concave ellipsoidal shape.

The occasional grain has part of its surface missing.

The Peruvian lily flower has a single pistil composed of a style which supports the stigma (female pollen accepting organ).  At its tip, the stigma branches into three lobes which are parallel to one another, and therefore difficult to distinguish with the naked eye.  The image that follows shows the many protuberances on one lobe’s surface.  These projections help catch and hold pollen grains that have been transported to the flower by insects.

Higher magnification reveals the shape of the protuberances.  The two stigma lobes shown are from different cultivars and this accounts for the difference in colour.

The macro-photograph below shows a stem node - the point at which the leaves are attached.  Note that in this species the leaves do not have stalks.

Alstroemeria leaves have a broad lanceolate shape.  The image shows the upper surface of a leaf.

Photomicrographs of the upper surface reveal white fluid transporting channels, and in the case of the right image, green chloroplasts within the cells.

The lower surface of a leaf has many prominent veins.

Under the microscope it can be seen that the guard cells have closed, preventing gas from entering the interior of the leaf.

Here is a second Alstroemeria cultivar with a more colourful appearance.  The photomicrograph at right shows the cellular structure of a spot at the base of one of the top petals.

The distinctively shaped ovary is similar to the one seen earlier.

The short columnar structure between the two capped anthers is the flower’s pistil.  Notice that two of the anthers have fallen from the tips of their filaments.  (This occurs frequently.)

Inspection reveals that both anther-caps and anthers have a flattened oval shape.  In the image at right, the sepals and petals have been removed to show the reproductive structures more clearly.  The pistil is to the left of the right-hand stamen.

Two additional views of uncapped and capped anthers follow.

The most colourful of the three cultivars studied is shown below.  Note the trumpet shape of the flower when viewed from the side.

It is not surprising that the reproductive structures are identical to those seen earlier.

The depth of field in high magnification macro-photography is extremely small.  This makes focusing a real challenge!  In the left image, the anther-cap is in focus, while in the right image it is the surface of one of the anthers that is in focus.

Most readers of this article have probably had an Alstroemeria bloom as part of a cut-flower arrangement at some time or other.  I hope that the images included here have given you a more in-depth look at this popular flower.

Photographic Equipment

Most of the 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 few 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 a dark ground condenser), and the Coolpix 4500.

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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