A Close-up View of the Hybrid

Passion Flower

'Imperatrice Eugenie'

Passiflora x belotii

(P. alata x P. caerulea)

by Brian Johnston   (Canada)

When you take a flower in your hand and really look at it,
it's your world for the moment. I want to give that world to
someone else. Most people in the city rush around so,
they have no time to look at a flower. I want them to see
it whether they want to or not.

- Georgia O'Keeffe (Artist)

In an earlier Micscape article, I investigated two members of the Passifloraceae family – Passiflora caerulea, and Passiflora coccinea x incarnata.  In this article, I will describe the extremely beautiful hybrid Passiflora x belotti, which was produced by crossing P. alata with P. caerulea.  Unlike the other two species, this one has an absolutely wonderful scent.

In 1824, Dr. Lindley named this hybrid Passiflora alato-caerulea,  and over the years it has been given other names:  Passiflora munroi, Passiflora pfortii, Passiflora x belotii, etc.  Today, one of the commonest names is Passion Flower ‘Imperatrice Eugenie’.  The dedication is to the wife of Emperor Napoleon III.

All Passion Flower blooms are strikingly complex, and seem almost alien when compared with simpler flowers.  Sepals, petals, coronal filaments, and reproductive structures all combine to form an amazing botanical spectacle.

As usual, my purpose is to show that the beauty of a flower, when viewed from a distance, is only part of the picture.  When viewed close up – very close up, the structures that combine to form the flower have a beauty all of their own!  (Note: As the camera moves closer to a large flower, it becomes more and more difficult to keep everything in the picture in focus.  Photographers refer to this as a ‘depth of field’ problem, and it requires a particular part of the flower to be chosen to be ‘in focus’.  In the image on the left below, I have chosen the purple coronal filaments to be in focus, while in the image on the right, I have chosen the more distant reproductive structures to appear in focus.)  If you look at the image on the right, you will notice that the flower’s reproductive structures (stigmas, ovary, and anthers) are held by a sturdy green, rod-like structure which is called the androgynophore.

As the camera moves closer to a flower, this depth of field problem becomes more severe.

A mature Passion Flower bloom can be seen below.  What however, did the bud stage look like?

The answer can be seen in the image that follows.  Keep in mind that the Passion Flower plant is a vine that holds itself aloft by having its tendrils curl around nearby plants, or other inanimate structures.  One such tendril can be seen in the image.  Notice in particular, the strange, tiny bulbous structure growing from the leaf stalk, just to the right of centre in the image.  This is a nectariferous gland.

Much closer views of a nectariferous gland can be seen below.  These glands produce a sweet, viscous liquid called nectar that attracts insects.  In some species, the nectar attracts insects to help fertilize the flower, and other species, it attracts insects that devour a particular predator that might eat the plant’s tissues, or suck the juices from them. 

Three additional images that show these glands can be seen below.  If no insect partakes of the liquid refreshment supplied by the glands, the droplets become so large that surface tension can no longer hold them in position, and they fall onto whatever is immediately beneath.

Let’s return to the bud-stage of the blooming process.  The bud is protected by three modified leaflets.  Within this protective envelope, there are five sepals (modified leaves) which in turn protect the flower’s petals.  Each sepal is tipped by a slender spike.

These modified leaflets and sepals can be seen more clearly in another bud.

Notice the interesting structural engineering involved at the point of connection of a bud stalk to the main vine.  The two stalks which angle directly left are connected to leaves.

Tendrils that have not come into contact with something to hold on to, seem to form neat, regular coils.

However, when a tendril does find a ‘foot-hold’, it certainly seems to make certain that it won’t be dislodged!

Over a period of many days, each bud grows in overall size, with its length increasing faster than its diameter.  Notice that the length of the sepal spikes has not kept up with the overall growth.

Eventually,  the sepals begin to separate as the time of blooming approaches.  This reveals the pale pink colouration of the flower’s petals beneath.

This stage can be seen more clearly in the images that follow.  Both the sepals and petals of the Passion Flower are thick and fleshy.  If you look carefully, you can see that the sepals have begun to lose their green colouration along the edges. Interestingly, the inner surface of each sepal is white.