A Close-up View of a Flowering Begonia (2024)

For the botanical layman, Begonia plantsare relatively easy to identify. Their fleshy jointed stems,showy flowers, and distinctive asymmetric leaves set them apart fromother genera. Unfortunately, an unusual characteristic ofBegonias is that species throughout the genus can be hybridized withone another, even if they originated on different continents.This might seem like a good thing, but it has resulted in a huge numberof cultivars to be developed worldwide. Distinguishing betweenthese hybrids is a formidable task, and so for the purposes of thisarticle, I will simply consider my plant as a ‘typical Begonia’.Both its common, and genus names were suggested by Charles Plumier, aFrench patron of botanical research. Begonia and Begonia honour Michel Begon, aformer governor of the French colony of Haiti.

In fact, the subject of thisarticle was in rather ragged condition when I spotted it in the‘marked-down’ area of the greenhouse. Since it was the onlyBegonia in bloom at the time, I decided to take a chance and bring ithome, in the hope that it would survive until I finished photographingit.

The first image in the articleshows the plant’s deep green leaves, and multiple flower-heads.Below are two images showing Begonia flowers - flowers that aredistinctly different in shape than those of most other plants.

Begonias are monoecious, meaning that they haveseparate male and female flowers on the same plant. Male flowersare referred to as staminate,while female ones are called pistillate.Allof the flowers shown in the two images below are pistillate, asrevealed by their three bi-lobed stigmas. It appears as thougheach flower possesses two petals, but in this genus sepals and petalsare indistinguishable, and so both are referred to as tepals.

One of the stems supporting a groupof flowers can be seen in the two images that follow. The manypale green tri-lobed structures are the ovaries of pistillateflowers. Note at the very top of the stem, several oval leafletswhich have no connecting stalk. Such leaflets are referred to as ‘clasping’.

These clasping leaflets occur onlyin the top-most section of each of the plants stems.

Closer views of a leaflet revealits serrated edge, and several reddish, irregular longitudinal stripes.

The Begonia studied here appears togrow from a unique root structure that looks like a large tuber calleda caudex. The plant’sstems grow from this caudex, which is half beneath the soil, and halfabove. The visible portions of several of these root structurescan be seen below. Multiple stems originate from eachcaudex. Notice the strange ribbon-like hairs that grow profuselyfrom the bases of stems.

Several additional ground levelviews of the plant can be seen below. Notice in the first imagethat the green surface of the caudex is covered with irregular brownscales that are loosely attached. During hard times, the plantcan lose all of its foliage until nothing remains but the caudex.When conditions improve, the plant is able to regrow stems, leaves, andflowers.

Three views of stems follow thatshow their pale yellowish-green colouration, and tiny bright redspots. The length of the stem’s irregular, ribbon-like hairsdecreases as one moves up the stem. Similar rough-looking hairsappear to grow from both upper and lower leaf surfaces.

Closer views of the surface of alower stem reveal the structure of these strange hairs. Many arequite long, and have apparently dried out to become thread-like neartheir tips. It’s interesting to note that all of the hairsoriginate from the bright red, irregularly shaped spots on the stem’ssurface.

Upper stems appear to be dividedinto bamboo-like sections by raised rings. Notice how the stem’scolouration, number and intensity of spots, and hair lengthchanges above the ring shown in the second image.

Here are a couple of images showingbud-stage Begonia flowers. In each bud the two tepals are closedlike the two sections of a clam. If you examine the images verycarefully, you may be able see that some buds are attached to a greenbase, while others are not. I wonder what this means?

The answer of course, is that someof the buds are pistillate, and some are staminate. The two seenat the bottom of the image on the left below are pistillate, asevidenced by their light green ovaries. The bud at the top of theimage (which is seen close-up in the right hand photograph), isstaminate.

Still closer views of this male budcan be seen below. Notice that both its tepals, and its stalk arecovered with bulbous-tipped glandular hairs. Most hairs emanatefrom the red spots on a surface.

As you can see below, the stalks ofboth male and female buds may grow from the same junction on the stem.

Additional views of glandular hairsfollow. Note in the left image, the two tiny leaflets that jointhe stalk just beneath a bud.

Two images can be seen below thatreveal pistillate buds in the process of blooming.

When fully open, the two tepalsthat form the flower’s combined calyx-corolla are positioned almost ina plane.

Let’s now take a closer look at themale staminate flowers of the Begonia. In terms of the flower’stepals, they are identical to pistillate ones. However in thiscase there is a cluster of stamens at the flower’s centre. Inthis particular species, the stamens are grouped in an asymmetric, (orzygomorphic) mass that resembles a bunch of bananas.

Higher magnification shows thateach bright yellow anther is supported by a short, pale yellow-greenfilament.

A view from above the group ofstamens shows how tightly they are packed side by side in the cluster.

Front and side views of a clusterreveal that all stamens have a similar curvature.

Now let’s look more closely atpistillate flowers. Here there are three bright yellow stigmas,each with two lobes at its tip.

Much higher magnification revealsthat the surface of each bi-lobed stigma is entirely covered by finehairs that increase its surface area, and thus help to acquire, andretain pollen grains. Notice also that the styles supportingstigmas are stocky and curved.

A side view of a female flowershows clearly that the three pistils are connected to an impressivelylarge, light green ovary which possesses three thin, but broad, lightercoloured ‘wings’. (The third wing is not visible in thephotograph.)

Begonias are noted for theirasymmetric leaves. The upper surface of one such leaf which has8, pointed, serrated lobes is shown below. The image on the rightshows the strange bright red ‘beard’ composed of coarse hairs thatgrows from the point of connection of the stalk to the leaf.

A view from beneath the same leafshows that its underside has a bright red colouration! The imageon the right shows a different view of the ‘beard’ mentioned above.

More highly magnified views of theunderside of a leaf can be seen below. Notice the many hairs thatgrow from the leaf’s surface, and edge. Begonia leaves containthe chemical calcium oxalate within their cells, which makes thempoisonous to animals.

The approximately 1500 species ofwild Begonias grow in a wide variety of ecological niches, most intropical and sub-tropical regions. Only one tropical region iswithout native species, and that is Australia!

The low magnification, (to 1:1),macro-photographs were taken using a 13 megapixel Canon 5D full frameDSLR, 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 macrolens, the MP-E 65 mm 1:2.8, was used to take the remainder of theimages.

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

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