Some practical tips to identifying an often confusing plant.
Gladioli are some of the most striking flora found at Verloren Valei, but this large genus can be tricky to identify.
The genus Gladiolus belongs to the family of Irises or Iridaceae. Its name derives the Latin gladius meaning sword, in honour of its sword-like leaves.
Of the 270 species known worldwide, 163 are found in Southern Africa, most of them in the Cape floral kingdom. Some 33 species occur in Mpumalanga, with 12 represented on Verloren Valei.
Gladioli are perennial herbaceous geophytes. Geophytes, as Wikipedia will helpfully inform you, are plants with underground tubers that allow them to survive harsh conditions—such as the regular fires and icy winters characteristic of Verloren Valei.
When it comes to identifying gladioli, one of the big challenges is the presence of many watsonias on the reserve. The latter are similar to the gladioli in many respects, and are also part of the Iridaceae family.
I have put together a small table of what I consider to be the most important differentiators between the two genera.
| FEATURE | Gladioli | Watsonia |
| Leaf arrangement | Typically fan-shaped and arranged in a flat plane | Leaves often arranged in a loose spiral around the stem |
| Leaf texture | Firmer, more rigid sword-like leaves | Softer, more pliable sword-shaped leaves. |
| Inflorescence structure | Flowers borne on a single, unbranched spike with blooms opening sequentially bottom-up | Flowers often more densely packed on the spike, sometimes two-ranked |
| Flower symmetry | Zygomorphic (bilaterally symmetrical) with a pronounced hooded upper tepal (petal and sepal combined) | More open-faced flowers, less hooded, often actinomorphic tendencies. (Radial symmetry) Bugle or trumpet shaped |
| Style branches (the style is the stalk-like part of a flower’s pistil that connects the stigma to the ovary) | Typically 3 style branches | Typically 6 style branches (see pic below) |
| Corm characteristics | Corms with fibrous, papery outer layers (that is, a tunicated bulb or a bulb with a tunic protecting it) | Depressed corms stacked on older corms, often forming a columnar structure |
| Landing pad structure or nectar guides | Prominent lower tepals often form a “landing pad” for pollinators, especially bees and sunbirds | Lacks a defined landing pad; flowers are more tubular and upright |
On the left, the three style branches of the typical gladiolus are visible. The dark patches serve as landing pads for pollinators, indicating pollen or nectar. On the right, we see the six style branches of the typical watsonia (Photographs: Steve Vincent).
* * *
Useful botanical terms
To talk about flowers, and identify them, it’s necessary to have a working knowledge of common botanical terms. The following ones are especially useful when it comes to identifying gladioli correctly:
Tepals: When the petals and sepals are joined together, they are called tepals.
Sepals: Sepals are the leaflike, usually green parts that protect the flower when it’s in bud, and often support the petals when the flower is opened.
Perianth tube: The lower part of the tepals, where they join together to form a tube.
Style, style branches and stigma: These are all parts of the plants female reproductive organs. The style is a narrow extension of the ovary, connecting the ovary to the stigma.
Filament and anther: Along with the stamen, they form part of the plant’s male reproductive organs.
Nectar guide: Typically, these are dark markings on the tepals, showing the pollinator where to land
Bracts: Leaf-like structures within which the flower forms and opens. Gladioli have outer bracts and inner bracts. Bracts are not part of the flower itself, as the sepals are.
Cataphyll: Modified leaves at the base of the plant. They do not photosynthesise, but rather act as protection or storage.
Corm tunic: The covering of a corm. The tunic may be leathery, fibrous or papery.
Corm: An underground storage organ, vital in vegetative reproduction.
* * *
Gladiolus taxonomy
In Gladiolus in Southern Africa (1998), John Manning and Peter Goldblatt divided the genus into seven sections, based on their morphological characteristics. This gives a very useful taxonomic structure to the genus.
In this article, I will summarise only those gladioli that occur in the summer rainfall areas and that have been found in Verloren Valei Nature Reserve (VVNR):
Densiflora: This group contains 20 species of gladiolus, all found in eastern half of the country, that is the summer rainfall areas. They are normally medium to large plants, with sword-shaped leaves. Seven Species occur in VVNR: Gladiolus paludosus, G.papilio, G.crassifollius, G.ferrungineus, G.appendiculatus . G.calcuratus and G.varius.(there is some investigation required regarding the last species).
Ophiolyza: Fifteen species are listed in this group, again mainly located in the summer rainfall area. They are also medium to large plants, having long bracts and lanceolate leaves, arranged fan like in alternately and opposing rows. Only two species have been found in VVNR: G.dalenii and G. ecklonii.
Linearifolii: Seventeen species are listed in this group. All are small to medium sized plants. The stems are usually hairy and flower aseasonaly. Only one species is found in VVNR, G. woodie, with another found within 5km of the reserve, G. malvinus. It would be great to find a G. malvinus on the reserve.
Hebea: Thirty-three species are listed in this group. Although they are widespread across South Africa, most are found in the winter rainfall areas, with only one species, G. permeabilis subsp. edulis being recorded in VVNR. These plants have short soft bracts.
Homoglossum: Fifty-one species are listed in this group, predominantly in the Western Cape. Many of these species have delineated tepal patterning of dots and elongated lower tepals giving them a unique flower form and shape. One species, Gladiolus longicollis subsp. platyptalus, is recorded in VVNR.
Download a detailed guide to the gladioli of Verloren Valei, including photographs.
