One often comes across the name of the species as Bulbine mesembryanthemoides, but because Haworth used the spelling mesembryanthoides in his original description, this has to be accepted as correct.
Subspecies mesembryanthoides has a small underground tuber and usually 1-2
leaves (rarely up to 4). The leaves are cylindrical, 1-2.5 cm tall and up to 2 cm in diameter. As soon as the dry summer period arrives, they start to whither.
Flowers appear in spring and summer (Augustus-November), usually after the leaves have retracted. Each plant may have 1-3 inflorescences up to 20 cm tall.
This subspecies occurs widespread from the Knersvlakte in southern Namaqualand to Graaff-Reinet in the Eastern Cape on rocky slopes and flats.
If there were a list of favourite types of succulents, I’m sure the so-called window plants would rank very high. Most of these plants belong to the Aizoaceae (Mesembs), but they are also found in Bulbine and Haworthia.
When one looks up information on window leaves, one gets the impression they are all built on the same principle: the surface of the leaf tip lacks chlorophyll, the central parenchyma* reaches up to the epidermis and as a result of this combination, the leaf tip looks and acts like a window.
In a few cases however, the windows are formed differently.
It has taken me quite a while to find a place where this is described in a comprehensive as well as comprehensible way.
In Cactus & Succulent Journal (US) vol. 16, 1974, Werner Rauh published an article called Window-leaved succulents. He starts his explanation with a description of Haworthia obtusa (=cooperi) var. pilifera and uses more or less the following wording:
“The numerous fleshy leaves are nearly hidden in the substratum and we can only see the transparent, glass-like leaf tips, ending in a long hair. The transparence of the leaf tips is caused by a lack of chloroplasts**. We find the assimilation parenchyma only in the lower two thirds of the blades, but these leaf parts are not accessible to the light. The consequence of this anatomical structure is that light, necessary for assimilation, can reach the assimilation parenchyma only by passing the transparent windows. But the leaves of H. pilifera are not in the morphological sense true window leaves.”
He then moves on to Haworthia obtusa (=cooperi) var. dielsiana, saying:
” … the most remarkable feature is the behaviour of the leaves in the course of their development: young leaves are of the same shape as those of H. pilifera, but becoming older, the upper third of the lamina, which exceeds the soil surface, dies off, so that only the water parenchyma, covered by the shrunken epidermis is to be seen. The lower parts of the leaves with the assimilation parenchyma are hidden in the ground; sunlight can reach it only by passing through the water parenchyma.”
This is the same type of window formation we find in Bulbine mesembryanthoides. In Rauh’s words:
“Becoming older, the upper parts of the leaves die off, as in Haw. obtusa var. dielsiana and the result is the formation of a big window with a plane surface. The assimilating parenchyma is completely hidden in the substratum.”
We know that strong sunlight destroys the chlorophyll, which is essential for the plant’s metabolism. Window-leaved plants are hidden in the ground (at least in the hot and dry season) and sunlight can reach the assimilation tissue only through the windows, passing through the water parenchyma. This filtering process protects the plants against very strong light.
In experiments carried out with Fenestraria, it was found that the light is reduced so much that the chloroplasts will not be damaged, but stays strong enough to allow sufficient assimilation and production of organic substance.
* parenchyma is the relatively undifferentiated tissue that makes up the bulk of many plant organs and is often used for storing of water or food.
** chloroplasts are the tiny parts within plant cells that contains chlorophyll.
This is what the plants look like when the tips of the leaves start dying down.At the end of the process the plants look like this.
About 70 species of Pelargonium belong to the section Hoarea: deciduous geophytes with turnip-shaped or elongated tubers. Several of these plants have similar leaves, so one needs flowers to positively identify them.
P. luteolum possesses a large tuberous rootstock and a number of smaller tubers and
leaves 4-7 cm long and 3-12 cm wide which are dry at flowering.
The inflorescence has 2-3 branches and is up to 20-30 cm tall.
Each of the branches bears to 16 flowers, which are about 1.5 cm in diameter and pale yellow, sometimes pink, with dark red-purple lines on the two upper petals. They usually appear from November-March, but sometimes as late as May.
The plants are widespread in various -usually rocky- habitats from southern Namaqualand to Steytlerville and Mossel Bay. This is mainly a winter rainfall area, with about 100-300 mm rain per year. They seem to be especially plentiful in the Worcester-Montagu area.
The three overlapping lower petals -hiding the style and stamens-are characteristic for this species. The literature tells us that they are arranged in such a way that the lateral ones partly overlap the central one. When you look closely at the last picture, you will see that the arrangement is sometimes the other way round: here the central one of the three lower petals lies on top of the two lateral ones.
The first picture was taken 27 June 2010, the next three 22 Jan. 2016 and the last one 21 Febr. 2009.
Both species in this genus (the other one is M. stenophylla) are characterized by having thick, branched tap-roots. In this species the leaves are up to 45 mm long and about 5 mm wide. The showy flowers are often striped and appear in July/August. At least that is what the literature tells us. The photos below however were taken at the end of October. The plants occur in open patches in grasslands, fynbos or karroo vegetation from Beaufort West to Uniondale, Prince Albert and Oudtshoorn. Again: that is according to the literature, but the pictures were taken rather further west, near the northern entrance to the Seweweekspoort.
Both the genus name and the specific epithet are derived from the word gibba (hump, referring to the irregularly swollen leaves).
Plants of this species are sometimes locally abundant in the Western part of the Little Karoo and the Southwest corner of the Great Karoo (Ceres, Laingsburg, Montagu and Worcester), usually in pebbly shale or quartz patches.
They form more or less compact clumps up to 15 cm in diameter with a woody rootstock.
The pink to purple flowers are 2-3 cm in diameter and appear in early spring (August).
Here G. gibbosum is accompanied by Tanquana prismatica (on right)
It takes plants of this species 5-10 years to reach maturity and become columnar.
There are 2 subspecies, each with a number of local forms.
The plants are often locally abundant on gentle slopes and in depressions (often with quartz gravel); sometimes they also occur in shallow soil on rocky outcrops.
The flowers are white, pale yellow (often tinged red) or rarely almost red.
Subsp. columnaris is usually unbranched, with columns 2-3.5 cm wide, often as long as broad.
The inflorescence is swollen, rounded to flat and appears from May to September
The plants are monocarpic, which is another way of saying they die after flowering.
They are found in most parts of the little Karoo, the adjoining western Great Karoo and towards Calvinia. Subsp. prolifera reaches a height of 3-10 cm when in flower and forms several short branches at the base. Often these branches easily break off and take root.
The inflorescence is more or less branched and appears from July to October. After flowering, the plants often regenerate from the lower branches.
This subspecies occurs in most parts of Namaqualand and adjoining areas of Bushmanland and southwestern Namibia.
Even if one has no knowledge of Latin, it is probably easy to understand that papyracea means papery. This refers to the thin, white scales that cover the stems.
These scales are in fact modified stipules: outgrowths of the base of the leaf stalk. By reflecting and diffusing light, they act as sunshades. This effect, combined with controlled aeration*, reduces evaporation. The scales are also able to trap dew. *It has been noted that in hot, dry conditions the scales tightly overlap each other like roof tiles, whereas in cooler and therefore damper weather they can open out to some extent so that the leaves are more exposed. As Gordon Rowley in “Anacampseros, Avonia, Grahamia” (1995) remarks, it seems surprising that such an efficient adaptation has, apparently, evolved only once.
The scales are about 5 mm long and wide and hide the minute leaves.
The stems are usually about 5-8 cm long and 0.7-1 cm thick, arising from a thickened tuber. As in other Avonia species, the stems that carry flower buds grow more or less horizontal, but become erect on the day of flowering and stay that way until the seeds have been dispersed.
The scented flowers are creamy white and appear in late spring and early summer.
There are two subspecies: subsp. papyracea occurs throughout the Little Karoo and is also found in the Great Karoo, whereas subsp. namaensis occurs in southern Namibia, the Richtersveld and Bushmanland. Both subspecies seem to feel most at home amongst white quartz pebbles.
According to the literature the main difference between the two is that in the first one, the edges of the scales are entire (without any teeth or other incisions) and in the second one saw-edged to toothed.
The following pictures show plants of subsp. papyracea.
Until very recently I had never heard or seen this name; it is not even mentioned in the Illustrated Handbook of Succulent Plants (2001). Strangely enough I had seen plants of this species on several occasions, but nobody seemed to know what it was. According to some people it was a white-flowered form of B. frutescens, while others said it had been described “not long ago” as a new species. Searching through the literature did not yield concrete information either.
Ten days ago I was on a fieldtrip with members of CREW, the Custodians of Rare and Endangered Wildflowers (crew@sanbi.org.za). In the plain between Ouberg and Anysberg we came across several specimens of a white-flowered Bulbine and Marion Maclean casually mentioned the name Bulbine triebneri.
After returning home I found out that Ernst van Jaarsveld had described the species in 2001 as B. alba, but that in 2008 the new species was sunk into the older B. triebneri (Bothalia 38,1).
Of the over 70 species of Bulbine this is the only one with white flowers. It differs from its nearest relative, B. frutescens also by the soft, glaucous, more or less round leaves.
Plants are found in the Little Karoo and the southern Great Karoo, where it is locally abundant on shale ridges and scree. The species also occurs in the Eastern and Northern Cape and in southern Namibia.
In the Bothalia article it says: “The most interesting feature of this species is that the
flowers seemingly open only in the very late afternoon for two to three hours at most.”
In spite of this, the first of the pictures shown here was taken at 7.20 AM and the other three between 12.39 and 13.33 PM.
Until very recently I had never heard or seen this name; it is not even mentioned in the Illustrated Handbook of Succulent Plants (2001). Strangely enough I had seen plants of this species on several occasions, but nobody seemed to know what it was. According to some people it was a white-flowered form of B. frutescens, while others said it had been described “not long ago” as a new species. Searching through the literature did not yield concrete information either.
Ten days ago I was on a fieldtrip with members of CREW, the Custodians of Rare and Endangered Wildflowers (crew@sanbi.org.za). In the plain between Ouberg and Anysberg we came across several specimens of a white-flowered Bulbine and Marion Maclean casually mentioned the name Bulbine triebneri.
After returning home I found out that Ernst van Jaarsveld had described the species in 2001 as B. alba, but that in 2008 the new species was sunk into the older B. triebneri (Bothalia 38,1).
Of the over 70 species of Bulbine this is the only one with white flowers. It differs from its nearest relative, B. frutescens also by the soft, glaucous, more or less round leaves.
Plants are found in the Little Karoo and the southern Great Karoo, where it is locally abundant on shale ridges and scree. The species also occurs in the Eastern and Northern Cape and in southern Namibia.
In the Bothalia article it says: “The most interesting feature of this species is that the
flowers seemingly open only in the very late afternoon for two to three hours at most.”
In spite of this, the first of the pictures shown here was taken at 7.20 AM and the other three between 12.39 and 13.33 PM.
