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Lithops helmutii

Lithops helmutii


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Succulentopedia

Lithops helmutii (Living Stones)

Lithops helmutii is a stemless succulent with a pair of fleshy leaves. They are up to 1.2 inches (3 cm) tall, not completely fused, translucent, very…


Lithops helmutii - garden

Origin and Habitat: It is found only in a small area between Steinkopf-Arrabies Steinkopf-Kinderlê, Namaqualand Republic of South Africa.
Type Locality: North East of Steinkopf, South Africa.
Habitat: Lithops helmutii grows in the shelter of rocks in an essentially winter rainfall climate. The substrata is mainly composed by translucent white, red-stained and brownish quartzite. The outstanding characteristic of these small succulents is their highly efficient camouflage. Only the upper few mm or so of the plant usually protrudes above the soil and it is often nearly buried by the detritus accumulated about it. The fleshy leaves are can hardly be distinguished from the gravels among which the plant grows and one can search diligently in places where they are known to exist without ever finding them.

Description: Lithops helmuti is one of the few naturally occurring green Lithops species with a large semi transparent to transparent window. It has a pair of plump leaves, which are bright green marked with grey and with an oblique upper surface.
Habit: The plants are stemless, perennial succulents, with solitary or clustered bodies up to 3 cm hight, usually in clumps of 5-6 heads, but may occasionally forms large clumps with more than 26 heads. Each heads consists of a single, simple, fleshy body which is split into two parts by a deep fissure. From this cleft a single flower blooms when climatic conditions are favourable. A fresh pair of leaves grows every year almost as if a new plant emerges between the old leaves.
Bodies (paired leaves): Small to medium, facial diameters about 20-30 long 15-19 mm in width, turbinate, leaves not completely fused often bicuneate in profile, fissure deep, lobes obliquely convex, sometimes tapering to a point, soft-skinned, often wrinkled, unequal in size window conspicuous, sometime reduced by islands and marginal indentations, pale green, translucent, very light-green, mottled more or less with pale-grey, creamy-grey, sometimes only a few specks. Outer margin irregularly lobed, sometimes denticulate inner margin usually straight, plain, sometimes also denticulate.
Flowers: Golden yellow with white centre (or completely white), diurnal opening in the afternoon and closing at sunset. The flower is usually about the same dimension as the plant itself (up to 33 mm in diameter).
Blooming season: Autumn, usually in April and May in habitat. In general appearance the blossoms are very similar to the Mesembryanthemurn or ice-plant (to which they are closely related).
Fruits: Capsules mostly 5-chambered. Profile boat-shaped, top flat or convex. Face elliptic to round.
Seeds: Minuscule, light yellow-brown.
Related species: L. helmutii is somewhat similar to Lithops comptonii which has top of leaves strongly convex, characterized by large, green, grey brown, plum coloured or purplish windows which contains few pale island.

Subspecies, varieties, forms and cultivars of plants belonging to the Lithops helmutii group

Notes: Lithops helmutii is considered to be a rather primitive Lithops form, the green, soft-skinned, leaves not completely fused presumably represent some of the most primitive leaf condition within the genus.

Bibliography: Major refences and further lectures
1) Heidrun E. K. Hartmann “Aizoaceae F – Z” Springer 2002
2) Achim Hecktheuer “Mesembs, mehr als nur Lithops” Books on Demand GmbH Norderstedt. 2008
3) Desmond T. Cole & Naureen A. Cole, Uwe Beyer, Yves Delange “Les Lithops” SUCCULENTES Spécial 2008 AIAPS (now Terra seca). 2008
4) Desmond T. Cole & Naureen A. Cole “LITHOPS Flowering Stones” Cactus & Co. Libri. 2005
5) Yasuhiko Shimada “The Genus Lithops” Dobun Shoin. 2001
6) Rudolf Heine “Lithops - Lebende Steine” Neumann Verlag. 1986
7) Bernd Schlösser “Lithops – Lebende Steine” Praktische Anleitung für die Zimmerkultur. BussinessPoint MEDIA. 2000
8) Steven A. Hammer “Lithops – Treasures of the veld” British Cactus and Succulent Society. 1999
9) Desmond T. Cole “Lithops – Flowering Stones” Acorn Books 1988
10) Rudolf Heine “Lithops – lebende Steine” Neumann Verlag. 1986
11) David L. Sprechman “Lithops” Associated University Presses, Inc. 1970
12) Gert Cornelius Nel “Lithops” Hortors Limited, South Africa 1946
13) Edgar Lamb "The illustrated reference on cacti and other succulents" Blandford Press. 1978
14) Christopher Brickell, Royal Horticultural Society "RHS A-Z Encyclopedia of Garden Plants: K-Z., Volume 2" Kindersley, 2008
15) G. C . Nel “Lithops: Plantae succulantae, rarissimae, in terra obscuratae, e famailia Aizoaceae, ex Africa australi” Hortors Limited, 78, Bree Street, Cape Town, South Africa 1946
16) Margaret Martin, Peter Chapman “A gardner's guide to cacti and succulents: how to grow these fascinating plants in the home and greenhouse : featuring 150 species” Salamander Books, Limited, 1988
17) CACTUS & Co, Vol. X, 1, pp 57-59 (2006)


Lithops helmutii Photo by: Valentino Vallicelli
Lithops helmutii Photo by: Valentino Vallicelli
- EH65 ex TL, North of Steinkopf, South Africa Photo by: Valentino Vallicelli

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Cultivation and Propagation: The Lithops (a.k.a. Living Stones) are some of the world's most fascinating plants and are sought by the collector of succulent plants. Paying attention to the particular growing requirement of Lithops is especially important. If you provide the Lithops with the right conditions, they will reward you with their unique shape, size, colour and a proliferation of blooms in autumn. However, Lithops are tricky plants that are very particular about their growing conditions and require the right maintenance in order to keep happy. But don't be afraid even the best growers have plants that mysteriously dry up, or leave during the night. While Lithops are picky about their care, if you are patient and remember the basics, your efforts will be rewarded. Being small plants, a representative collection can be grown on a patio table, a sunny windowsill or a shelf in the greenhouse.
Growing rate: Slow growing for a mesemb.
Soil: They grow best in an open mineral, sandy-gritty soil and requires good drainage as they are prone to root rot. They can grow outdoor in sunny, dry, rock crevices (protection against winter wet is required) They can also be cultivated in alpine house, in poor, drained soil.
Repotting: They may stay in the same pot for many years. Plants grown in larger containers have frequently relatively poor flowers. Flowers might improve when the plants are given their own, small individual pots.
Watering They Require little water otherwise the epidermis breaks (resulting in unsightly scars). The basic cultivation routine is: Stop watering after flowering. Start watering after the old leaves are completely dry (usually late March or Early April). Water freely during the growing season, soak the compost fully but allow it to dry out between waterings. In the winter season the plant doesn’t need watering, the plant in this time extracts water from the outer succulent leaves, allowing them to shrivel away, relocating water to the rest of the plant and to the new leaves that form during this period. If grown in a container, bottom watering by immersing the container is recommended. Water sparingly only when warm, no water when cold. Nearly all problems occur as a result of overwatering and poor ventilation, especially when weather conditions are dull and cool or very humid. They must have very dry atmosphere.
Fertilization: Feed them once during the growing season with a fertilizer specifically formulated for cactus and succulents (high potash fertilizer with a dilute low nitrogen), including all micro nutrients and trace elements diluted to ½ the strength recommended on the label. They thrive in poor soils and need a limited supplies of fertilizer to avoid the plants developing excess vegetation, which is easily attacked by fungal diseases. Some growers fertilize frequently, some hardly ever. However, for the highly succulent mesembs, (Lithops, Conophytums, etc.) fertilization is not really necessary.
Light: They prefer a very bright situation and in winter they need the maximum amount of light you are able to give them, but keep more cool and partially shaded in summer. The only exception to this is seedlings in their first year that enjoy a shades place. Such tiny plants can easily get scorched or broiled and their appearance spoiled (this may not matter in the wild, where the Lithops have probably shrunk into the ground and becomes covered with sands). Outdoor (Lithops prefer full sun, with some shade in the hottest summer months. High levels of light are needed in autumn to flower and for good plant development. The low intensity of sun light during the growing season of this species generally prevents the white flower flowers from opening.
Special Advice: Lithops are best planted in a sunny and airy part of the greenhouse, and not too close to the glass roof or sides of the house as the plants can overheat during hot spells.
Hardiness: They require a minimum temperature 5°C (But will take a light frost and are hardy down to -7° C for short periods if they are in dry soil). USDA zones 9A – 11.
Uses: Container, rock garden.
Pests & diseases: Lithops may be attractive to a variety of insects, but plants in good condition should be nearly pest-free, particularly if they are grown in a mineral potting-mix, with good exposure and ventilation. Nonetheless, there are several pests to watch for:
- Red spiders: they may be effectively rubbed up by misting the vulnerable plants every day.
- Mealy bugs: occasianlly they develop aerial into the new leaves and flowers with disfiguring results, but the worst types develop underground on the roots and are invisible except by their effects.
- Sciara Flies: they are one of the major problems for seedlings. It is a good practice to mulch your seedlings with a layer of grit, which will strongly discourage the flies.
- Scales, thrips and aphids: (they are rarely a problem.)
It is wise to treat your whole collection with a systemic insecticide twice a year in spring and autumn.
- Rot: it is only a minor problem with mesembs if the plants are watered and “aired” correctly. If they are not, fungicides won't help all that much.
Remarks: After flowering in the autumn and extending through winter season the plant doesn’t need watering, but they will still be growing, the new bodies will be increasing in size extracting water from the outer succulent leaves, allowing them to shrivel away. In fact the plant in this time extracts water and nutrient stored in the outer succulent leaves, allowing them to dehydrate relocating the water to the rest of the plant and to the new leaves that form during this period until the old leaves are reduced to nothing more than "thin papery shells".
Propagation: Seed or (or rarely) cuttings. The small seeds can be sown in pots of fine, well-drained sand, any time during the spring and summer months when temperatures are warm. Cover the seeds with a very fine layer of grit and water from below with a fungicide to prevent damping off. For the first 3-4 days cover the pots with a sheet of glass/clear perspex to keep the humidity levels high. Remove the glass and replace it with light shadecloth and mist once or twice a day for the next two weeks after which most seeds should have germinated. From then on mistings can be reduced to every second and then every third day as the little plants grow. Take the cuttings from a grown-up mother plant. Each cutting must contain one or more heads along with a fraction of root and permit them to dry out a couple of days, lay the cuttings on the soil and insert the stem end partially into the soil. Try to keep the cutting somewhat upright so that the roots are able to grow downward. It is relatively difficult to root Lithops from cuttings and generally pointless as well, so quick are they from seed.
Comment: Improvement of Lithops characteristics: Some growers (but not all!!) think it is very intriguing to reinforce any characteristic of cultivated Lithops of by crossing two similar selected plants and then back-crossing with the mother plant. This way we can eventually get some interesting results. Of course, many of the nicest Lithops we grow in cultivation have already been selected over time. However many Lithops are already nice plants which can’t really be improved, on the other hand one could try to improve the colour or the markings etc. Now if we have two particular plants we may attempt to breed between them and can maybe get a whole improved population and then select some better offspring to continue the selection.
Seed production: Plants can be hand pollinated, using a small paint brush. Remember always to cross different clones as the plants are self-sterile. The seed will remain viable for many years provided it is stored in a cool dry place.


Contents

Individual Lithops plants consist of one or more pairs of bulbous, almost fused leaves opposite to each other and hardly any stem. The slit between the leaves contains the meristem and produces flowers and new leaves. The leaves of Lithops are mostly buried below the surface of the soil, with a partially or completely translucent top surface known as a leaf window which allows light to enter the interior of the leaves for photosynthesis.

During winter a new leaf pair, or occasionally more than one, grows inside the existing fused leaf pair. In spring the old leaf pair parts to reveal the new leaves and the old leaves will then dry up. Lithops leaves may shrink and disappear below ground level during drought. Lithops in habitat almost never have more than one leaf pair per head, presumably as an adaptation to the arid environment. Yellow or white flowers emerge from the fissure between the leaves after the new leaf pair has fully matured, one per leaf pair. This is usually in autumn, but can be before the summer solstice in L. pseudotruncatella and after the winter solstice in L. optica. The flowers are often sweetly scented.

The most startling adaptation of Lithops is the colouring of the leaves. The leaves are fenestrated, and the epidermal windows are patterned in various shades of cream, grey, and brown, with darker windowed areas, dots, and red lines, according to species and local conditions. The markings function as remarkable camouflage for the plant in its typical stone-like environment. As is typical of a window plant, the green tissue lines the inside of the leaves and is covered with translucent tissue beneath the epidermal windows.

Lithops are obligate outcrossers and require pollination from a separate plant. Like most mesembs, Lithops fruit is a dry capsule that opens when it becomes wet some seeds may be ejected by falling raindrops, and the capsule re-closes when it dries out. Capsules may also sometimes detach and be distributed intact, or may disintegrate after several years.

Lithops occur naturally across wide areas of Namibia and South Africa, as well as small bordering areas in Botswana and possibly Angola, from sea level to high mountains. Nearly a thousand individual populations are documented, each covering just a small area of dry grassland, veld, or bare rocky ground. Different Lithops species are preferentially found in particular environments, usually restricted to a particular type of rock. Lithops have not naturalised outside this region.

Rainfall in Lithops habitats ranges from approximately 700 mm/year to near zero. Rainfall patterns range from exclusively summer rain to exclusively winter rain, with a few species relying almost entirely on dew formation for moisture. Temperatures are usually hot in summer and cool to cold in winter, but one species is found right at the coast with very moderate temperatures year round.

Lithops are popular house plants and many specialist succulent growers maintain collections. Seeds and plants are widely available in shops and over the Internet. They are relatively easy to grow if given sufficient sun and a suitable well-drained soil.

Normal treatment in mild temperate climates is to keep them completely dry during winter, watering only when the old leaves have dried up and been replaced by a new leaf pair. Watering continues through autumn when the plants flower and then stopped for winter. The best results are obtained with additional heat such as a greenhouse. In hotter climates Lithops will have a summer dormancy when they should be kept mostly dry, and they may require some water in winter. In tropical climates, Lithops can be grown primarily in winter with a long summer dormancy. In all conditions, Lithops will be most active and need most water during autumn and each species will flower at approximately the same time.

Lithops thrive best in a coarse, well-drained substrate. Any soil that retains too much water will cause the plants to burst their skins as they over-expand. Plants grown in strong light will develop hard strongly coloured skins which are resistant to damage and rot, although persistent overwatering will still be fatal. Excessive heat will kill potted plants as they cannot cool themselves by transpiration and rely on staying buried in cool soil below the surface. Commercial growers mix a mild fungicide or weak strength horticultural sulfur into the plant's water to prevent rotting. Lithops are sensitive to watering during hot weather, which can cause the plants to rot in habitat the plants are often dormant when the temperatures are high, doing most of their growing during the cool months of the year. Low light levels will make the plants highly susceptible to rotting and fungal infection. [2]

Propagation Edit

Propagation of Lithops is by seed or cuttings. Cuttings can only be used to produce new plants after a plant has naturally divided to form multiple heads, so most propagation is by seed. Lithops can readily be pollinated by hand if two separate clones of a species flower at the same time, and seed will be ripe about 9 months later. Seed is easy to germinate, but the seedlings are small and vulnerable for the first year or two, and will not flower until at least two or three years old.

The first scientific description of a Lithops was made by botanist and artist William John Burchell, explorer of South Africa, although he called it Mesembryanthemum turbiniforme. In 1811 he accidentally found a specimen when picking up from the ground a "curiously shaped pebble". [9] Unfortunately his description is not detailed enough to be sure which Lithops he had discovered and the name Lithops turbiniformis is no longer used, although for many years it was applied to what is now known as Lithops hookeri.

Several more Lithops were published as Mesembryanthemum species until in 1922 N E Brown started to split up the overly large genus on the basis of the capsules. The genus Lithops was created and dozens more species were published in the following decades. Brown, Gustav Schwantes, Kurt Dinter, Gert Nel, and Louisa Bolus continued to document Lithops from across southern Africa, but there was little consensus on the relationships between them, or even which populations should be grouped as species. As recently as the 1950s, the genus was little known in cultivation and not well understood taxonomically.

In the 1950s, Desmond and Naureen Cole began to study Lithops. They eventually visited nearly all habitat populations and collected samples from approximately 400, identifying them with the Cole numbers which have been used ever since and distributing Cole numbered seed around the world. They studied and revised the genus, in 1988 publishing a definitive book (Lithops: Flowering Stones) describing the species, subspecies, and varieties which have been accepted ever since.

Because their camouflage is so effective, new species continue to be discovered, sometimes in remote regions of Namibia and South Africa, and sometimes in well-populated areas where they simply had been overlooked for generations. Recent discoveries include L. coleorum in 1994, L. hermetica in 2000, and L. amicorum in 2006.

Many of the species listed have named subspecies or varieties and some have many regional forms identified by old names or habitat locations. Identification of species is primarily by flower colour and leaf patterns.

Lithops [10]
Specific epithet Meaning
amicorum [11] of the friends
aucampiae named after Juanita Aucamp
bromfieldii named after H. Bromfield
coleorum named after Desmond & Naureen Cole
comptonii named after Prof. Robert Harold Compton
dinteri named after Moritz Kurt Dinter
divergens divergent lobes
dorotheae named after Dorothea Huyssteen
francisci named after Frantz de Laet
fulviceps (a.k.a. lydiae) tawny head
gesineae named after Gesine de Boer
geyeri named after Dr. Albertus Geyer
gracilidelineata thin lined
hallii (a.k.a. salicola var. reticulata) named after Harry Hall
helmutii named after Helmut Meyer
hermetica named after the location 'hermetically sealed', Sperrgebiet
herrei named after Adolar 'Hans' Herre
hookeri (a.k.a. dabneri, marginata, turbiniformis var. lutea) named after Sir Joseph Hooker
julii (a.k.a. fulleri) named after Dr. Julius Derenberg
karasmontana named after the Great Karas Mountains
lesliei named after T. N. Leslie
localis (a.k.a. terricolor, peersii) of a place
marmorata (a.k.a. diutina, framesii, umdausensis) marbled
meyeri named after Rev. Gottlieb Meyer
naureeniae named after Naureen Cole
olivacea olive-green
optica (a.k.a. rubra) eye-like
otzeniana named after M. Otzen
pseudotruncatella had been confused with Conophytum truncatum (a.k.a. Mesembryanthemum truncatellum)
ruschiorum named after Rusch family
salicola salt-dweller
schwantesii named after Gustav Schwantes
vallis-mariae named after the location Mariental (Latinised)
verruculosa warty
villetii (a.k.a. deboeri) named after Dr. C. T. Villet
viridis green
werneri named after Werner Triebner

Lithops sp. Blooms emerge between the leaves in autumn.


Watch the video: How I take care of Lithops plants