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Lithops hookeri v. subfenestrata "brunneoviolacea" C19 TL: 40 km SW of Griquatown, S.A.
 Nice form with unusually murky windowed apex slightly humped with a rich red-brown to violet coloration.
 

Description: Lithops hookeri is a medium to very large species, up to 46 X 35 mm, usually about 30 X 23 mm. with up to 10 or more heads (mostly 2-4)
Body (paired leaves): Obconical, truncate, top surface flat to slightly convex. The face is elliptical more or less equal. The fissure is shallow 3-7 mm, the lobes are conjunct.  This species is characterized by an obscure network of simple and forked groves and lines, and numerous irregular small island enclosed by groves. Margins are irregularly incise with narrow lines tapering out of the grows. This species is quite variable and the colours and face pattern varies considerably in plant from different provenance.

Lithops hookeri comprises several more or less intergrading and distinct variety:

• var. hookeri (Berg.) Schwant. (1908) Cole numbers: C110, C112, C113, C114, C118, C142B, C340 (Vermiculate form) C023, C051, C335, C336T
  Usually without windows and with rare dusky dots, but with an obscure network of simple and forked groves and lines, and numerous irregular small island enclosed by groves. Margins are irregularly incise with narrow lines tapering out of the grows. The colour of the margins and face island comprises opaque brown or buff or greyish, reddish, pinkish or orange-brown. Channels and grooves are opaque or very obscurely transluscent greenish brown or grey, greyish or brownish green, orange or reddish brown or red. Lines dull dark red. Shoulders as for the face dull grey.

• var. dabneri (L. Bol.) D.T. Cole (1965) Cole numbers C013, C085, C301
  Differs from type for a relatively frequent presence of shadowy, obscurely translucent windows. Shoulders, margins and island opaque grey or bluish, pinkish, or brownish grey or greyish brown, often slightly more intensely coloured around the margins, Channels various shades of obscurely transluscent slate-grey, dark bluish or greenish grey or greyish or brownish green. Lines dull dark red. Dusky dots dull dark greyish green.

• var. elephina (D.T. Cole) D.T. Cole (1970) Cole numbers C092, C093
  Differs from type for the wider and shallower channel and for the generally absence of rubrication.
  Margins and islands opaque grey tinged, pale pink or brown. Channels obscurely translucent greyish green, grey or greenish grey. Rubrications (if present) very obscure dull red. Shoulders opaque grey to brown.

• var. lutea (H.W. de Boer) D.T. Cole (1964) Cole number C038
  Quite the same as var. hookeri with large island and coarse network of grooves. The margins, shoulders and islands varies from opaque beige tinged with with pink, brown, yellow or orange. Channels various shades of opaque or very obscurely transluscent orange-brown, orange-red, brown, red-brown or greenish grey. Rubrications blood-red. Dusky dots dull dark greyish green.

• var. marginata (G.C. Nel) D.T. Cole (1946) Cole numbers C035, C137, C338; (Cerise form) C088; (Red-brown form) C053, C089, C154, C155, C337
  This is more variable varieti for face colours with a tendency to wider channels and more open windows. Shoulders, face margins and islands, opaque yellowish, greenish, pinkish or brownish grey, yellow or pink beige, reddish grey, the margins often obscurely banded with more intense colour. Windows and channels various shades of obscurely transluscent greyish or brownish green, greenish brown, greyish red or dark grey. Rubrications bright to dull dark red, orange-red. Dusky dots dull dark greyish green.

• var. subfenestrata (H.W. de Boer) D.T. Cole (1964) Cole numbers C021, C156, C175; (brunneoviolacea) C019
  Distingushed for having obscurely transluscent windows with very shallow channels, obscure islands, dark brownish slate colour and polished appearance. Shoulders, face margins and islands various shades of opaque brownish grey, buff or greyish, yellowish, greenish or pinkish brown; the margins often suffused with a band of more intense colour. Windows and channels various shades of obscurely transluscent dark brownish slate, brownish green.

• var. susannae (D.T. Cole) D.T. Cole (1970) Cole number C091
  This is the less reticulate form and also the smaller in smaller size. Shoulders, face margins and islands various shades of opaque cream or pale grey, often tinged with yellow, green, pink or pale brown, the margins occasionally banded with more intense colour. Channels various shades of obscurely transluscent greyish green, greenish grey, brown, or orange-brown, sometimes more intensely coloured in the margins. Rubrications obscure dull red.

Cultivars:

• Lithops hookeri cv' Envy' The plant is yellowish-green in colour, but is otherwise the same as var. hookeri.

• Lithops hookeri var. marginata cv'Shimada's Apricot' It differs from var. marginata in its pinkish apricot colour.

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Synonym: Lithops turbiniformis var.  subfenestrata

Habitat:  Lithops are an expression of particular niches, L. hookeri var. subfenestrata grows in a rocky  ground among  the equally shiny dark and implausibly shiny ironstone.

Common English Names include: Stone plant,  Living stone.

Flowers are Yellow in late summer.

Remarks: Lithops are partly subterranean, with only the clear 'window' in each leaf tip exposed above soil. A type of optical system exists whereby a layer of apical tissue rich in calcium oxalate crystals acts as a filter to intense sunlight before it reaches the thin chlorophyllous layer below. They are also called mimicry plants as they show a striking similarity to their background rocks and are difficult to detect when not in flower. These are the commonly known as pebble plants or living stones; each species is associated with one particular type of rock formation and occurs nowhere else. Its soil-embedded, subterranean growth form also reduces the need for chemical defences against herbivores.
 

Cultivation: L. hookeri is a summer growing species with dry rest period over winter. Easy to grow it tolerates a degree more excess water than some particular hydrophobic species, even so it must have a very open mineral, fast draining mix with little compost and a high degree of grit, coarse sand, small lava gravel or pebbles. Give them the maximum amount of light you are able to give them, but care should be taken about exposing them to the full blast of the sun rays in summer. 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).
The basic cultivation routine is: Stop watering after flowering. Start watering after the old leaves 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, no water when cold. Some growers fertilize frequently, some hardly ever. Keep them dry during the winter. Nearly all problems occur as a result of overwatering and poor ventilation especially when weather conditions are dull and cool or very humid. If too much water is supplied the plants will grow out of character, bloat, split and rot. Keep them in small pots as solitary clumps or as colonies in large, shallow terracotta seed pans.

Note: 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".

Photo of conspecific taxa, varieties, forms and cultivars of Lithops hookerii
 

• Lithops hookerii (Form Abrahamsdam)
• Lithops hookerii var. elephina C93
• Lithops hookerii var. lutea C38
• Lithops hookerii var. marginata "Cerise" C88
• Lithops hookerii var. subfenestrata "bruneoviolacea" C19

All the information and photos in cactus art files are now available also in the new the Encyclopaedia of Succulents. We hope you find this new site informative and useful.