Index:



L. optica
    acf 'Rubra'
    acf 'Rubragold'



Lithops optica (Marl.) N.E. Brown (1910)



       

Origin:


Collected by Dr H.W. Marloth in April 1909. Latin optica 'eye-like'.

Distribution:


Namibia, in a narrow strip some 200 km long but only about 30 km wide, extending southwards along the coast from a point about 20 km north of Lüderitz. All of this is in the Diamond Area. TL near Prince of Whales Bay (Prinzenbucht), at an altitude of 50 m and 'growing in sand covered fissures of gneiss-rocks' (C289).
Stone: Biotitic gneiss; gneiss; quartzite; quartzite and gneiss; pegmatite and gneiss; sandstone, quartzite and calcrete; limestone and calcrete; calcrete and shale. Colours grey-white, grey, pink, some yellow-brown, brown, red, greenish grey, black.

Description:


Usually recognizable by its greenish-grey colour and open windows, but plants occuring some distance inland from the coast and above the 150 m contour line tend to be somewhat larger than the coastal form and are very often quite strongly maculate.
Profile cordate-truncate; occasionally ± flat, usually distinctly convex, often humped with one side of the face lower than the other, therefore somewhat lopsided; fissure deep, 6-13 mm; lobes conjunct to somewhat divergent.
Face slightly elevated; mostly ± reniform; lobes mostly ± unequal; opaque + transluscent; smooth.
Margins distinct, regular to slightly irregular, with small indentations, but in the maculate form often very irregularly dentate or sinuate with peninsulas; inner margins usually very even.
Windows usually completely open but sometimes with a few small islands; in the maculate form often reduced to narrow irregular channels, the face then largely opaque; especially in strongly convex and humped plants, the windows often extended sharply downwards at the ends of the inner margins to form long fine points along the fissures.
Channels mainly in the maculate form, usually broad but irregular, sometimes narrow and very irregular.
Islands often absent; usually small and sparse, sometimes rather obscure, but in the maculate form, often larger, more numerous and irregular in shape.
Rubrications absent.
Dusky dots not visible.
Colours: Margins and islands opaque whitish grey, grey or beige, sometimes tinged with green, pink, blue or yellow; margins occasionally have a slightly deeper tinge at the edges of the windows. Windows and channels, various shades of transluscent greenish grey, grey or bluish grey. Shoulders as for the margins, or slightly duller.
Size: Small to medium, facial diameters up to 30 X 20 mm, mostly about 20 X 15 mm. Number of heads up to 20 or more, mostly 2-5.

Flowers:


White, very often with pink tips; very small to small, up to 20 mm Ø, mostly 12-15 mm Ø.
Seed capsules mostly 5-merous (96%), otherwise 4-merous (3%), or 6-merous (1%). Profile boat-shaped, top ± flat, sometimes slightly convex or concave, usually with a dark line, up to 1 mm wide, just below the edge. Face broadly elliptic, with hinge-rim, up to 10 X 7 mm, mostly about 7 X 6 mm.
Seeds brown; rugose 2, flecked.

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Lithops optica (Marl.) N.E. Brown (1910)


acf. 'Rubra' (1925)



   

Origin:


Collector of type plants not recorded, but Dinter reported having received specimens from Friedrich G. Eberlanz in 1923, so it is very likely that he was the first to collect them. This most attractive form was originally published as Mesem. opticum var. rubrum Tisch. in 1925, Latin rubra 'red'.

Distribution:


L. optica, acf 'Rubra' occurs only extremely rarely in colonies of the typical grey-green plants to the W, SW and S of Lüderitz.

Description:


Very distinctive in colour, but in all other respects essentially as for the type. Profile usually cordate, distinctly convex and humped. Windows usually completely open, seldom with a few small islands; often extended sharply downwards at the ends of the inner margins and drawn to fine points along the fissures.
Colours: Margins, islands and shoulders opaque milky ruby-pink. Windows transluscent light to dark ruby-red, sometimes slightly greyed.

Flowers:


White, very often with pink tips; occasionally the whole corolla may be suffused with pink or ruby-red.
Seed capsules mostly 5-merous (89%), otherwise 6-merous (7%), or 4-merous (4%). Profile boat-shaped, top slightly convex, the line below the edge usually even darker than in the type. Face broadly elliptic, with hinge-rim, up to 8,5 X 7 mm, mostly about 7 X 6 mm.
Seeds brown; rugose 2, flecked.

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Lithops optica (Marl.) N.E. Brown (1910)


acf. 'Rubragold' (2001)



Description:


Identical in appearance with L. optica, acf 'Rubra', but flowers yellow with white centre This is a most amazing and unexpected form, and we would have rejected the report if it had not come from so reliable and long-experienced a Lithops specialist as Yasuhiko Shimada.

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* Information from COLE, DESMOND T. and NAUREEN A., (2005) Lithops Flowering Stones, Cactus&Co. Libri


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