Questa specie staordinaria, sebbene adesso sia relativamente facile da trovare,  continua ad ispirare trepidazione e ammirazione per via delle sue foglie troncate. Pianta unica e differente per ogni collezzione.

Family:  Asphodelaceae (Aloacee - Liliaceae)

Scientific name:  Haworthia truncata var. truncata Schoenland
Published in: Václav Richtr, p. 108

Distribution: South Africa (Western Cape: Little Karoo) in Oudtshoorn area (in a number of locality, Volmoed, Vanwykskraal, Dysselsdorp etc.)

Habitat: They grow in the shade of bushes and occasionally in open areas. They grow underground with only the apex of the leaves rising above the soil surface so that they are difficult to find. This is an excellent protection against herbivores . This very singular plant has contractile leaves that will pull the plant into the ground during times of drought, leaving only the windowed tops exposed.

Etymology:The genus "Haworthia" is named after the British botanist Adrian Hardy Haworth (1767–1833)
The specific name "truncata"derives from the Latin adjective “truncatus” meaning “cut off, truncated” (The specific name implies: "squarely cut off")

Synonyms:  

• Hawhorthia truncata  Schoenl.
• Haworthia truncata spp. truncata

This desirable species, despite the fact that actually is common in cultivation, still inspires trepidation and admiration by way of its unusual truncate leaf tips. It is a superb succulent, unique, distinctive and very different for any collection

Description:  This desirable species, despite the fact that actually is common in cultivation, still inspires trepidation and admiration by way of its unusual truncate leaf tips. It is a superb plant, unique, distinctive and very different for any collection
Habit: Stemless distichous  plants, medium sized  with windowed leaves on upper margin. Solitary or slowly clumping depending on the clone (Unpredictably, some plants remain unbranched, while others readily cluster)
Leaves: The leaves look as if they have been roughly cut off at the tops and they are arranged like a fan, not a rosette. As the plant grows take on an almost crested appearance. The leaf size and thickness, of the end-areas will vary greatly from clone to clone. The surface is warty and the blunt end is transparent whit some interesting leaf markings, others are rather plain, this "lightning flash" patterns in the leaves do not come out until the plant reaches maturity.

Fenestrate leaves: This plant is a choice example of the window-leaf ( fenestrate leaf) adaptation found in many Haworthias, Mesembreanthemums and Peperomias, the translucent 'glassy' windowed apices allow light into the internal plant body rich in chlorophyll-bearing layers of cells, thereby providing a much larger assimilation area.
The windows greatly increase the photosynthesizing area by allowing light into the centres of leaves and at the same time avoiding water loss.

Contractile roots: Contractile roots  pull the this plant deeper into the soil to protect it from sun and heat during the dry season. Contractile roots are found in many plants species mainly at the base of an underground organ (bulb, corm, succulent rosette, etc.)
The contractile roots continually pull the plants deeper into the  ground as the stem elongates so the it remain subterranean or at an appropriate level in the ground.. Contractile roots are usually broad, fleshy, vertical, tapering, wrinkled looking and very distinct of the rather cylindrical fine absorbent roots and are capable of incredible effort.
In most cases, contractile roots not only produce a strong pulling force on but also push away the substratum and create a soil channel in which plant movement is made easier. For example in Haworthia the fleshy contractile roots swell with moisture in the wet season creating a space in the substrate then - after the full drying out of soil during the dry season - a considerable parts of this roots die off leaving empty spaces in the substratum that allow plant movement with minimum or no resistance, at the same time the other roots dehydrates and shrinks vertically, drawing the plant down into the ground. This is repeated early permitting the top of the plant to remain constantly at the soil level.

Notes: This species has been the subject of passionate work of breeding and selection by the Japanese, and a number of wonderful cultivars with white lacy patterns on green-grey windowed tips have been developed and propagated, and some specimens have a very unique leaf shape.

Cultivation:  Not difficult to cultivate, though it is not fast growing and takes several years to form good looking heads,  Must be repotted frequently, because every year a part of their roots die and then rots in the pot.
Watering Needs: Water regularly in the growing season, they should never dry out completely during the rest period
Frost Tolerance:  Hardy to -1 (-5)°C
Propagation: Seeds, offsets. 
Sun Exposure: it prefer locations where it's bright or in  light shade, it can tolerate shade, shelter from direct sun during the hottest hours.