Trichome unicellular

Botanically, Cannabis sativa can be identified on the basis of its gross morphological features and, more importantly, by the presence of microscopic structures on the surface of the plant, namely the trichomes. At the macro-morphological level, it has a square stem, with four comers, and has palmate leaves with serrated edges. These are the characteristics with which most people are familiar. Microscopically, three types of trichome are observed, namely the glandular trichomes (Plate 4.1), unicellular trichomes (Plate 4.2) and cystolithic trichomes (Plate 4.3). 

The glandular trichomes are the structures in which the cannabis resin is pro-dnced. These can be fonnd on the underside of the leaves, and occasionally on the stems, but are mainly associated with the flower structures, with female plants being particularly rich in such structures. The unicellular trichomes are found all over the plant, but interestingly, only point up the plant. The cystolithic trichomes are found all over the plant and may have oxalic acid crystals visible within their bases. If aU of these trichomes are found together, then the plant material can be definitively identified as Cannabis saliva, since no other plant displays such a combination [5]. However, some plants possess trichomes which may be confused with those present on Cannabis sativa [6, 7] and care should thus be taken in definitive identification. 

Fig. 9. Cross section of a bract from the fruiting plant a, cystolith hair A large grandular hair with several cells in head and stalk c, head of one of the large glandular hairs d, small glandular hair with bicellular head artd unicellular stalk e, thick walled conical trichomes f, large developing glandular hair i stalk of a large glandular hair h, palisade cell /, cluster crystal / parenchymal cell /r, stomata. (Reprinted by permission, from Joyce and Curry, The Botany and Chemistry of Cannabis, 1970. Drawn by D. Erasmus.)...

The simplest cyanobacteria are unicellular rods or cocci, which reproduce by binary fission or budding (a few species)., Many cyanobacteria have a filamentous structure. The filament of cells, called trichome, elongates by intercalary division and reproduces by breaJcage. The trichome can be composed only of vegetative cells. Some vegetative cells are converted into non-reproductive cells known as heterocysts with a special physiological function. 

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