Morphological features, trichomes

Plants have developed various mechanisms of defense against phytophagus Insects. Two defensive morphological features are trichomes and glands. Trichomes may be halr-llke or glandular. 

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). 

In addition to plant chemistry, morphological features of the host plant have also been shown to affect parasitoids and predators. However, with the exception of trichomes, these effects have been studied less than chemical effects. Both glandular and nonglandular trichomes have been widely reported to influence the effectiveness of natural enemies (17-18). Although nonglandular trichomes have been shown, in some cases, to impede searching by some parasitoids (19-20) and predaceous hemiptera and coleoptera (21-23), the effect is by no means universal (24-25). 

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