The inflorescences are loose, not dense; subtending floral leaves have a sparse covering of capitate-sessile glandular trichomes; perigonal bracts have a relatively sparse covering of capitate-stalked glandular trichomes.
Its inflorescences are somewhat compact; subtending floral leaves have an abundant covering of capitate-sessile glandular trichomes; perigonal bracts express a moderate density of capitate-stalked glandular trichomes.
Inflorescences are loose; subtending floral leaves have a sparse covering of sessile glandular trichomes; perigonal bracts have few capitates-talked glandular trichomes and many cystolith trichomes.
Inflorescences are loose, not dense; subtending floral leaves have a sparse covering of capitate-sessile glandular trichomes; perigonal bracts (i.e., bracteole, calyx) have a relatively sparse covering of capitate-stalked glandular trichomes.
A perigonal bract (sometimes called a floral bract) subtends each female flower, and grows to envelop the fruit (this is important in narcotic resin production, and additional detail is given in the "Evolution of Narcotic Drug Production Under Domestication" section).
The secretory glands responsible for producing narcotic compounds are present in high density on the perigonal bracts, and these often glisten under strong light, also contributing to a whitish appearance of the female inflorescence.
Maximizing branch production is desirable as this maximizes flower production, the perigonal bracts around the female flowers producing most of the narcotic chemicals that are desired.
As discussed in the "Evolution of Essential Oil Production Under Domestication" section, a very recent market has developed for the production of essential (volatile) oil, a product substantially from the perigonal bracts, exactly the same source for narcotic drugs.
Hemp seeds contain virtually no THC, but if improperly processed, THC contamination can result from contact of the seeds with the resin secreted by the epidermal glands on the leaves and floral parts, and also by the failure to sift away all of the perigonal bracts (which have the highest concentration of THC of any parts of the plant) that cover the seeds (Ross et al., 2000).
The secretory glands differ notably in density on different organs of the plant (high concentrations occur on the lower surface of the young leaves, on young twigs, on the tepals, and especially on the perigonal bracts (Fig.
(2009a) provide evidence that CBC is present in substantial amounts in juvenile plants and declines with maturation; these authors found variants in which CBC persisted into maturity, and noticed that this is associated with a reduced presence of perigonal bracts and secretory glands.
saliva is equivocal." The glands and consequently the resin that is secreted are concentrated on the abaxial ("lower") side of the leaves (the same is time for the perigonal bracts in the inflorescence); it hardly makes sense for a sunscreen to be present on the shaded lower side of the foliage rather than the exposed upper side, and employing a resinous sunscreen seems quite speculative in view of the fact that plants commonly use several other strategies for reducing the intensity of solar radiation (see, for example, Small, 2014a).