Acid methanol leaf extracts of all of the eleven species assigned to the Section Tridentalae of Artemisia by Beetle were chromatographed using a descending two‐dimensional method. Analysis of the resultant chromatographs showed that the presence or absence of any or all of three spots, in particular, blue (84/53), orange (80/50), and green (81/58), was consistently the same for any species or variety. These spots have been designated as species‐specific. Certain relationships on the basis of this evidence are postulated. Three additional spots which appeared on the chromatograms, blue (55/65), orange (51/70), and blue (53/79), seem to be characteristic of the Section Tridentatae. It is proposed that the three species which do not show these spots do not properly belong in this section. Preliminary evidence indicates that the species diagnostic spots are aglycones or free phenolics while the section‐diagnostic spots are possibly phenolic glycosides.

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Observations of the digestive glands, trigger hairs, epidermal surface, nectar glands, touch receptors, and stomata of Dionaea muscipula, the Venus's flytrap, were carried out by means of scanning electron microscopy. Previously undescribed details of the surface topography were resolved which may correlate with certain functions of the plant.

Trigger hairs of Dionaea muscipula fixed in glutaraldehyde and OsO4 were prepared for study in the electron microscope. Electron micrographs of the active zone of the trigger hair reveal three regions in which the cells differ in size, shape, and cytoplasmic content. Each region contains large numbers of protein bodies and mitochondria with densely packed tubular cristae. Vacuole‐like structures containing protein bodies or an anastomosing system of cisternae, or occasionally both, are also present. Found only in the indentation cells is a complex, whorled endoplasmic reticulum. A concentric lamellar arrangement of the endoplasmic reticulum around the vacuolar structures is often observed. The lateral walls of the indentation cells are disproportionately thick while end walls are thin. The basal walls of these cells contain many plasmodesmata. Plasmodesmata in the anticlinal and podium cells pass through constricted zones in the cell wall and are particularly numerous in the peripheral podium cells. The possible functional significance of these structures is discussed.