ABSTRACT. Cyperus esculentus (Yellow Nutsedge) is a troublesome weed with broad infraspecific variation. A growing experiment was performed in which diverse clones were raised under different environmental conditions. Sixty five characters were measured and evaluated based upon their sensitivity to environmental and clonal differences. Of these, 17 proved to be sufficiently reliable for taxonomic purposes. They concern size and shape of floral parts rather than dimensions of spikes, which were until now thought to be the diagnostic characters. Herbarium material from all continents where C. esculentus is present was studied, including type material of varieties; 70 plants were selected, the 17 parameters measured, and the data analysed by multivariate techniques. Four clusters were distinguished, which appeared to broadly represent four varieties described by Kiikenthal in 1935; three of his seven varieties were rejected, var. cyclolepis, var. nervoso-striatus, and var. sprucei. The four remaining varieties are discussed and described, and a key is given for their identification. They are var. esculentus, var. leptostachyus, var. macrostachyus, and var. heermannii.

Summary In experiments with models and a Petunia cultivar a hawkmoth makes its initial approach at about the same level as the flower. In Lilium martagon L., after flower opening, the style curves towards the direction of maximum light intensity. A hawkmoth comes into contact with the stigma at the beginning of its visit. Thereafter, while drinking from the individual nectaries on each petal, the visitor picks up pollen from the anther in front of the petals. During the initial approach to Crinum jagns (Thomp.). Dandy flowers a hawkmoth touches only the stigma, which is in front of the anthers. Anthers contact the visitor's body only during drinking. Then the moth leaves the flower by flying upwards and does not touch the stigma again. Thus there is evidence that in two Lilüflorae, the combination of the moth‐behaviour with the flower structure might reduce self‐pollination.

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fragrans (L.) Ker Gawler is revised, similar species are critically compared and several of them, notably D. deremensis Engl. and D. deisteliana Engl. are reduced into synonymy. A formal classification with standard specimens for cultivated material currently in commerce is proposed.

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