botany

The secret of candelabra algae (Characeae)

Candelabra algae (Characeae) belong to the most endangered fresh water plants. In deep lakes they need very clear water, poor in nutrients. In shallow water regular mechanical disturbances are necessary to protect their existence because Characeae are pioneering vegetation in such places. This… read more

Concerning the evolutionary development of the blossom and fruit of the Ranunculaeeae

The fruit formation of the Ranunculaceae - evolutionarily early representatives of the angiosperms - is taken as a motif in examining the evolutiona1y path of the formation of both the angiosperm blossoms, exposed as they are to their surroundings, and… read more

Correlation of the shapes of the shoot and leaf of annual dicotyledons

That the shape of a plant changes qualitatively and quantitatively during growth was noted as early as Aristotle. He tried to understand this process with the help of four»causes«(aitia) and four»rnotions«(kinesis). He thought that the formative force proceeds from… read more

Streptocarpus with a brood leaf

In the genus Streptocarpus (Gesneriaceae) the usual generation of new leaves on the shoot is more or less replaced by a generation of new leaf parts on the bases of abundant leaves. This indicates a homology between shoot growth and leaf growth. ‚Interesting malformations are described which could help… read more

The native species of the genus Hypericum compared

In Middle Europe the genus Hypericum is divided into six sections systemizing ten Hypericnm species according to morphological characteristics. In our proposed order, Hypericum perfomtum as a mesophil perennial plant is positioned between the related hygro- and xerophil species. Within… read more