Klaus Kubitzki

The 50th volume of Progress in Botany appears in new guise. In cooperation with Springer-Verlag we have changed from the less attractive typewriter composition to the direct reproduction of a manuscript which was writ­ ten by means of a text editing system and produced by a laser printer. We, the editors, should like to take the appearance of Volume 50 as the occasion for a few short remarks. Our younger readers are perhaps not aware that our Book Series was founded in 1931 by Fritz von Wettstein, based on the following thoughts and considerations, aptly formulated by him in the Preface to the first volume. "One of the greatest dangers threatening progress in the science of botany is the absolutely unbelievable growth in volume of the literature. The quality of journals, books and individual works that are daily sent to us makes it impossible for anyone person to maintain a general view of the progress made in botany in all the specialized fields, let alone to find time for results from associated su bjects. For varying reasons, every botanist must find this state of matters insupportable. Let us endeavor, in the general interest, to retain a wide background of knowledge, and not become limited specialists. The vitally necessary connections between the specialized fields can only flourish, or even exist, if the general view of botany as a whole can be maintained.

With one new volume each year, this series keeps scientists and advanced students informed of the latest developments and results in all areas of botany. The present volume includes reviews on structural botany, plant physiology, genetics, taxonomy, and geobotany.

Der Senior unserer Herausgebergemeinschaft HEINZ ELLENBERG hat sich leider aus der Redaktion zuruckgezogen. Nach dem Tode von ERNST GXUMANN hatte er 1963 (ab Band 26) zusammen mit ERWIN BUNNING die Herausgeberschaft der "Fortschritte der Botanik" ubernommen. Seiner Aufgeschlossenheit und auch seiner Initiative ist die dann spater erfolgte Erweiterung des Herausgebergremiums und die damit verbundene inhaltliche Umgestaltung zu verdanken. In seiner nunmehr fast zwanzigjahrigen Betreuung des Abschnittes "Geobotanik" hat er dazu beigetragen, daB dieses Teilgebiet zu einer wesentlichen Saule unserer Reihe geworden ist. Herausgeber und Verlag mochten ihm fur seine Redaktionsarbeit danken und hoffen, daB Herr ELLENBERG ihnen auch weiterhin in alter Freund- schaft verbunden bleibt. An seiner Stelle . hat von diesem Band ab Herr MICHAEL RUNGE die Schriftleitung des Kapitels Geobotanik ubernommen. Die Herausgeber Contents A. MORPHOLOGY I. Cytology a) General and Molecular Cytology. By ANTHONY W. ROBARDS *** 1. Root Hairs ******************************************* 1 a) Development and Structure of Root Hairs *********** 1 b) Microbial and Other Associations with Root Hairs ** 3 2. Cytoplasmic Streaming ******************************** 6 a) General Experimental Effects on Cytoplasmic Streaming ***************************************** 7 b) Effects of Cytochalasin B on Cytoplasmic Streaming ***************************************** 8 c) Effects of Light and of Growth Regulators on Cytoplasmic Streaming ***************************** 9 d) The Role of Calcium in Cytoplasmic Streaming ****** 10 e) General Observations on Cytoplasmic Streaming ***** 11 3. Calmodulin ******************************************* 1 2 References ********************************************** 14 b) Special Cytology: Cytology and Morphogenesis of Higher Plant Cells - Phloem. By H. -D.