Definition of the concept ’Inflorescence’, with special reference to Ligneous Plants

A colloquium at the Rijksherbarium, Leyden, on September 27, 1962, held by Dr. P. Weberling, Mainz, on the subject of the interpretation of the inflorescence according to Prof. Troll’s ideas, stimulated me to reconsider this concept. It appears to me that the term inflorescence, as for example defined in Jackson’s Glossary as ”the disposition of flowers on the floral axis” is a merely phytographical concept. If it is attributed more than purely descriptive value, it should have a morphological basis. In the descriptive sense it is morphologically confusing. We call the inflorescence of Ananas or Sphenoclea a spike, but we define the flowering parts of Melaleuca, Callistemon, or Pentraphylax also as spikes, which they are, but merely by superficial appearance. In the latter cases the spike is morphologically of an essentially different nature, namely the tip of a twig, covered with closely set, solitary, lateral flowers (uniflorous inflorescences), each in the axil of a small bract, whilst vegetative growth of the tip of the twig is arrested temporarily during anthesis, to burst forth from the vegetative end bud post-anthesin.