Typology of inflorescences

Abstract

Ever since the classical period of botany it has been widely recognized that the correct interpretation of the morphology of inflorescences presents a most difficult problem. This is because of the immense diversity of forms exhibited by inflorescences of angiosperms and on these their differences in habit largely depend. Since differences in the arrangement of flowers are characteristic of smaller or larger taxonomic groups of angiosperms, it is usual to include these characters, as well as other features, in the diagnosis of a plant. But this is usually done in a descriptive manner only, especially by studying and describing the mode of ramification and foliation within the flowerbearing parts of the plant. For this purpose a very elaborate descriptive terminology is generally adopted, characterizing flower systems as dichasia, racemes, spikes, umbels, panicles, capitula etc. A recent survey of this terminology and its history has been given by Rickett (1944Rickett ( , 1955.I n phytography this terminology is adequate, for here it is necessary only to give a clear portrayal of a plant, so that it will be possible to recognize it and to distinguish it from its relatives. For comparative purposes, on the other hand, such as those involved in systematics, a descriptive classification of inflorescences turns out to be insufficient. While systematics must be based on a comparison of homologous structures, it does not follow that flower-bearing parts to which a single descriptive term is a t present applied are necessarily homologous. For example the inflorescences of Onagra biennis and Plantago m j o r respectively may be termed spikes, but their morphology is, * Sea footnote on p. 220. t The term 'paracladium' is more comprehensive than the term 'enriching branch', since it refers not only to flower-bearing branches but elso includes those branches which either never produce flowers or do 80 under rare and specific conditions. Thus within the whole branching system even the innovation shoots have to be regarded as paracladia of a s p i e l type. By taking the whole branching system of a plant into consideration i n this way, and this is essential if homologiea are to be correctly interpreted, we ikd that there is an essential Werance between Troll's conception and previous attempts to elucidate the structural laws of inllorescences.

The Algorithmic Beauty of Plants

“…Unfortunately, the terms used for the various inflorescence types are not uniform in the literature. Besides a purely morphological terminology, attempts have been made to construct a "typological" terminology, expressing the "essential" features of flowering structures [144,145,157,158]. However, these terms are not generally accepted [12].…”

Floral Organogenesis in Five Genera of the Marantaceae and in Canna (Cannaceae)

“…Each bract on the florescence (an indeterminate flowering shoot bearing lateral flowers or groups of flowers and forming a repeated unit of an inflorescence, Weberling, 1965) subtends a symp o d i a l s y s t e m o f a x e s ( t h e f l o r e s c e n c e component, Andersson, 1976) each bearing a Fig. 3, 4.…”

Revisión del género Valeriana (Valerianaceae) en Sudamérica austral

“…Las especies altoandinas son de escaso porte y adquieren formas arrosetadas (V. boelckei, V. chilensis, V. descolei, V. dinorrhiza, V. macrorhiza; V. philippiana, V. radicalis, V. ruizlealii), son acaules en algunos casos (V. moyanoi, V. sedifolia,). En algunas especies la presencia de rizomas muy extendidos y ramificados facilita su propagación vegetativa, como en V. chilensis, V. fonckii, V. hebecarpa y V. philippiana, entre otras (Kutschker 2009 Borsini (1944), Larsen (1986) y Weberling (1961, 1965, 1983. El tipo de inflorescencia básico de Valeriana podría definirse como una inflorescencia monotélica truncada (Weberling 1961).…”