Fig. 1.

Illustrations of different aspects of inflorescence research. (A) Compound umbel of Chaerophyllum bulbosum (Apiaceae) with umbellets composed of hermaphrodite and small (functionally) male flowers. (B) The branching pattern of Actinocephalus bongardii (A. St.-Hil.) Sano (Eriocaulaceae). The grey branches are decaying or had already fallen at the time this diagram was made. Graphics in this manor facilitate comparisons between species and allow visualization of morphological and developmental patterns. (C–E) Development of a floral unit meristem (FUM) producing the compound head of Echinops bannaticus Rochel ex Schrad (Asteraceae). Scale bar = 200 µm and applies to all three images. (C) Young FUM with characteristic apex lacking primoridia. (D) Small head primordia (arrowheads) are produced by meristem fractionation at the base of the FUM. (E) Young double head after fractionation into heads ‘H’ and before flower production. (F–I) Basic inflorescence types according to the ontogenetic concept of inflorescences: (F) panicle; (G) botryoid; (H) raceme; and (I) compound raceme. (J) Young inflorescence of Posidonia (Posidoniaceae). Green = flower-subtending bracts (FSBs); yellow = stamen connective; orange = thecae; red = carpel. The FSBs are delayed in development in this species, and become clearly visible only at anthesis. Scale bar = 1 mm. (K) Top view of a heterogamous inflorescence of Anacyclus clavatus (Asteraceae) with zygomorphic ray flowers and tubular flowers. (L) Lateral view of a homogamous inflorescence of Anacylus monanthos (Asteraceae) with tubular flowers in anthesis. (M) Inflorescence of Cornus canadensis L. f. (Cornaceae).