The evolution of floral biology in basal angiosperms

Abstract

In basal angiosperms (including ANITA grade, magnoliids, Choranthaceae, Ceratophyllaceae) almost all bisexual flowers are dichogamous (with male and female functions more or less separated in time), and nearly 100 per cent of those are protogynous (with female function before male function). Movements of floral parts and differential early abscission of stamens in the male phase are variously associated with protogyny. Evolution of synchronous dichogamy based on the day/night rhythm and anthesis lasting 2 days is common. In a few clades in Magnoliales and Laurales heterodichogamy has also evolved. Beetles, flies and thrips are the major pollinators, with various degrees of specialization up to large beetles and special flies in some large-flowered Nymphaeaceae, Magnoliaceae, Annonaceae and Aristolochiaceae. Unusual structural specializations are involved in floral biological adaptations (calyptras, inner staminodes, synandria and food bodies, and secretory structures on tepals, stamens and staminodes). Numerous specializations that are common in monocots and eudicots are absent in basal angiosperms. Several families are poorly known in their floral biology.

Ancestral traits and specializations in the flowers of the basal grade of living angiosperms

“…-An often addressed feature in basal angiosperms is floral phyllotaxis (see also Endress, 1987aEndress, , 2006Ronse De Craene & al., 2003;. Some angiosperms have different phyllotaxis in the perianth and the fertile organs, such as those Magnoliaceae with whorled tepals but spiral stamens and carpels, and for this reason we have treated perianth and androecium phyllotaxis as separate characters in phylogenetic analyses (Doyle & Endress, 2000, 2010. However, there is no such intrafloral variation between whorled and spiral in the taxa considered here.…”

“…It is of interest that bisexual flowers in the ANITA grade are all protogynous, which is also the nearly universal state in magnoliids and appears to be the ancestral mechanism in angiosperms for avoiding self pollination (Bernhardt & Thien, 1987;Thien & al., 2000;Endress, 2010). Protandry evolved only in flowers with pronounced stamen filaments and (especially in monosymmetric flowers) with well developed styles.…”

“…Protandry evolved only in flowers with pronounced stamen filaments and (especially in monosymmetric flowers) with well developed styles. Such differentiation of stamens and carpels is rare in the ANITA grade and magnoliids (Endress, 2010). Carpels, angiospermy.…”

A família Nymphaeaceae no estado do Ceará, Brasil

“…Graças à sua importância ecológica (Pott & Pott 2000), cultural (Krell et al 2003;Bertol et al 2004;Endress 2010) e científica (Les et al 1991;Les et al 1999), a família tem sido abordada em diversos inventários florísticos pelo mundo (Duke 1963;Wiersema 1987;Dezhi et al 2011;Hyde et al 2012) e em análises filogenéticas (Ito 1987;Löhne et al 2007).…”

Pollination of Myristica and Other Nutmegs in Natural Populations

“…For plants in the ANA grade (the three basal lineages of angiosperms), beetles, bees, and flies are important pollinators, and pollen rewards and floral deceit are common [35,36]. Nutmegs not only have these features, but their small flower size, concave and enclosing perianths with small entrances, scented flowers, and nocturnal flowering, are all associated with beetle, thrip, and/or fly pollinators [34,[35][36][37]. The floral biology, the nature of pollination, and important pollinators of members of the nutmeg family have been elucidated by field studies of natural populations of several species of Myristica, and a review of these findings will form the basis for this report, although as we shall demonstrate, the nutmeg family remains under studied 45 years after Flach's 1966 report [22] summarizing knowledge of commercial nutmeg reproduction, during which time the study of tropical organisms has blossomed.…”