Variability of male cones in Chamaecyparis as an example for Cupressaceae male cones

Abstract

SummaryIn contrast to flowers of other seed plants, male cones in Cupressaceae show a high intraspecific variability regarding the number of scales per cone and the number of pollen sacs per scale. This is the first time a qualitative and quantitative analysis of this variability is given. The variability is shown in distinct patterns. A typical pattern or diagram can be gathered from the analyses of 30 cones, which illustrate the "normal" situation and the most frequent variability (average cone diagram). However, the overlapping intersections in the cone diagrams between the species do however not allow identifications based on single male cones. A detailed study of all five species of Chamaecyparis shows that all of them can be distinguished on the basis of their average male cone diagram. A principal component analysis shows that these five Chamaecyparis species form distinct clusters. Sample cones from different positions of the tree reveal no effect within the variability of the cone diagrams. In contrast, comparison between the species and its cultivars reveals a higher variability in cultivars.

Pollen cone teratologies in Sequoia sempervirens (D. Don) Endl. and Widdringtonia nodiflora (L.) Powrie (Cupressaceae) in the light of conifer evolution

“…The cupressaceous microsporangiophores are exclusively hyposporangiate. However, the number of microsporangia per microsporangiophore varies not only between genera and species but in most taxa also within species (Pilger 1926;Neger & M€ unch 1952;Den Ouden & Boom 1965;Kr€ ussmann 1983;Page 1990;Farjon 1984;Gifford & Forster 1989;Schulz 2006;Schulz & St€ utzel 2006). However, except for the inflorescence-like pollen cones of J. drupacea, fundamental structural differences are also lacking among Cupressaceae.…”

Male Cone Evolution in Conifers: Not All That Simple

“…Male cone size varies greatly from 2 mm in Juniperus communis up to 24 cm in Araucaria rulei [10]. Morphological descriptions of male cones are frequently adopted from earlier publications, and there are a very limited number of recent publications examining the variability of conifer morphological characteristics and their modifications [11] [12]. In contrast, there has been more investigation of female cone properties [13]- [15].…”

“…The male cone was considered in early work to be a flower analogue [16], as described in Chamaecyparis [11]. Parlatore [17] equated one sporangiophore with a single flower, e.g.…”

“…This plane-like structure can be peltate, as in many Cupressaceae s. str. [11] or phyllome-like, as in Cephalotaxus [18]. Most studies consider sporangiophores to be microsporophylls or at least refer to them as microsporophylls.…”