| Abstract: | A total of 36 species, varieties and hybrids from nine genera of Scandinavian Caryophyllaceae with pantoporate pollen grains have been investigated. Habrosia spinuliflora, a non-Scandinavian plant with pantoporate pollen grains, has also been investigated. Diagnoses (p. 71–80) and photomicrographs (including some photopalynograms) are provided. Measurements, etc., are given in tabular form (Tab. 1, p. 68). The smallest grains were found in Gypsophila muralis (24 μ) and Habrosia spinuliflora (27 μ), the largest in Agrostemma githago (63 μ) and Stellaria palustris (60 μ). The number of apertures ranges from 31–37(–45) in Agrostemma githago, Lychnis flos-cuculi and Melandrium album to 12 in Scleranthus perennis, Gypsophila fastigiata, Dianthus deltoides and several species of Stellaria etc. Thin sections of pollen grains in four species have been described (p. 81). Two main types of arrangement of bacula have been encountered. One type has through bacula, connecting nexine and tegillum (e.g. in Silene, Lychnis, Viscaria, etc.). In the other type the bacula are of two different lengths: some connect nexine and tegillum, others are shorter, hanging from the tegillum half-way towards the nexine (e.g. in Stellaria and Dianthus). The nexine seems to consist of a homogeneous, undifferentiated layer. Electron micrographs of pollen grains in seven species have been made (Pl. 17–20). In Melandrium intergrading pattern types have been observed. M. viscosum has a pattern similar to that in Silene (M. viscosum should, therefore, no doubt be referred to as Silene viscosa). M. album has tetrate grains with large spinules. M. angustiflorum shows a pattern transitional between tetrate-punctitegillate and intectate-reticulate. M. noctiflorum, M. rubrum and M. apetalum have reticulate pollen grains. The hybrid M. album × rubrum has characters from both parental stocks. The pollen grains in Stellaria holostea (Pl. 13: 9–13) deviate from those in the other Stellaria species, whereas Stellaria aquatica (formerly Malachium aquaticum) shows a close morphological similarity with the other species of Stellaria (except S. holostea) It should, therefore, probably better be retained in Stellaria. A key for identification is found on p. 86. |
