Developmental morphology of ovules and seeds of Austrobaileyales

Abstract

Development of ovules of Illicium anisatum (Illiciaceae), Trimenia moorei (Trimeniaceae), and Austrobaileya scandens (Austrobaileyaceae) (Austrobaileyales) was observed. In Austrobaileya scandens and Trimenia moorei the outer integument is hood-shaped, while it is cup-shaped in Illicium anisatum. On the basis of a phylogeny, the ovule with the hood-shaped outer integument is suggested to be primitive in Austrobaileyales. Seed development of Austrobaileyales was also examined. In Austrobaileya scandens the seed is mesotestal, ruminated, not pachychalazal, and has a micropyle-hilum complex. In Trimenia moorei the seed is exotestal, perispermous, not pachychalazal, and has a micropyle-hilum complex and a circular cap. The seed of Illicium anisatum is exotestal, not pachychalazal, and has a circular cap. Taking the character states of other basal angiosperms into account, primitive seeds of angiosperms are inferred to have such characters as the unilayered exotestal mechanical tissue, circular cap, micropyle-hilum complex and non-pachychalazy. The inferred primitive seed is very simple, suggesting that a great diversity of seeds is established through elaboration of organs/tissues of seeds, and not through reduction as hypothesised previously. B T 0 3 0 5 6 O v u l e s a n d s e e d s o f Au s t r o b a i l e y a l e s T . Y a m a d a e t a l .

Integrating Early Cretaceous Fossils into the Phylogeny of Living Angiosperms: ANITA Lines and Relatives of Chloranthaceae

“…Doyle et al (2008) treated placentation (113) as unknown, but the basal position of the single seed in the laterally compressed fruits suggests that it had our "ventral" state (0), like the basal ovule of modern taxa such as Illicium and Myristicaceae. The cells with digitate anticlinal walls that make up the inner layer of the seed coat are very similar to those of the sclerotic mesotesta in Illicium (Oh et al 2003), which supports scoring of the mesotesta character (129) as the same state (1; see appendix for different interpretations of the mesotesta in Austrobaileyales by Yamada et al 2003). Because there is too little space between the two layers for a fleshy sarcotesta, we score this character (130) as absent.…”

“…However, both features appear to be ancestral in Nymphaeales, including Trithuria (Hamann 1975), so they do not indicate whether these seeds are from stem relatives or crown group members. Furthermore, the report by Yamada et al (2003) of a small operculum in Trimenia (see appendix) raises the possibility that this feature was once more widespread in the ANITA grade.…”

“…Yamada et al (2008) assigned a seed from the late Albian of Japan to Trimeniaceae, based on presence of a thick lignified layer that they interpreted as a multilayered exotesta (see appendix) and an operculum, a feature typical of Nymphaeales but not known in Austrobaileyales before it was reported in Trimenia by Yamada et al (2003;see appendix). Seeds resembling Illicium were described by Frumin and Friis (1999) from the Cenomanian-Turonian of Kazakhstan.…”

Prolonged embryogenesis in Austrobaileya scandens (Austrobaileyaceae): its ecological and evolutionary significance

“…(), and similar to what has been found in species of Trimeniaceae (Bachelier & Friedman, ), Schisandraceae (Yoshida, ; Friedman et al ., ), and Illiciaceae (Solntseva, ; Williams & Friedman, ). After fertilization, the diploid endosperm of A. scandens is ab initio cellular and exhibits a marked bipolar pattern of development ( sensu Floyd & Friedman, ), as in other members of the Austrobaileyales (Hayashi, ,b; Kapil & Jalan, ; Floyd & Friedman, ; Yamada et al ., ). Interestingly, we discovered an ephemeral stage during seed development when maternal starch reserves were present in the nucellus, somewhat akin to what might be expected in the very earliest stages of the development of a perisperm – as would be the case in the Nymphaeales, for example.…”

Structure of the unusual explosive fruits of the early diverging angiospermIllicium(Schisandraceaes.l., Austrobaileyales)

“…Recent studies of female gametophyte structure and evolution (Friedman, Gallup & Williams, ; Friedman & Williams, ; Williams & Friedman, ) support the position of the basal grade of angiosperms, in most of which (except Amborellaceae) the female gametophyte is four‐celled and four‐nucleate (perhaps a plesiomorphy of angiosperms; Williams & Friedman, ). Potential symplesiomorphies in ovule and seed structures were discussed for different clades of the basal grade (Doyle & Endress, ; Endress & Doyle, ), such as an endostomic micropyle (except Trimeniaceae; Endress & Sampson, ; Yamada et al ., ) and exotestal seeds in Nymphaeales, Trimeniaceae, Schisandraceae s.l. ( Illicium and Schisandraceae s.s. pro parte ) (Kolesova & Batygina, ; Melikian, 1988a, b; Melikian & Nemirovich‐Danchenko, ; Petrova, ).…”