caa a22 4500 475807146 CHVBK 20180406123750.0 cr unu---uuuuu 170329e20000901xx s 000 0 eng 10.1007/BF00985044 doi (NATIONALLICENCE)springer-10.1007/BF00985044 Schölch Annette née Thorspecken, Langgewann 22, D-69121, Heidelberg, Federal Republic of Germany aut Relations between submarginal and marginal sori in ferns [Elektronische Daten] I. The sori of selected Hypolepidaceae and Dennstaedtiaceae [Annette Schölch] In contrast to the generally favoured hypothesis that the marginal position of sporangia and sori is the primitive condition, Hagemann (e.g. 1984a) holds the view that the superficial position of reproductive organs is primitive. Marginal reproductive organs correlate with a distinct succession of a vegetative and a reproductive developmental phase in the sporophyll ("phase differentiation in leaf development”). Since phase differentiation means an increase in complexity, marginal reproductive organs are considered advanced. In order to examine the relations between submarginal and marginal sori in the light of Hagemann's hypothesis, various soral forms of ferns were analysed using the methodological framework of construction morphology sensu Weber (1958). The sorus is regarded as a reproductive region of the leaf surface that comprises not only the sporangia but also the receptacle as an essential component. The growth pattern of the receptacle, the developmental succession of the sporangia, and the formation of the indusia lead to the recognition of several sorus types. In the present paper the "basipetal marginal sorus” is presented and defined as the combination of (a) a ridge-, cushion-, or rod-shaped receptacle, (b) a basipetal sequence of sporangia initiation, and (c) the presence of a lower and an upper indusium or of a cup-shaped indusium. As the first examples of this type, the sori of selected Hypolepidaceae and Dennstaedtiaceae are treated in detail. Regarding the phylogenetic relationships of the present families, the following conclusions can be drawn: (1) Owing to the meristem fusion of the indusia the sorus ofDennstaedtia possesses a new quality as compared to that of the Hypolepidaceae. Therefore, the Hypolepidaceae and the Dennstaedtiaceae should not be combined in a single family, as suggested by some authors. (2) The marginal position of the sori, and, in addition, the highly complex soral construction of the Dennstaedtiaceae, are not in support of the primitiveness of the two families, as sometimes assumed. (3) A sorus construction as found inDennstaedtia glauca can be gradually derived from a less elaborate one, such as that found, e.g., inPteridium. The continuous increase in the perfection of the soral construction (Pteridium → Dennstaedtia) suggests a placement of the Dennstaedtiaceae after the Hypolepidaceae. Springer-Verlag, 2000 Pteridophyta nationallicence Hypolepidaceae nationallicence Dennstaedtiaceae nationallicence Pteridium nationallicence Histiopteris nationallicence Hypolepis nationallicence Dennstaedtia nationallicence Construction morphology nationallicence leaf development nationallicence phase differentiation in leaf development nationallicence soral development nationallicence sorus nationallicence receptacle nationallicence indusium nationallicence basipetal marginal sorus nationallicence phylogeny nationallicence Plant Systematics and Evolution Springer-Verlag 220/3-4(2000-09-01), 161-183 0378-2697 220:3-4<161 2000 220 606 https://doi.org/10.1007/BF00985044 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00985044 text/html Onlinezugriff via DOI NATIONALLICENCE 100 1- Schölch Annette née Thorspecken, Langgewann 22, D-69121, Heidelberg, Federal Republic of Germany aut NATIONALLICENCE 773 0- Plant Systematics and Evolution Springer-Verlag 220/3-4(2000-09-01), 161-183 0378-2697 220:3-4<161 2000 220 606 Metadata rights reserved Springer special CC-BY-NC licence nationallicence SWISSBIB 47580712X BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer