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Pan-Spermatophyta P. D.Cantino and M. J. Donoghue in P.D. Cantino et al. (2007): 831 [P. D. Cantino , J. A. Doyle, and M. J. Donoghue], converted clade name Registration Number: 82 "progymnosperms" (a paraphyletic group) such as Aneurophyton, Tetraxylopteris, Archaeopteris, Definition: TI1e total clade of the crown clade and Cecropis (Beck, 1960), include a bifacial vas- !:Jpt.,.,natophyta. This is a crown-based total- cular cambium that produces both secondary clade definition. Abbreviated definition: total V xylem and secondary phloem and probably a cork of Spermatophyta. cambium that produces periderm (Scheckler and Banks, 1971). Kenrick and Crane (1997) listed Etymology: From the Greek pan- or pantos (all, three synapomorphies supporting inclusion the whole), indicating that the name refers to a of Pertica in this clade, but these are problem- total clade, and Spermatophyta (see entry in this atical. Synapomorphies proposed in their Table volume for etymology), the name of the corre- 4.6 were tetrastichous branching and presence sponding crown clade. of xylem rays (indicative of secondary xylem). However, tetrastichous branching is question- Reference Phylogeny: The primary reference able because it occurs in Tetraxylopteris but not phylogeny is Kenrick and Crane (1997: Fig. in other "progymnosperms," and branching in 7.10), where the clade Pan-Spermatophyta origi- Pertica is highly variable (Hotton et al., 2001). nates at the base of the branch leading to Pertica, Xylem rays and other anatomical characters are Tetraxylopteris, and seed plants. For more detailed actually unknown in Pertica, because its stems representation of the composition of Pan- are not preserved anatomically, and Kenrick and Spermatophyta (but no outgroups), see Hilton Crane (1997) correctly scored these characters as and Bateman (2006: Fig. 10). For a broader view unknown; their identification of rays as a syn- of outgroup relationships, see Kenrick and Crane apomorphy appears to be a result of using acc- (1997: Fig. 4.31), where Pan-Spermatophyta is the tran character optimization. However, secondary clade originating at the base of the branch that xylem with apparent rays has been described in a leads to Pertica and Tetraxylopteris (no extant possibly related fossil, Armoricaphyton (Gerrienne pan-spermatophytes are shown). and Gensel, 2016). In Table 7.2, Kenrick and Crane (1997) indicated that the clade includ- Composition: Spermatophyta (this volume) and ing Pertica, Tetraxylopteris, and seed plants, des- all extinct plants chat share more recent ances- ignated Radiatopses, is united by tetrastichous try with Spermatophyta than with any extant branching and "a distinctive form of procoxy- plants that do not bear seeds (e.g., Monilophyta, lem ontogeny with multiple strands occurring Lycopodiophyta). According to the reference phy- along the midplanes of the primary xylem ribs" logenies, stem spermatophytes chat lacked seeds ("radiate protoxylem" of Stein, 1993), but again include Tetr axylopteris, Archaeopteris, Cecropsis, and anatomical characters are unknown in Pertica, possibly Pertica;for stem spermatophytes that pos- and Armoricaphyton has a presumably more sessed seeds, see Apo-Spermatophyta (this volume). plesiomorphic Psilophyton-like centrarch stele with unlobed xylem (Gerrienne and Gensel, Diagnostic Apomorphies: Synapomorphies 2016). In any case, it is equivocal whether radi- of most Pan-Spermatophyta, including ate protoxylem is ancestral or derived within the Pan-Spermatophyta monilophyte-spermacophyte clade relative to the a phylogenetic nomenclature of Tracheophyta. ''permanent procoxylem" of early monilophytes. Taxon 56:822-846 and El-E44. Gerrienne, P., and P. G. Gensel. 2016. New data about anatomy, branching, and inferred Synonyms: The name Radiatopses (Kenrick and growth patterns in the Early Devonian plant Crane, 1997: Tables 7.1, 7.2) is an approximate Armoricaphyton chateaupannense, Montjean- synonym. It has a "synapomorphy-based defini- sur-Loire, France. Rev. Palaeobot. Palynol. tion," but its presumed composition may be iden- 224:38-53. tical to that of Pan-Spermatophyta if the latter Hilton, J., and R. M. Bateman. 2006. Pteridosperms includes Pertica. The name Progymnospermopsida, are the backbone of seed plant evolution. J proposed for relatives of seed plants that have Torrey Bot. Soc. 133:119-168. secondary xylem and phloem but lack seeds Hotton, C. L., F. M. Hueber, D. H. Griffing, and S. Bridge. 2001. (Beck, 1960), may be a partial and approximate J. Early terrestrial plant envi- ronments: An example from the Emsian of synonym in that it refers to a paraphyletic group Gaspe, Canada. Pp. 179-212 in Plants Invade that originated in approximately the same ances- the Land: Evolutionary and Environmental tor as Pan-Spermatophyta (see Comments). Perspectives (P. G. Gensel and D. Edwards, eds.). Columbia University Press, New York. Comments: Uncertainty about the status of Kenrick, P., and P. R. Crane. 1997. 1he Origin Progymnospermopsida and the corresponding · and Early Diversification of Land Plants-A informal name "progymnosperms" as (partial) Cladistic Study. Smithsonian Institution Press, synonyms of Pan-Spermatophyta is related to Washington, DC. the distinction between Pan-Spermatophyta Scheckler, S. E., and H. P. Banks. 1971. Anatomy and relationships of some Devonian pro- and Lignophyta, an apomorphy-based clade gymnosperms from New York. Am. J Bot. (Donoghue and Doyle in Cancino et al., 2007) 58:737-751. characterized by a bifacial vascular cambium that Stein, W. 1993. Modeling the evolution of stelar produces secondary xylem (wood) and phloem. architecture in vascular plants. Int. J Plant If a close relationship to seed plants is more crit- Sci. 154:229-263. ical to the concept of"progymnosperms" than is the possession of secondary xylem and phloem, Authors then the name "progymnosperms" is appropri- ately interpreted as a partial and approximate Philip D. Cancino; Department of Environmental synonym of Pan-Spermatophyta. However, if and Plant Biology; Ohio University; Athens, the possession of secondary xylem and phloem OH 45701, USA. Email: [email protected]. is more critical to the concept, then the name is James A. Doyle; Department of Evolution and Ecology; more appropriately interpreted as a partial and University of California; Davis, CA 95616, USA. Email: approximate synonym of Lignophyta. [email protected]. Michael J. Donoghue; Department of Ecology and Evolutionary Biology; Yale University; P.O. Literature Cited Box 208106; New Haven, CT 06520, USA. Email: [email protected]. Beck, C. B. 1960. The identity of Archaeopteris and Callixylon. Brittonia 12:351-368. Date Accepted: 31 January 2013; updated 09 Cantino, P. D., J. A. Doyle, S. W. Graham, W. February 2018 S. Judd, R. G. Olmstead, D. E. Soltis, P. S. Soltis, and M. Donoghue. J. 2007. Towards Primary Editor: Kevin de Queiroz 254 Apo-Spermatophyta P. D. Cantino and M. J. Donoghue in P. D. Cantino et al. (2007): 831 [P. D. Cantino, J. A. Doyle, and M. J. Donoghue), Converted clade name Registration Number: 14 includes the entire illustrated tree except the progymnosperms. See also Rothwell and Definition: The clade characterized by seeds Serbet (1994: Fig. 3). as inherited by Magnolia tripetala (Linnaeus) Linnaeus 1759 (Angiospermae), Podocarpus mac- Composition: The crown clade Spermatophyta rophylus (Thunberg) Sweet 1818 (Coniferae), (this volume) and all extinct seed-bearing plants Ginkgo biloba Linnaeus 1771, Cycas revoluta that lie outside the crown (eg., Palaeozoic Thunberg 1782 (Cycadophyta), and Gnetum seed ferns such as Elkinsia, Lyginopteris, and gnemon Linnaeus 1767 (Gnetophyta). This is Medullosa; for additional members, see Rothwel an apomorphy-based definition. A seed is a and Serbet, 1994; Hilton and Bateman, 2006). fertilized ovule, the ovule being an indehiscent megasporangium surrounded by an integu- Diagnostic Apomorphies: Ovules and seeds ment (represented by unfused or parcially fused (see Definition and Commentsfor more detailed integumentary lobes in the earliest members). descriptions). Some associated apomorphies are Presence of integument(s) (fused or unfused) listed under Comments. and megasporangium indehiscence are fully correlated in all known seed plants, with the Synonyms: The name Spermatophtata Kenrick exception of some parasitic angiosperms (e.g., and Crane (1997: Table 7.2) is an unambiguous derived Brown et in which It is Santalales; al., 2010) synonym. defined based on two apomor- the integuments have been lost. If only one of phies-presence of an integument and only one the two features is present, the presence of an functional megaspore-both of which charac- integument rather than indehiscence will deter- terize the ovule and the former of which we have mine whether a structure is an ovule accord- used as the defining feature ofan ovule for the pur- ing to the definition used here. Abbreviated pose of our definition (see Comments). The name definition: V apo seeds [Magnolia ripetala Spermatophyta as used by many earlier authors is Linnaeus & macro- also (Linnaeus) 1759 Podocarpus implicitly apomorphy-based, but we prefer phylus (Thunberg) Sweet 1818 && Ginkgobilob to use it for the crown clade (see Spermatophyta, Linnaeus 1771 & Cycas revoluta Thunberg 1782 this volume). The name as used & Gymnospermae, Gnetum gnemon Linnaeus 1767J. for living and fossil seed plants other than angio- sperms, is a partial synonym; gymnosperms Etymology: From the Greek ap0-, indicating originated from the same