On the Morphology and Relationships on the Taxaceae

Florin, Rudolf

doi:10.1086/335515

Cited by 67 publications

(39 citation statements)

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“…It should be stressed that nr18S rRNA sequences are too conserved to resolve relationships among these two close families and that Stefanovic et al used a relatively short length of the nr28S sequences (683 bp). The phylogenetic analyses presented here confirm the inferences of the morphological studies of Hart (1987) and Price (1990) but refute the claims of Florin (1948Florin ( , 1954 and Singh (1961) that Cephalotaxaceae has no alliance with Taxaceae.…”

Section: Relationships Of Taxaceae To Other Gymnospermssupporting

confidence: 85%

“…In most other conifers the ovules are borne axillary on cone scales (Hart, 1987;Price, 1990;Chaw et al, 1993, and references therein). Because of this distinction, the yew family was historically excluded from the Coniferales, notably by Sahni (1920) and Florin (1948Florin ( , 1951, and was placed in its own order, Taxales. However, proembryogeny (Doyle, 1963;Singh, 1978;Dogra, 1980), chemical (Heagnauer, 1988), morphological (Hart, 1987), and molecular (Raubeson and Jansen, 1992;Chase et al, 1993;Chaw et al, 1997;Stefanovic et al, 1998) data accumulated later did not provide evidence favoring Sahni or Florin's treatment. Due to the efficacy of taxane compounds in anticancer therapies, taxads have been experiencing a research renaissance.…”

Section: Introductionmentioning

confidence: 99%

“…The fossil record of Cephalotaxus is very limited, and its ancestry is still unclear (Miller, 1977). Florin (1948Florin ( , 1954 considered the Cephalotaxceae as having no alliance with Taxaceae. This opinion was further defended by Singh (1961), who claimed that similarities between the two families, such as spiral thickening in the xylem tracheids, unwinged pollen grains without prothallial cells, and embryogeny, were also found in other conifer families.…”

Section: Introductionmentioning

confidence: 99%

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Phylogeny of Taxaceae and Cephalotaxaceae Genera Inferred from Chloroplast matK Gene and Nuclear rDNA ITS Region

Cheng

Nicolson

Tripp

et al. 2000

Molecular Phylogenetics and Evolution

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Section: Relationships Of Taxaceae To Other Gymnospermssupporting

confidence: 85%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Phylogeny of Taxaceae and Cephalotaxaceae Genera Inferred from Chloroplast matK Gene and Nuclear rDNA ITS Region

Cheng

Nicolson

Tripp

et al. 2000

Molecular Phylogenetics and Evolution

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“…Nevertheless, Buchholz's classification was subsequently adopted by Chamberlain (1935), Janchen (1949), Li (1953), Keng (1975Keng ( , 1977, and many others. Florin (1948Florin ( , 1954, largely following Sahni, strongly argued that the terminal position of the uniovulate seed of Taxaceae constitutes a primitive character and that its origin is entirely different from that of the conifers that stem from the Cordaitales. He suggested excluding Taxaceae from the Coniferales and forming a class; this view was accepted by Sporne (1965, as an order), Stewart (1983, as an order), and Bold et al (1987, as a class).…”

Section: Introductionmentioning

confidence: 99%

The phylogenetic position of taxaceae based on 18S rRNA sequences

et al. 1993

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The evolutionary position of the yew family, Taxaceae, has been very controversial. Some plant taxonomists strongly advocate excluding Taxaceae from the conifer order and raising its taxonomic status to a new order or even class because of its absence of seed cones, contrary to the case in the majority of conifers. However, other authors believe that the Taxaceae are not fundamentally different from the rest of the conifers except in that they possess the most reduced solitary-ovule cones. To resolve the controversy, we have sequenced the 18S rRNA genes from representative gymnosperms: Taxus mairei (Taxaceae), Podocarpus nakaii (Podocarpaceae), Pinus luchuensis (Pinaceae), and Ginkgo biloba (Ginkgoales). Our phylogenetic analysis of the new sequence data with the published 18S rRNA sequence of Zamia pumila (a.cycad) as an outgroup strongly indicates that Taxus, Pinus, and Podocarpus form a monophyletic group with the exclusion of Ginkgo and that Taxus is more closely related to Pinus than to Podocarpus. Therefore, Taxaceae should be classified as a family of Coniferales. Our finding that Taxaceae, Pinaceae, and Podocarpaceae form a clade contradicts both the view that the uniovulate seed of Taxaceae is a primitive character and the view that the Taxaceae are descendants of the Podocarpaceae. Rather, the uniovulate seed of Taxaceae and that of some species of Podocarpus appear to have different origins, probably all reduced from multiovulate cones.

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“…The staminate strobilus in Taxus has been interpreted as both primitive and derived. In fact, the radially arranged microsporangia and non-saccate pollen were used as reasons to exclude Taxaceae from Coniferales (Florin, 1948). The staminate strobilus in Taxus may be an intermediate form between the radially symmetric microsporophylls in Cordaitales and Ginkgoales and the dorsiventrally¯attened microsporophylls in the majority of conifers (Takhtajan, 1953).…”

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confidence: 99%