The systematic relationships of glucosinolate-producing plants and related families: a cladistic investigation based on morphological and molecular characters

A cladistic analysis is performed using 94 morphological and biochemical characters for 42 genera to compare a phylogeny based on morphological data with those obtained using different genes ( rbc L, atp B, 18S RNA, mat K) or their combination with morphological data, and to understand the floral evolution within the expanded Brassicales (Capparales) relative to Sapindales and Malvales. The tree produced with morphological data is congruent with those obtained from macromolecular studies in obtaining a well-supported glucosinolate-producing clade and an expanded Sapindales. The combined analysis of the morphological and molecular characters is generally well resolved with support for many of the relationships. The inclusion of the fossil taxon Dressiantha demonstrates the value of inserting fossil evidence in phylogenetic analyses. However, the fossil appears to be related to the Anacardiaceae and not to the Brassicales. The core Brassicales are well supported by a number of synapomorphies, although the internal position of Tovariaceae and Pentadiplandraceae is not well resolved. Emblingiaceae appears to be related to Bataceae and Salvadoraceae. Several significant morphological characters are mapped on the combined trees and their evolutionary significance is discussed. Within Brassicales and Sapindales several well supported clades can be recognized which merit ordinal or subordinal status, putting the present orders at a higher level; these include: Tropaeolales, Setchellanthales, Batidales, Brassicales (Brassiciflorae), Burserales, Sapindales and Rutales (Sapindiflorae). The present scheme of affinities within the Brassicales corresponds well with a gradual morphological evolution in the order.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 151 , 453–494.     

The uniqueness of palms

Palms build tall trees entirely by primary growth in a way that limits their growth habit, but not their capacity for continued stem development. They achieve massive primary stature because of distinctive features of leaf development, stem vasculature and anatomical properties. They exhibit several record features of leaf and seed, and inflorescence size and leaves of great complexity. A marked ability to generate new roots allows them to be transplanted easily. As climbing plants they develop the longest unrooted stems in which there are, paradoxically, anomalous features of vascular construction compared with tree palms. It is here claimed that they are the world's longest lived trees because stem cells of several kinds remain active in differentiated tissues throughout the life of the palm. Absence of physiological dormancy may be related to this property, together with inability to withstand freezing temperatures that would cause irreversible cavitation of tracheary elements. This largely restricts them to the tropics, for which they are emblematic organisms. In these biological features palms are indeed unique organisms.  © 2006 The Linnean Society of London, Botanical Journal of the Linnean Society , 2006, 151 , 5–14.     

The stomatal apparatus of Lycopodium japonicum and its bearing on the stomata of the Devonian lycophyte Drepanophycus spinaeformis

The structure of the stomatal apparatus of the leaf of Lycopodium japonicum Thumb was studied using epidermal macerations, sections and scanning electron microscopy. The stomatal apparatus of L. japonicum consists of two large guard cells and pore, and is anomocytic. Based on light microscopy, the impression from epidermal macerations that there were two small guard cells surrounded by two, large, similarly shaped, subsidiary cells (paracytic) derives from a pronounced elliptical cuticular ledge on the surface of the guard cells surrounding a thickened circumporal area. A similar appearance is characteristic of cuticle preparations of the Devonian lycophyte Drepanophycus spinaeformis Göppert. We therefore conclude, as did W.H. Lang over 70 years ago, that the stomata of the early lycophyte were also anomocytic, as were those of a second species of Drepanophycus , D. qujingensis Li & Edwards.  © 2005 The Linnean Society of London, Botanical Journal of the Linnean Society , 2005, 149 , 209–216.     

Comparative floral structure and systematics in Cucurbitales (Corynocarpaceae, Coriariaceae, Tetramelaceae, Datiscaceae, Begoniaceae, Cucurbitaceae, Anisophylleaceae)

Floral structure, including morphology, anatomy and histology, was comparatively studied in representatives of all seven families of Cucurbitales as currently circumscribed by other authors based on molecular analyses and including Corynocarpaceae, Coriariaceae, Tetramelaceae, Datiscaceae, Begoniaceae, Cucurbitaceae and Anisophylleaceae. Three superfamilial clades are supported by floral structure: Tetramelaceae/Datiscaceae, Tetramelaceae/Datiscaceae/Begoniaceae and Corynocarpaceae/Coriariaceae. Anisophylleaceae appear most isolated in Cucurbitales, and show more similarities with Oxalidales, especially Cunoniaceae, although some features of interest are shared with other Cucurbitales and not Oxalidales. Tetramelaceae and Datiscaceae share dioecy, completely isomerous (but not regularly pentamerous) flowers (not in male Datiscaceae), only small sepals, lacking petals (not in male Octomeles). Tetramelaceae, Datiscaceae and Begoniaceae share the presence of numerous small ovules and seeds with a large‐celled surface, 2‐cell‐layered integuments, and a collar around the funicle by an extension of the outer integument. Corynocarpaceae and Coriariaceae share thick petals, unifacial stigmas, superior ovaries with a single, median, pendant syntropous ovule per carpel, and annular outer integuments with vasculature at the base. The four classical core families of Cucurbitales: Tetramelaceae, Datiscaceae, Begoniaceae and Cucurbitaceae (relationship unresolved, not retrieved as a clade as yet in molecular studies) share in various combinations androdioecy, basifixed and extrorse or latrorse anthers, trimerous gynoecia, bifurcate free carpel parts, an extended roof over the ovary formed by the ventral parts of the carpels, and parietal placentae. Trends of interest at the order level are unisexual flowers, thick, pointed petals (if present) that do not conform to the model in other rosids or basal core eudicots, a 2‐cell‐layered inner integument, which is delayed in development, and lacking or scant tanniferous tissues in flowers. © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society, 2004, 145 , 129–185.     

Supraspecific taxa as terminals in cladistic analysis: implicit assumptions of monophyly and a comparison of methods

The use of supraspecific terminal taxa to represent groups of species in phylogenetic analyses can result in changes to inferred relationships as compared to a complete species level analysis. These changes in topology result from interactions among (1) the cladistic status of the supraspecific taxa; (2) the method used to represent the taxa as single terminals, and (3) incongruence in the data set. We examine the effects of using supraspecific terminal taxa using a parallel analysis of hypothetical examples and an actual data matrix for the true seals (Mammalia: Phocidae). Incongruence among characters can produce changes in topology by shifting the ‘balance of power’ among groups of characters when supraspecific taxa are represented as single terminals. In the absence of homoplasy, the correct topology is maintained. Of the three methods for representing supraspecific taxa, the ‘ancestral’ method, which explicidy infers the common ancestor of the group corresponding to the taxon, performed the best, always maintaining the correct topology when monophyletic taxa were represented. This agrees with theoretical predictions. The ‘democratic’ and ‘exemplar’ methods, which represent the higher level taxon through a survey of all or one of its extant constituent species, respectively, were not as effective in maintaining the correct topology. Although both occasionally provided correct answers, their occurrences were largely unpredictable. The success of the exemplar method varies with the species selected. The simultaneous representation of two or more higher level taxa produced interactive effects where the resultant topology included different clades than when the taxa were collapsed individually. Interactive effects occurred with all three methods, albeit to a lesser degree for the ancestral method. Changes in topology were observed regardless of whether the higher group was monophyletic or not, but were more prevalent when it was paraphyletic. Unfortunately, there does not seem to be a reliable way to determine when a paraphyletic group has been included in the analysis (e.g. through bootstrap values or indices measuring homoplasy). The implications of these findings for phylogenetic analyses of molecular data are also discussed.     

The middle ear of the skull of birds: the ostrich, Struthio camelus L.

The morphology of the middle ear region including die basicranium and quadrate of Strulhxo is very simil.n to ilic same region in the orders Procellariiformes, Pelecaniformes, Ciconiiformes and Sphenisciformes. Struthio though, has some unique middle ear characters such as die lack of a chorda tympani nerve, the arrangement of die glossopharyngeal and vagus nerve foramina, die structure in the upper neck of die external ophthalmic vein and die position of die Eustachian tube. The articulatory surfaces for the quadrate bom on die zygomatic process of the squamosal and the mandible are unique in Struthio when compared to the several orders mentioned above.