Our understanding of insect development and evolution has increased greatly due to recent advances in the comparative developmental approach. Modern developmental biology techniques such as in situ hybridization and molecular analysis of developmentally important genes and gene families have greatly facilitated these advances. The role of the comparative developmental approach in insect systematics is explored in this paper and we suggest two important applications of the approach to insect systematics--character dissection and morphological landmarking. Existing morphological characters can be dissected into their genetic and molecular components in some cases and this will lead to more and richer character information in systematic studies. Character landmarking will he essential to systematic studies for clarifying structures such as shapes or convergences, which are previously hard to analyze anatomical regions. Both approaches will aid greatly in expanding our understanding of homology in particular, and insect development in general.
-Phylogenetic tree derived from cladistic analyses of nuclear ribosomal DNA spacer sequences combined with morphological character matrix across the Amaryllidaceae tribe Amaryllideae (Meerow and Snijman 2001). Numbers above the lines are branch lengths. Numbers below the lines are bootstrap support percentages.
Results to date with various plastid genes confirmed the monophyly of the Amaryllidaceae s.s. as a whole, strongly supported the mostly African tribe Amaryllideae as sister to the rest of the family, and resolved geographically-based monophyletic groups, but failed to resolve the relationships among several basal lineages in the family (the African Haemantheae and Cyrtantheae, the Australasian Calostemmateae, and the American and Eurasian sister clades). We present analysis of plastid ndhF sequences that fully resolved the major clades of the family. The baccate-fruited Haemantheae and Calostemmateae are sister tribes, and the African endemic Cyrtantheae is sister to them both. This clade is sister to an American/Eurasian clade. We also present preliminary nuclear ribosomal ITS sequence analysis of the Eurasian clade. Lycorideae are basal in the group and begin a grade that continues with Hannonia, then Pancratium, then Lapiedra. The genera Galanthus, Narcissus, and Stembergia are resolved as monophyletic with strong support. Leucojum is paraphyletic and recognition of Acis for the mostly autumn-flowering Mediterranean species is supported. Recent phylogenetic analyses of various tribes and genera of the family are reviewed. Above the family level, Agapanthaceae, Alliaceae, and Amaryllidaceae form a well-supported monophyletic group, but exact resolution of the relationships among the three subclades varies depending on the sequence matrix utilized. The Angiosperm Phylogeny Group II has advocated combining all three into a single family, Alliaceae. We discuss this decision, which has historical precedent, but recommend that Amaryllidaceae be conserved as the name for the family in such a treatment.
Facsimile produced by microfilm-xerography. Thesis--Claremont Graduate School, 1972. Includes bibliographical references (leaves 179-184).
Thesis (M. A.)--Claremont Graduate School. "Literature cited" : leaves 119-125.
Thesis (M.A.)--Claremont Graduate School. Bibliography: leaves 54-55. Typewritten copy.
Xylem of roots and rhizomes of five species of four genera of tribe Cheilantheae (Pteridaceae; recently recognized by some as a segregate family, Cheilanthaceae) has been studied by means of scanning electron microscopy (SEM). All of these species occur in habitats (cliffs, talus) of mountains of North America that are seasonally dry in summer and cold in winter. The vessels prove diverse, indicating that different perforation plate modifications are represented in the cheilanthoid ferns of these habitats, rather than different degrees of the same kind of modification. The modifications include wide perforations alternating with narrow perforations (especially prominent in Bommeria); discontinuous perforation plates (Cheilanthes, Pellaea); and narrow, slitlike perforations (Cheilanthes). The discontinuous perforation plates are newly reported for ferns. The exceptionally prominent perforations of Bommeria vessels may be correlated with greater laminar surface and higher transpiration during wet periods in that genus; the other genera have small laminae with probable low transpiration rates even during moist periods.
Historical distributions of 31 tree species, chaparral, and coastal sage scrub described by Spanish land explorers in the late eighteenth and early nineteenth centuries (1769–1806) and in land grant diseños (1784–1846) are reconstructed at 634 localities across central and southern California. This baseline predates most formal botanical surveys by nearly a century, allowing for assessment of vegetation change over the broadest time frame for comparison with pre-historical evidences and future distributions. Spanish accounts are compared with historical sources in the Mexican era (1821–1848), American settlement (1848–1929), and modern range maps of the 1929–1934 Vegetation Type Map (VTM) survey. Among tree species that were recorded in Spanish explorations, the site-specific localities are consistent with VTM maps at the spatial resolution of the land expeditions. In contrast with massive deforestation across eastern North America since European colonization, hardwood and conifer forests in California sustained inconsequential cutting during Hispanic settlement. Spanish accounts and Mexican diseños occasionally provide remarkable detail of fine-scale distributions which have not changed over the past two centuries, including Pinus radiata forest at Cambria and Monterey, the eastern limit of Quercus lobata and Q. agrifolia woodlands with Aesculus californica in the Salinas Valley, as well as isolated stands of Cupressus macrocarpa and C. sargentii. Disjunct occurrences of trees in southern California were recorded at the same places they occur today, including an isolated grove of Q. engelmannii at the Baldwin Park Arboretum, and the Pinus coulteri stand in the mountains above Santa Barbara. The southern margin of mixed conifer forest in the San Bernardino Mountains has remained on the crest of the range since Garcés’ account in 1776. Long-term tree distributions are evaluated with respect to land use, grazing and climate change. We advocate the use of historical records as proxy data for climate change studies.
In the years 1960–1977, Rancho Santa Ana Botanic Garden fully embraces its role as teaching institution and as advocate and guardian of the native California flora. Expansion of the living collection, landscaping of the grounds, public education, herbarium and library activities, and publication output are detailed. To accommodate a growing number of graduate students, the faculty—consisting of Richard K. Benjamin, Sherwin Carlquist, and Lee. W. Lenz—is joined by Peter H. Raven, Ronald Scogin, John P. Simon, and Robert F. Thorne.
Justicia medrani and J. zopilotensis are described as new species while Anisacanthus gonzalezii is transferred into Justicia. The triad all have floral venation similar to red, tubular-flowered species of Justicia, though they differ from most Justicia in their tricolporate pollen with distinct pseudocolpi. In pollen and anther characters they are similar to Anisacanthus and Carlowrightia, but they differ from these in corolla vascularization and anther presentation and from Carlowrightia in corolla size. As the three taxa do not appear to represent a monophyletic group, and as Stearn has placed taxa with similar pollen into what has become a holding genus, Justicia, we include these in Justicia by default until further studies can decipher relationships within the genus.
Qualitative and quantitative wood features are reported for 38 species representing 22 genera, including the scandent genera Mendoncia and Thunbergia. Woods of Acanthaceae are characterized by relatively narrow vessels with simple perforation plates and alternate lateral wall pitting, septate libriform fibers, scanty vasicentric axial parenchyma, rays both multiseriate and uniseriate, erect ray cells abundant in rays (some species rayless or near-rayless), numerous small crystals or cystoliths in ray cells in a few genera (first documented reports of both characters in woods of Acanthaceae), and nonstoried structure. This constellation of features is very closely matched by woods of Gesneriaceae, Scrophulariaceae, Pedaliaceae, Martyniaceae, Bignoniaceae, and Myoporaceae (families listed in order ofdecreasing resemblance). Narrowness ofvessels in tropical Acanthaceae appears related to understory ecology. A few species in warm and seasonally dry areas have narrow, short vessel elements numerous per unit transection. Vasicentric tracheids occur in two nonscandent genera in dry areas. Vessel grouping is roughly proportional to dryness of habitat. Thunbergia alata, T. laurifolia, and all collections of Mendoncia have interxylary phloem (first report for Mendoncia). That feature, plus presence of occasional acicular crystals in rays and axial parenchyma and presence of large gelatinous fibers in phloem ally Mendoncia closely with Thunbergia, and Mendonciaceae is not justified for this and other reasons. Species of Thunbergia differ among themselves, and T. erecta and T. holstii resemble shrubby Acanthaceae more than they do Mendoncia in wood features. Thunbergia thus should not be segregated from Acanthaceae.
A taxonomic account of Acanthaceae subfamily Nelsonioideae based on morphological and phylogenetic data treats five genera with 172 species: Anisosepalum (3), Elytraria (21), Nelsonia (2), Saintpauliopsis (1), and Staurogyne (145). Two other currently recognized genera, Gynocraterium and Ophiorrhiziphyllon, are included within Staurogyne, and the new combinations, Staurogyne guianensis and S. macrobotrya, are proposed. Probable apomorphic and other diagnostic macro- and micromorphological characters are discussed relative to the subfamily and genera. Characters of the inflorescence, androecium (especially pollen), and seed show important phylogenetic and diagnostic signal. A key to genera, generic descriptions and discussions, illustrations, and distribution maps are provided. Lists of currently recognized species for each genus include synonymies and distributions by country.
Phoradendron is the largest genus of New World mistletoes, with about 250 species in two subgenera, Boreales and Aequatoriales, corresponding, respectively, to northern acataphyllous and southern cataphyllous groups. The typically acataphyllous P. californicum of western North America is controversial because recent phylogenetic work has nested it in the southern cataphyllous clade. Seedling establishment, stem anatomy, and endophytic system structure of this species were studied. Seedling haustorial holdfasts have gland cavities, structures considered absent in the Viscaceae clade of Santalales. The stem epidermis has a thick cuticle, deeply sunken stomata, and branched multicellular trichomes. The stem has an outer cortex of palisade chlorenchyma and an inner cortex of large isodiametric parenchyma cells. The boundary area between the outer and inner cortex contains druses and an unusual ring of small xylic bundles lacking protoxylem fibers and phloem. Sinkers are of two types: uniseriate, with only parenchyma that often has thick-walled transfer cells at its interface with vessels of the host; and multiseriate, with parenchyma and vessel elements that often are in direct contact and share simple perforation plates with vessels of the host. Sinker morphology is also dimorphic in the cataphyllous P. fragile but only unimorphic (multiseriate) in the acataphyllous P. juniperinum and P. serotinum. The dimorphic sinker system of P. californicum may be functionally partitioned, whereas these functions are combined in the unimorphic sinkers of other acataphyllous species. Differences in sinker morphology may reflect evolutionary trends in Phoradendron. This study also supports the hypothesis that P. californicum is more closely aligned with the mainly tropical cataphyllous species of the genus.
We have explored methods to achieve excellent results in study of the pollen grain wall by using only one electron microscope, the scanning electron microscope (SEM). While the secondary electron imaging mode, the most common in use, has great value in characterizing the exine surface it is possible to obtain a more comprehensive representation of pollen grain walls by expanding the capability of the secondary mode and making use of backscatter and transmission imaging detectors. In this way information is obtained about internal exine features that are likely to be more stable phylogenetically than the generally late-to-form surface structure. We illustrate the usefulness of natural and induced fractures, cryomicrotomy, thin-section examination, section deplasticization, localized acetolysis and pollen erosion by ionic bombardment in imaging exine structure. Techniques for expanding the use of SEM in taxonomic studies of mature pollen grain walls are outlined in flow chart sketches and illustrated with numerous examples from angiosperm pollen. -Authors
To understand evolutionary patterns and processes that account for anatomical diversity in relation to ecology and life form diversity, anatomy of storage roots and stems of the genus Adenia (Passifloraceae) were analyzed using an explicit phylogenetic context. Over 65,000 measurements are reported for 47 quantitative and qualitative traits from 58 species in the genus. Vestiges of lianous ancestry were apparent throughout the group, as treelets and lianous taxa alike share relatively short, often wide, vessel elements with simple, transverse perforation plates, and alternate lateral wall pitting; fibriform vessel elements, tracheids associated with vessels, and libriform fibers as additional tracheary elements; and well-developed axial parenchyma. Multiple cambial variants were observed, including anomalous parenchyma proliferation, anomalous vascular strands, successive cambia, and a novel type of intraxylary phloem. Successive cambia, trichomes, dermal features, and intraxylary phloem were synapomorphic for particular clades, whereas most traits were homoplastic. Several anatomical features of Adenia are consistent with xeromorphy. Repeated loss and gain of cuticularized, photosynthetic mature stems, narrow vessel elements, highly aggregated vessels, and other features indicative of xeromorphy reveal labile evolution of ecologically significant anatomical features, whereas features that are characteristic of the liana life form reveal evolutionary conservation despite diversification of life form within Adenia.
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J. Chris Pires
  • University of Missouri
Mark Chase
  • Royal Botanic Gardens, Kew
Michael F Fay
  • Royal Botanic Gardens, Kew
Marc Mcpherson
  • Evonik Corporation, USA
Thomas J Givnish
  • University of Wisconsin–Madison