The questionable affinities of Corsia (Corsiaceae): evidence from floral anatomy and pollen morphology

The floral anatomy and pollen morphology of Corsia are described in the context of its systematic relationships. Flowers of Corsia are epigynous, lack septal nectaries and possess a large labellum formed from the outer median tepal (sepal). The labellum is highly vascularized and has a prominent outgrowth (callus) that is apparently nectiiferous in some species of section Sessilis , although not in section Unguiculatis . The six fertile stamens are proximally fused to the style, forming a gynostemium. This combination of labellum and gynostemium is otherwise found only in Orchidaceae (Asparagales), but the orchid labellum is formed from the opposite median inner tepal, and is therefore not homologous with that of Corsia . The three genera of Corsiaceae ( Corsia , Arachnitis and Corsiopsis ) are markedly different in some respects; e.g. only Corsia has a gynostemium. However, they share a unique synapomorphy in the presence of a labellum formed from the outer median tepal (sepal). Corsia and Arachnitis are also similar in pollen sexine sculpturing. Among other putative relatives, the range of morphological similarities between Corsia and Campynemataceae (Liliales) tends to support recent preliminary inferences from molecular data that they are closely related, but a relationship with Thismia (Dioscoreales) cannot be discounted. Both Campynemataceae and Thismia share similarities with Corsia , including epigyny, absence of septal nectaries, presence of tepal nectaries, and pollen morphology. © 2002 Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 138 , 315–324.     

Leaf and stem anatomy of Vochysiaceae in relation to subfamilial and suprafamilial systematics

Several leaf anatomical features are potentially systematically informative within both the family Vochysiaceae and the order Myrtales, notably tracheoidal idioblasts, mucilage cells and secretory canals. Tracheoids with spiral wall thickenings are present in the mesophyll of most species of Vochysia , and also occur in several other families of Myrtales. Mucilage cells are common in the leaf epidermis in some Vochysiaceae. Secretory ducts are present in the midrib in Salvertia and Vochysia , which are apparently closely related, although Salvertia also shares some leaf anatomical characters with Qualea and Callisthene . Anatomical data do not support the segregation of Ruizterania from Qualea ; leaves of R. albiflora leaves are very similar to those of Q. paraensis in venation pattern, and leaf and stem anatomy. Different venation patterns are characteristic of sections within the genus Qualea , but within the large genus Vochysia , leaf anatomy is variable even within a subsection. Amongst other Myrtales, leaf anatomy of Vochysiaceae most closely resembles that of Combretaceae and Onagraceae. © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 138 , 339–364.     

What is the subtribe Glossonematinae (Apocynaceae: Asclepiadoideae)? A phylogenetic study based on cpDNA spacer

Evidence from the chloroplast trn T-L spacer, trn L intron and trn L-F spacer shows the subtribe Glossonematinae of the tribe Asclepiadeae, hitherto composed of the Arabian and North African genera Glossonema , Odontanthera and Solenostemma , not to be monophyletic. While the affinities of Solenostemma cannot be determined with certainty at present, molecular, karyological and morphological evidence suggests that Glossonema and Odontanthera are closely allied to Pentarrhinum , an African genus of five species, belonging to the Cynanchinae.  © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society , 2002, 139 , 145–158.     

Conservation genetics of an arctic species, Saxifraga rivularis L., in Britain

Genetic diversity in British populations of Saxifraga rivularis L. (Saxifragaceae) was assessed using isozymes, RAPDs, inter-SSRs and RFLPs of two non-coding chloroplast DNA regions. Low levels of variation were detected: only five molecular phenotypes were recovered, polymorphic for a single RAPD band and Pgd enzyme phenotype. The problem of drawing conservation recommendations from studies that show low levels of marker variation is discussed, and the importance of recognizing the limits of molecular genetic data in conservation biology is emphasized.     

Darwin on island plants

Islands played a key role in Charles Darwin's observations and experiments on plant dispersal. By means of these experiments, he expunged the old idea that a given species could originate at multiple times and in multiple places. More importantly, by seeing the capabilities for dispersal of plant seeds, fruits and branches, he was able to develop ideas of how plants reach islands and thus he is one of the founders of plant biogeography. For facts regarding floristic distribution of plants, Darwin relied on other workers, most notably Sir Joseph Dalton Hooker. Among his insights were the differences between oceanic and continental islands on a floristic basis, ideas on how age of island and distance from mainland areas influenced composition of island floras, the nature of endemism on islands and the role islands and archipelagos served as stepping stones in dispersal. Ingenious at proposing hypotheses, but always respectful of facts, Darwin sought explanations for plant adaptations on islands at a time when knowledge of island botany was little more than floristic in nature. These explanations are compared with selected recent works in island botany. © 2009 The Linnean Society of London, Botanical Journal of the Linnean Society, 2009, 161 , 20–25.     

Wood and stem anatomy of woody Amaranthaceae s.s.: ecology, systematics and the problems of defining rays in dicotyledons

Wood and stem anatomy is studied for seven species of six genera (root anatomy also reported for one species) of Amaranthaceae s.s. Quantitative data on vessels correlate closely with relative xeromorphy of respective species, agreeing with values reported for dicotyledons without successive cambia in comparable habitats. Libriform fibre abundance increases and vessel diameter decreases as stems and roots of the annual Amaranthus caudatus mature. Long, thick-walled fibres in Bosea yervamora may be related to the upright nature of elongate semi-climbing stems. Non-bordered or minutely bordered perforation plates characterize Amaranthaceae, as they do most other Caryophyllales. Amaranthaceae have idioblastic cells containing druses, rhomboidal crystals or crystal sand: these forms intergrade and seem closely related. Rays are present in secondary xylem of the Amaranthaceae studied. Cells intermediate between ray cells and libriform fibres occur in Charpentiera elliptica . Degrees of diversity in rays and reports of raylessness in Amaranthaceae induce discussion of definition and identification of rays in dicotyledons; some sources recognize both rays and radial plates of conjunctive tissue in Amaranthaceae. The action of successive cambia is described: lateral meristem periclinal divisions produce secondary cortex externally, conjunctive tissue internally and yield vascular cambia as well. Vascular cambia produce secondary phloem and secondary xylem, in both ray and fascicular zones, as in a dicotyledon with a single cambium. Identification of meristem activity and appreciation of varied ray manifestations are essential in understanding the ontogeny of stems in Amaranthaceae (which have recently been united with Chenopodiaceae).  © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society , 2003, 143 , 1–19.     

Three new species of Mitrephora (Annonaceae) from Sabah, Malaysia

Three new species of Mitrephora (Blume) Hook. f. & Thomson, M. clemensiorum, M. vittata and M. woodii , are described from Sabah, Malaysia. Mitrephora clemensiorum is related to M. korthalsiana Miq., but is distinguished by having long inflorescences, long flowering and fruiting pedicels, and fruits with sessile monocarps. Mitrephora vittata is related to M. reflexa Merr., but has lanceolate, subcoriaceous leaves, and densely pubescent inflorescence rachides, flowering pedicels and bracts. Mitrephora woodii is similar to M. heyneana (Hook. f. & Thomson) Thwaites, but has smaller flowers and fruits with sessile monocarps     

Gynoecium diversity and systematics in basal monocots

Gynoecium and ovule structure was comparatively studied in representatives of the basal monocots, including Acorales (Acoraceae), Alismatales (Araceae, Alismataceae, Aponogetonaceae, Butomaceae, Hydrocharitaceae, Junc‐aginaceae, Limnocharitaceae, Potamogetonaceae, Scheuchzeriaceae, Tofieldiaceae), Dioscoreales (Dioscoreaceae, Taccaceae), and Triuridaceae as a family of uncertain position in monocots. In all taxa studied the carpels or gynoecia are closed at anthesis. This closure is attained in different ways: (1) by secretion without postgenital fusion (Araceae, Hydrocharitaceae); (2) by partly postgenitally fused periphery but with a completely unfused canal (Alismataceae, Aponogetonaceae, Butomaceae, Limnocharitaceae, Scheuchzeriaceae, Dioscoreaceae, Taccaceae); (3) by completely postgenitally fused periphery but with an unfused canal in the centre (Acoraceae, Tofieldiaceae); (4) by complete postgenital fusion and without an (unfused) canal (Juncaginaceae, Potamogetonaceae). In many Alismatales (but without Araceae) carpels have two lateral lobes. The stigmatic surface is restricted to the uppermost part of the ventral slit (if the carpel is plicate); it is never distinctly double‐crested (Butomaceae?). Stigmas are commonly unicellular‐papillate and secretory in most taxa. The locules are filled with a (often) mucilaginous secretion in a number of taxa. Superficial (probably intrusive) ethereal oil cells were found in the carpel wall of Acorus gramineus (as in Piperales!). Idioblasts in carpels are otherwise rare. A number of basal monocots has orthotropous ovules, which is perhaps the plesiomorphic condition in the group. The presence of almost tenuinucellar (pseudocrassinucellar) ovules is relatively common (Acoraceae, many Araceae, some Alismatales s.s.), whereas completely tenuinucellar ovules are rare and do not characterize larger groups. However, crassinucellar ovules occur in the largest number of families among the study group (basal Araceae, many Alismatales s.s.) The outer integument is always annular in orthotropous ovules. The inner integument is often lobed and it mostly forms the micropyle, whereas the outer integument is always unlobed. Gynoecium structure supports the isolated position of Acoraceae as sister to all other monocots. However, in an overall view, if compared with all other families, Acoraceae clearly shows the greatest similarities with Araceae.     

A phylogenetic analysis of the monogenomic Triticeae (Poaceae) based on morphology

A cladistic analysis, primarily based on morphology, is presented from 40 diploid taxa representing the 24 monogenomic genera of the Triticeae. General problems related to the treatment of hybrids and supposedly allopolyploid heterogenomic taxa are highlighted. Special emphasis is given to taxa not traditionally included in Aegilops s.J. Most of the 33 characters used in the analysis are coded as binary. The only four multistate characters in the matrix are treated as unordered. Three diploid species of Bromus are used as outgroup. The number of equally parsimonious trees found is very large (approx. 170000; length = 107, ci = 0.36, ri = 0.75) and the strict consensus tree has an expectedly low level of resolution. However, most of the equally parsimonious trees owe their existence to an unresolved Aegilops clade. If this clade is replaced by its hypothetical ancestor, the number of equally parsimonious trees drops dramatically (48; length = 78, ci = 0.45, ri = 0.76). When trees for which more highly resolved compatible trees exist are excluded, only two trees remain. Bremer support is used as a measure of branch support. The trees based on morphology and on molecular data are largely incongruent.     

From forest to plantation? Obscure articles reveal alternative host plants for the coffee berry borer,Hypothenemus hampei (Coleoptera: Curculionidae)

The coffee berry borer, Hypothenemus hampei (Coleoptera: Curculionidae: Scolytinae), is the most devastating insect pest of coffee throughout the world. The insect is endemic to Africa but can now be found throughout nearly all coffee‐producing countries. One area of basic biology of the insect that remains unresolved is that of its alternative host plants, i.e. which fruits of plants, other than coffee, can the insect survive and reproduce in. An in‐depth survey of the literature revealed an article by Schedl listing 21 genera in 13 families in which the insect was collected, mainly in the Democratic Republic of Congo. This overlooked reference, together with information provided in other early articles, suggests that H. hampei is polyphagous, and could provide, if confirmed in the field, critical information on the evolution of this insect's diet, ecology and host range. © 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, ??, ??–??.