Foonchewia guangdongensis gen. et sp. nov. (Rubioideae: Rubiaceae) and its systematic position inferred from chloroplast sequences and morphology

Abstract The new species, Foonchewia guangdongensis R. J. Wang & H. Z. Wen and the new monotypic genus Foonchewia R. J. Wang (Rubioideae, Rubiaceae), are described from eastern Guangdong, China. It is characterized by its subshrub habit, pentamerous and heterostylous flowers, 2‐1ocular ovary with many ovules, and apically dehiscent capsules with numerous angulated seeds. Phylogenetic analysis of four chloroplast DNA regions (rbcL, rps16, ndhF, and atpB‐rbcL) revealed that the new genus is nested in the Spermacoceae alliance and is sister to Dunnia. Morphological comparison between these two genera indicated that they had few synapomorphies; it was therefore inappropriate to classify the new genus in the existing tribe Dunnieae, and a new tribe, Foonchewieae R. J. Wang, is accordingly proposed.     

Structure,ultrastructure and evolution of floral nectaries in the twinflower tribe Linnaeeae and related taxa (Caprifoliaceae)

Linnaeeae is a small tribe of Caprifoliaceae consisting of six genera and c. 20 species. In Linnaeeae, floral nectaries are located on the corolla‐filament‐tube and nectar is produced from unicellular glandular hairs. We studied 23 taxa using scanning electron microscopy (SEM), light microscopy (LM) and transmission electron microscopy (TEM) and found two distinct nectary morphologies, zonate and gibbous types, and two distinct types of glandular hair, clavate and smooth base types. Plesiomorphic characters associated with the nectary and identified in the tribe include hypocrateriform corollas, dichogamous flowers, zonate nectaries, wet papillate stigmas, vestigial nectary disc and smooth pollen grains. Apomorphic characters include bilabiate corollas, homogamous flowers, bulging nectaries, dry papillate stigmas and echinulate pollen grains. The nectary structure is similar in Vesalea and Linnaea and differs from the rest of the tribe, in accordance with recent phylogenetic results. Nectar secretion is typically granulocrine with subcuticular accumulation of nectar, which we compared with the secretion in multicellular hairs of Adoxa moschatellina. The cuticle on the hair becomes detached from the cell wall and large subcuticular spaces filled with nectar are formed. Nectar is probably released in areas with a thin cuticle. In Zabelia, the smooth basal part of the hair could help to build up the hydrostatic pressure.     

Testing the monophyly and position of the North American shrubby desert genus Leucophyllum (Scrophulariaceae: Leucophylleae)

Leucophyllum is one of the most remarkable endemic genera of North American deserts, with its simultaneous bloom of showy purple flowers. With Eremogeton and probably Capraria it forms part of tribe Leucophylleae. Leucophyllum has 16 species distributed mostly throughout the Chihuahuan and Tehuacán deserts. The three genera were sampled to investigate the phylogenetic relationships among them and to test the monophyly of Leucophyllum, based on plastid DNA (trnL‐F, rps16) and nuclear ribosomal (nr)DNA (internal transcribed spacer) sequences. Bayesian inference and maximum‐likelihood analyses confirmed that tribe Leucophylleae is monophyletic and formed by the three Neotropical genera. Separate (plastid DNA and nrDNA) and combined analyses retrieved Leucophyllum as paraphyletic, with L. mojinense as the sister species to the rest of the species in the tribe and Capraria spp. nested in one of two clades of Leucophyllum. Further monographic work is needed to identify the defining characters and limits of the genera, but we suggest that L. mojinense, with its different vegetative architecture, distinctive flowers and dissimilar distribution could be placed in its own genus. Each of the two clades in Leucophyllum could be considered a genus in its own right, and Capraria and Eremogeton can be recognized as independent genera, as they are at present. Leucophyllum ambiguum, the type species of the genus, belongs to one of the clades so the species of the other could be considered members of a new genus. The only diagnostic character detected at present is a ventricose corolla tube in one of the clades in Leucophyllum and a pressed corolla tube in the other. © 2013 The Linnean Society of London     

Trichome anatomy of the Saxifragaceae S. l.from the southern hemisphere

Trichome anatomy was examined by light and scanning electron microscopy in 25 genera of Engler's Saxifragaceae from the southern hemisphere. Four principal categories of trichome were recognized: (1) multiseriate with a glandular head; (2) uniseriate with a glandular head; (3) uniseriate, eglandular; (4) unicellular, eglandular. The shape of eglandular hairs ranges from erect to sickle-shaped to T-shaped. The main taxonomic conclusions are as follows: (a) Vahlia should be excluded from tribe Saxifrageae and a possible relationship with Montinia investigated; (b) Francoa and Tetilta (tribe Francoeae) are closely related, although the relationship of the tribe to its parent subfamily, Saxifragoideae, is unclear; (c) Eremosyne is probably allied to the Escallonioideae; (d) subfamily Brexioideae is heterogeneous in trichome anatomy, but the relationships of its constituent genera remain problematic; (e) subfamily Escallonioideae is heterogeneous in trichome anatomy, although similarities between and within the constituent tribes do exist. Thus Cuttsia and Abrophyllum form a natural group (tribe Cuttsieae), to which Carpodetus (tribe Argophylleae) may also be related; similarity in trichome anatomy between Argophyttum and Corokia (tribe Argophylleae) is substantiated by an extensive survey of all the species, and the data tentatively suggest a possible hydrangeoid affinity for these two genera.Forgesia (tribe Forgesieae) is shown to possess the same kind of hairs in the flowers as Quintinia (tribe Escallonieae), and Choristylis (tribe Forgesieae) is shown to be remarkably similar to Escallonia, prompting a suggestion that the two tribes be merged. Trichome data support the inclusion of Anopterus and Polyosma in their own tribes, although their wider affinities remain unclear. Doubts about the inclusion of the glabrous Tribeles in Escallonioideae are expressed. Our material of the following additional genera Lepuropetalon, Tetracarpaea and Brexia was glabrous and little comment could be made about them.     

SYSTEMATIC ANATOMY OF THE FLOWER AND FRUIT OF COROKIA

Corokia, a genus of shrubs of New Zealand, eastern Australia, and certain Pacific islands, was first placed in Rhamnaceae, later in Cornaceae, and most recently next to Argophyllum, subfamily Escallonioideae, in Engler's monograph of the Saxifragaceae. Most manuals still list Corokia under Cornaceae from which it is readily excluded by several characters, including pluricellular T-shaped trichomes, ligulate petals, vascular bundles running longitudinally through the center of the inferior gynoecium, histology and germination of the woody endocarp, and a conspicuous subepidermal layer of tannin-containing cells. Corokia collenettei, endemic to the isolated island Rapa, retains the most primitive floral characters of the genus. Anatomical comparison of Corokia flowers with flowers of Argophyllum shows similarities that probably indicate affinity, but the relation of these two genera to others in Engler's subfamily Escallonioideae is unclear. Engler's inclusion of Berenice and Carpodetus with Corokia and Argophyllum in a tribe Argophylleae seems especially artificial.     

RESURRECTION OF THE GENUS ENDOLEPIS AND CLARIFICATION OF ATRIPLEX PHYLLOSTEGIA (CHENOPODIACEAE)

The genus Endolepis was first described by Torrey in 1860 with E. suckleyi (E. dioica [Nutt.] Standley) as the only species, noting that it differed from species of Atriplex by the presence of perianth parts in the female flowers. Later, Standley described two additional species: E. covillei and E. monilifera. H. M. Hall and Clements merged Endolepis with Atriplex because they thought that the presence of perianth parts in female flowers was variable in Atriplex phyllostegia. It is now clear that this observation was erroneous; A. phyllostegia never has perianth parts in its female flowers. The plants that they examined that had female flowers with perianth parts were specimens of Endolepis covillei; only those with female flowers devoid of perianth parts were specimens of Atriplex phyllostegia. These two taxa differ by several other major attributes including differences in leaf shape, leaf anatomy, fruiting-bract size and shape, fruiting-bract appendages, and flowering habit, and therefore justify taxonomic separation. Also, because the presence of perianth parts in bracteolate female flowers is a rare attribute in the tribe Atripliceae, consistently absent in Atriplex, but always present in Endolepis, the retention of the genus Endolepis, separate from Atriplex, is deemed warranted. We propose that the genus Endolepis comprise two species, E. dioica and E. covillei. The species named E. monilifera by Standley is based on a specimen of Atriplex serenana Nels.     

A new species of Dolichoura (Melastomataceae) and broadened circumscription of the genus

Dolichoura has two species, D. spiritusanctensis and D. kollmannii, the latter described here. The genus can be recognized within the tribe Merianieae by 6-or 7-merous flowers, purple petals, stamens with a dorsal, spiraled appendage at the base of the connective, and seeds with narrow, lateral wings. The new species can be recognized by the suffruticose habit, 4-winged branches, coriaceous leaves with very small petioles and bullate adaxial surfaces, and by the 6-merous flowers.     

Phylogeny and morphological evolution of tribe Menispermeae (Menispermaceae) inferred from chloroplast and nuclear sequences

The Menispermaceae family contains ca. 72 genera with 450 species that are almost entirely tropical. Its phylogeny at the tribal level has never been examined using molecular data. Here we used DNA sequences of the chloroplast matK gene and trnL-F regions, and the nuclear ITS region to study the delimitation and position of the tribe Menispermeae within the family and its subtribal monophyletic groups. Family-wide phylogenetic analyses of the chloroplast data produced two strongly supported clades. The first clade contains two subclades: Coscinieae including Arcangelisia and Anamirta, and Tinosporeae sensu lato including Fibraureae, supported by morphological characters, such as traits of the cotyledon, stylar scar and embryo. The second clade consists of the tribes Menispermeae sensu DC. and Tiliacoreae Miers. All our analyses surprisingly recognized that tribe Menispermeae is not monophyletic unless tribe Tiliacoreae is included, suggesting that characters of cotyledon and stylar scar are very important for the infrafamilial classification, and that endosperm presence vs. absence was over-emphasized in traditionally tribal division of the family. Our topologies indicate a secondary loss of endosperm. The monophyly of two subtribes of the tribe Menispermeae, Stephaniinae and Cissampelinae, is supported by the cpDNA and ITS data, as well as by morphological characters, including aperture types and shapes, and colpal membrane features of pollen grains, and sepal number of male flowers. The Cocculinae was recognized as a paraphyletic group containing the remaining genera of the tribe Menispermeae.     

THE DEVELOPMENTAL BASIS FOR SEXUAL EXPRESSION IN CERATONIA SILIQUA (LEGUMINOSAE: CAESALPINIOIDEAE: CASSIEAE)

The flowers of Ceratonia siliqua, an anomalous caesalpinioid legume in the tribe Cassieae, are unusual in being unisexual and in lacking petals. Inflorescence development, organogeny, and flower development are described for this species. All flowers are originally bisexual, but one sex is suppressed during late development of functionally male and female flowers. Ceratonia siliqua is highly plastic in sexuality of individuals, inflorescence branching pattern, racemose or cymose inflorescences, bracteole presence, terminal flower presence, organ number per whorl, missing floral organs, pollen grain form, and carpel cleft orientation. Order of initiation is: five sepals in helical order, then five stamens in helical order together with the carpel. Each stamen is initiated as two alternisepalous primordia that fuse to become a continuous antesepalous ridge; in some flowers, the last one or two stamens of the five may form as individual antesepalous mounds. Petal rudiments are occasional in mature flowers. Position of organs is atypical: the median sepal is on the adaxial side in Ceratonia, rather than abaxial as in most other caesalpinioids. This feature in Ceratonia may be viewed as a link to subfamily Mimosoideae, in which this character state is constant.     

Pollination systems in Pogonieae (Orchidaceae: Vanilloideae): A hypothesis of evolution among reward and rewardless flowers

The tribe Pogonieae of Vanilloideae (Orchidaceae) consists of six genera, including Pogoniopsis, a myco-heterotrophic taxon with morphological characteristics distinct from the remaining of the tribe. A hypothesis about the phylogeny of the tribe was inferred, involving all currently recognized genera, based on isolated and combined sequence data of 5.8S, 18S and 26S (nrDNA) regions using parsimony and Bayesian analyses. Phylogenetic analyses show that inclusion of Pogoniopsis turns the tribe Pogonieae paraphyletic. All analyses reveal that Pogoniopsis is closely related to members of Epidendroideae. The pantropical Vanilla is monophyletic if Dictyophyllaria is assumed as synonym of Vanilla. Members of Pogonieae are pollinated by several groups of solitary and social bees, two pollination systems being recognized: reward-producing and deceptive. The molecular phylogeny suggests that ancestrals related to Pogonieae gave rise to two evolutionary lines: a tropical one with reward production of flowers, and a predominantly temperate regions invading line with deceptive flowers. Reward-producing flowers characterize the South and Central American clade (=Cleistes), while deceptive pollination is prominent in the clade that includes North American-Asiatic taxa plus the Amazonian genus Duckeella.     

Floral anatomy,embryology, seed,and fruit development in Cephalanthus (Naucleeae-Rubiaceae), with emphasis on C. glabratus

Information on the reproductive anatomy in genera of the tribe Naucleeae, particularly Cephalanthus, is scarce and fragmented. Of the six species in the genus, only the mature megagamethophyte of Cephalanthus occidentalis has been described. This study aims to provide information on embryological aspects in flowers of C. glabratus and to analyze the morphology and anatomy of the flowers, fruit, and seed in the six species of the genus. Cephalanthus glabratus have imperfect flowers: pistillate (PF) and staminate (SF). In the PF, the ovules are functional, while in the SF, they atrophy during the formation of the embryo sac. The mature ovule has a single integument, corresponds to the Phyllis type and the embryo sac is a Polygonum type, forming only in the PF. The presence of pollenkitt and secondary presentation of pollen were observed in the SF, as well as in the pollen formation previously described, whereas in the PF, they are absent, due to the collapse of the pollen grains inside the indehiscent anthers. The analysis of the ontogeny of the ovular excrescence in C. glabratus determined its funicular origin, calling it an aril. Its development is a pre-anthesis event, initiated during megasporogenesis. In seeds, the aril is a fleshy, white appendage which almost completely envelops the seeds of Cephalanthus, except for Cephalanthus natalensis where it is noticeably more reduced. Studies of the fruit in Cephalanthus species indicate that the infructescence is a dry schizocarp which separates into uni-seminated mericarps, except in C. natalensis that has fleshy indehiscent fruit.

     

POLYACETYLENE RESERVOIR (DUCT) DEVELOPMENT IN AMBROSIA TRIFIDA (ASTERACEAE) STAMINATE FLOWERS

Mature staminate flowers of giant ragweed (Ambrosia trifida L.; Asteraceae, tribe Heliantheae) are about 2 mm long. Each of the five fused petals is traversed for most of its length by a prominent polyacetylene-filled reservoir (PAR). PAR'S have a biseriate epithelium and, except for their short length of about 1.5 mm, seem identical to the much longer PAR's of leaf and stem. Study of sections of resin-embedded flowers at different developmental stages showed that corolla PAR's appear with a full complement of epithelial cells, and occupy their full relative length, in flowers only 150 μm in length. As the flower enlarges, the original epithelial cells also enlarge and elongate, and secrete into the lumen, which opens simultaneously for its entire length when the flower is nearly 300 μm long. PAR's in mature flowers have only their original epithelial cells, which remain alive. Corolla PAR's seem anatomically to be representative of the canals and ducts that have been described elsewhere in Asteraceae.     

Floral structure and development in the monoecious palm Gaussia attenuata (Arecaceae; Arecoideae)

Background and Aims

Sexual dimorphism, at both the flower and plant level, is widespread in the palm family (Arecaceae), in contrast to the situation in angiosperms as a whole. The tribe Chamaedoreeae is of special interest for studies of the evolution of sexual expression since dioecy appears to have evolved independently twice in this group from a monoecious ancestor. In order to understand the underlying evolutionary pathways, it is important to obtain detailed information on flower structure and development in each of the main clades.

Methods

Dissection and light and scanning electron microscopy were performed on developing flowers of Gaussia attenuata, a neotropical species belonging to one of the three monoecious genera of the tribe.

Key Results

Like species of the other monoecious genera of the Chamaedoreeae (namely Hyophorbe and Synechanthus), G. attenuata produces a bisexual flower cluster known as an acervulus, consisting of a row of male flowers with a basal female flower. Whereas the sterile androecium of female flowers terminated its development at an early stage of floral ontogeny, the pistillode of male flowers was large in size but with no recognizable ovule, developing for a longer period of time. Conspicuous nectary differentiation in the pistillode suggested a possible role in pollinator attraction.

Conclusions

Gaussia attenuata displays a number of floral characters that are likely to be ancestral to the tribe, notably the acervulus flower cluster, which is conserved in the other monoecious genera and also (albeit in a unisexual male form) in the dioecious genera (Wendlandiella and a few species of Chamaedorea). Comparison with earlier data from other genera suggests that large nectariferous pistillodes and early arrest in staminode development might also be regarded as ancestral characters in this tribe.     

Evolution of flower shape inVeroniceae (Scrophulariaceae)

Floral evolution in the tribeVeroniceae was examined using phylogenetic analysis combining 24 adult morphology and chromosome number characters with 22 qualitative and quantitative floral development characters. Taxa sampled included nine species ofVeroniceae and as an outgroup one species each ofDigitaleae andVerbasceae. Veronica, Besseya, andSynthyris formed one clade, subtended byPseudolysimachion and then by theHebe group;Veronicastrum orWulfenia represent the basal-most branch of the tribe. The ancestral flowers of theVeroniceae may have been small with moderately short corolla tubes and lobes; long corolla tubes arose four times in the tribe and large corolla lobes twice.     

Euphorine phylogeny: the evolution of diversity in host-utilization by parasitoid wasps (Hymenoptera: Braconidae)

ABSTRACT.

• 1 New data on the phylogeny of the braconid subfamily Euphorinae supports the hypothesis that parasitism of adult insects by Euphorinae originated during parasitism of Chrysomelidae, a group whose larvae are ecologically coincident with adults.
• 2 Evolution of the habit of attacking the adult stage opened a new adaptive zone; subsequently the Euphorinae have diversified on to a phylogenetically greater variety of hosts than any other braconid subfamily.
• 3 Parasitism of eumastacid grasshoppers evolved from beetle parasitism in the tribe Perilitini.
• 4 The tribe Euphorini shows the greatest diversity of hosts utilized. Most attack Heteroptera; however, Chrysopopthorus diversified on to adult Chrysopidae, Euphoriella on to Psocoptera, and Cryptoxilos on to Scolytidae.
• 5 Parasitism of bark beetles (Scolytidae) has evolved independently in three genera: Cosmophorus, Cryptoxilos and Ropalophorus. This is the most specialized form of beetle parasitism by euphorines, since it involves direct parasitism of concealed hosts.
• 6 Parasitism of adult hymenopterans by the tribe Syntretini may be related to attacking hosts while they are foraging at flowers.
• 7 The pattern of diversification in the Euphorinae indicates several adaptive radiations within host orders, as well as a history of major host-shifts between phylogenetically distantly-related host groups: Coleoptera to Orthoptera; Coleoptera to Hymenoptera; Coleoptera to Heteroptera; Heteroptera to Neuroptera, Psocoptera, and back to Coleoptera. Both the‘host taxonomy’and‘host habitat’hypotheses of host-shifting are supported. Host-shifts have involved hosts occurring in the same micro-habitat and usually having similar feeding habits. This is consistent with current theory of host-location by means of host-produced kairomones and visual cues.

     

FLORAL DEVELOPMENT IN MANGROVE RHIZOPHORACEAE

The flowers of mangrove Rhizophoraceae (tribe Rhizophoreae) are adapted to three different pollination mechanisms. Floral development of representative species of all four genera suggests that the ancestral flower of the tribe was unspecialized, with successively initiated whorls of separate sepals, petals, antisepalous stamens, and antipetalous stamens; at its inception, the gynoecium had a united, half-inferior ovary and separate stigmatic lobes. This developmental pattern is found in Rhizophora mangle (wind-pollinated) and Ceriops decandra (insect-pollinated). In Kandelia, all floral organs distal to the sepals are initiated simultaneously, and there has apparently been an evolutionary amplification in the number of stamens to about six times the number of petals. Explosive pollen release evolved independently in C. tagal and in Bruguiera. In the former, all stamens belong to one whorl and arise simultaneously upon a very weakly differentiated androecial ring primordium. In Bruguiera, the androecial ring is pronounced, and two whorls of stamens arise upon it; the primordia of the antisepalous whorl arise first but are closer to the center of the apex than the antipetalous stamen primordia. The antisepalous stamens bend toward and are enclosed by the petals early in development. In all genera, the inferior ovary develops by zonal growth of receptacular tissue; additional intercalary growth above the placenta occurs in Bruguiera. In general, floral specialization is accompanied by an increase in the width of the floral apex compared to the size of the primordia, increasing fusion of the stylar primordia, and decreasing prominence of the superior portion of the ovary. Apparent specializations of petal appendages for water storage, including the presence of sub-terminal hydathodes (previously unreported in any angiosperm), were found in two species in which flowers remain open during the day but were absent from two species normally pollinated at night or at dawn. Distinctive tribal characteristics that may aid in phylogenetic analysis include the mode of development of the inferior ovary; the aristate, bifid, usually fringed petals that individually enclose one or more stamens; the intrastaminal floral disc; and the initially subepidermal laticiferous cell layer in the sepals and ovary.     

LOSS OF FLORAL ORGANS IN ATELEIA (LEGUMINOSAE: PAPILIONOIDEAE: SOPHOREAE)

Ateleia herbert-smithii is unique among legumes in being a wind-pollinated tree; carpellate and staminate flowers are restricted to different trees. Development of the two floral morphs, however, is essentially the same except for smaller carpels in functionally staminate flowers and failure of pollen formation in the anthers of functionally carpellate flowers. The floral development of Ateleia herbert-smithii is highly atypical among papilionoids and the tribe Sophoreae. Order of organ initiation is: sepals, solitary petal, carpel, and lastly all stamens in erratic order. Sepal order is unidirectional from the abaxial side, the normal pattern for papilionoids. Only one petal, the vexillum or standard, is initiated. Subsequent initiation is completely different from the usual unidirectional pattern of most papilionoids. A meristem ring forms, delimiting the solitary carpel centrally. Ten stamen primordia are initiated on the meristem ring, first laterally, then adaxially, and lastly abaxially. There is a tendency for antesepalous stamens to form before the antepetalous ones. The loss of four of the five petals is thought to alter drastically the subsequent organogeny as to position of organs and their order of initiation. Carpel initiation in Ateleia is precocious, but not uniquely so among legumes.     

Janusia anisandra (A. Juss.) Griseb (Malpighiaceae): The first case of enantiostyly in oil-flower species

Enantiostyly is a floral polymorphism characterized by style deflection to the right and left, which results in flowers with mirror images. To date, enantiostyly occurs only in species that offer pollen or nectar as floral resource. Here we describe the first case of enantiostyly in an oil-flower species. Janusia anisandra (A. Juss.) Griseb (Malpighiaceae) shows right and left-styled flowers in individuals occurring in an area of tropical dry forest in Northeastern Brazil. We described the floral morphology, investigate the reproductive system, and made focal observations of flower visitors behaviour. J. anisandra has morphological traits that are part of the floral conservatism found in the neotropical species of Malpighiaceae, which preserves features that are decisive for the interaction with oil-collecting bees of the Centridini tribe, performing a highly specialized pollination system. The six stamens (two major and four smaller), located in the center of the flower, characterizes heteranthery, an intrafloral polymorphism, in which the stamens differ in shape, size, and function and is commonly associated with enantiostyly. We identified the two floral morphs in the same individual, characterizing a monomorphic enantiostyly; each of the morphs differs by lateral displacement of the style to the right or to the left, always accompanied by one larger stamen. The species is moderately self-compatible. Four species of solitary bees of the genus Centris were registered visiting the two morphs of J. anisandra flowers. Centris aenea and C. fuscata were the main pollinators, performing 65% of the visits. This new discovery of a classical monomorphic enantiostyly in J. anisandra opens the way for investigations in the evolution of this system in oil-secreting flowers.