CONTRIBUTION OF POLLEN MORPHOLOGY TO SYSTEMATICS OF COLLOMIA (POLEMONIACEAE)

Pollen morphology of 14 species of Collomia (Polemoniaceae) was examined by light microscopy, and by both scanning and transmission electron microscopy. Four distinct pollen types were observed which are based principally upon 1) shape, number and distribution of apertures, and 2) surface sculpturing: Type 1—zonocolporate with striate ridges; Type 2—zonocolporate with striato-reticulate ridges; Type 3—pantoporate with radiate ridges; Type 4—pantoporate with irregularly reticulate ridges. Evaluation of pollen morphology reveals considerable discrepancy with respect to presently accepted sectional classification. Collomia grandiflora of sect. Collomia has a pollen type similar to that of members of sect. Collomiastrum and is now interpreted as representing an independent evolutionary line derived from the latter section. Collomia diversifolia of sect. Courtoisia has a pollen morphology similar to that of sect. Collomia. whereas C. heterophylla of the same section possesses pollen unique within the genus. This last pollen type shows close similarity to the pollen of members of Polemonium, Gilia, Leptodactylon, and Ipomopsis. Pollen of C. tinctoria and C. tracyi of sect. Collomia are anomalous within Polemoniaceae. No significant difference in exine stratification was discernible among the four pollen types.     

SYSTEMATIC SIGNIFICANCE OF SEED-SURFACE FEATURES IN ORTHOCARPUS (SCROPHULARIACEAE—SUBTRIBE CASTILLEJINAE)

Scanning electron microscope and light microscope examination of seed-coat features of 26 species of Orthocarpus have allowed recognition of many species-level differences (summarized in a key) and of three seed-coat types that parallel taxonomic subgroups but support realignments at generic and infrageneric levels. Type 1 seeds (subg. Orthocarpus, sect. Orthocarpus) have a lateral hilum, sculptured inner tangential seed-coat walls, and a tightly fitting outer seed coat. They are very similar to seeds of Cordylanthus. Seeds of Types 2 and 3 have a terminal hilum and membranous inner tangential cell walls. Type 2 seeds (subg. Orthocarpus, sects. Castillejoides and Cordylanthoides, with one exception) have a net-like, loosely fitting outer seed coat that shows close relationship to seeds of Castilleja. Inner tangential walls of Type 2 seeds normally rupture. Type 3 seeds (subg. Triphysaria, with two exceptions) have a tightly fitting outer seed coat and inner tangential walls are always retained. Seed features support evidence from floral morphology and chromosome numbers that Orthocarpus as currently recognized is not a monophyletic lineage.     

Testa and seed appendage morphology in Aeschynanthus (Gesneriaceae): phytogeographical patterns and taxonomic implications

The current sectional classification of the genus Aeschynanthus Jack, essentially based on seed morphology, presents some problems of species placement. A comparative SEM survey of seed and seed appendages was undertaken in order to assess the value of this classification. Seeds of 99 taxa (that is about two‐thirds of the estimated total) were examined and found to fall into two types, A and B. Type A has spiral testa cell orientation, papillae formed from a single cell and short smooth appendages. Type B is recognized by the straight orientation of the testa cells, combined with the presence of papillae formed from the raised ends of two adjacent cells on the long hair‐like appendages and usually on the testa. Only six of the investigated species did not fall into either category. Three have straight testa cell orientation combined with single‐cell papillae and short smooth appendages; the papillae and appendage characters place them in type A. Three have spiral testa cell orientation and short smooth appendages but the testa cells have slightly raised ends; these are also placed in Type A. The three subtypes in Type A are equivalent to the sections Haplotrichium s.s., Microtrichium and Aeschynanthus, but the divisions are less clear than those within Type B. However, other morphological characters support sectional separation. Type B subdivides into three: two subtypes equivalent to sections Polytrichium and Diplotrichium, and a third encompassing section Xanthanthos together with part of the current sect. Haplotrichium, and here referred to as sect. X. There is sufficient morphological correlation with seed type to make the sectional position of many species clear without recourse to seed, particularly in sects Polytrichium, Diplotrichium, Haplotrichium S.S. and Aeschynanthus. There is strong correlation between seed type and geographical distribution. Sects. Microtrichium and Aeschynanthus, with Type A seed, are essentially Malesian. Groups with Type B seed are largely confined to mainland south and south‐east Asia, except for sect. Polytrichium which is more widespread, possibly due to the greater effectiveness of a coma of hairs in wind dispersal. It is suggested that Type A seed, probably sect. Microtrichium, is the least determined and Type B sect. Polytrichium the most derived seed type. Based on these findings a revised key to the sections is provided.     

Understanding polysaccharide production and properties using seed coat mutants: future perspectives for the exploitation of natural variants

Background

The epidermal cells of the seed coat of certain species accumulate polysaccharides during seed development for cell wall reinforcement or release on imbibition to form mucilage. Seed-coat epidermal cells show natural variation in their structure and mucilage production, which could explain the diverse ecophysiological roles proposed for the latter. Arabidopsis mucilage mutants have proved to be an important tool for the identification of genes involved in the production of seed-coat polysaccharides.

Scope

This review documents genes that have been characterized as playing a role in the differentiation of the epidermal cells of the arabidopsis seed coat, the natural variability in polysaccharide features of these cells and the physiological roles attributed to seed mucilage.

Conclusions

Seed-coat epidermal cells are an excellent model for the study of polysaccharide metabolism and properties. Intra- and interspecies natural variation in the differentiation of these epidermal cells is an under-exploited resource for such studies and promises to play an important part in improving our knowledge of polysaccharide production and ecophysiological function.     

Intra- and inter-specific effects of mast seeding on seed fates of two sympatric <Emphasis Type="Italic">Corylus</Emphasis> species

We released seeds of two sympatric tree species, Corylus mandshurica (seed with thinner seed hull, higher nutrition) and C. heterophylla (seeds with thicker seed hull, lower nutrition) in the masting year of C. mandshurica in 2008, and C. heterophylla in 2009, respectively, to investigate how seed masting of the two sympatric Corylus species affects seed removal and dispersal fitness of the two species differently at both intra- and inter-specific levels. At intra-specific level, the authors found mast seeding of both C. mandshurica and C. heterophylla significantly reduced seed removal, seed consumption, but increased seed dispersal distance and seed dispersal fitness of the released seeds. Mast seeding of C. mandshurica increased seed caching of C. mandshurica. At inter-specific level, the authors found mast seeding of C. mandshurica reduced seed removal of C. heterophylla, but mast seeding of C. heterophylla did not significantly reduce seed removal of C. mandshurica. Mast seeding of C. mandshurica reduced seed consumption of C. heterophylla, while mast seeding of C. heterophylla reduced seed consumption of C. mandshurica. We found mast seeding of C. mandshurica significantly reduced seed dispersal distance of C. heterophylla, while mast seeding of C. heterophylla significantly increased seed dispersal distance of C. mandshurica. We found that mast seeding of C. mandshurica significantly increased seed dispersal fitness of C. heterophylla, while mast seeding of C. heterophylla did not significantly increase seed dispersal fitness of C. mandshurica. More studies are needed to reveal the ecological consequences of mast seeding at inter-specific or community-level. Seed traits may attribute the differences of mast seeding at inter-specific level. Because seeds with thinner seed hull and higher nutrition were more harvested and eaten by rodents, mast seeding of C. mandshurica might have reduced seed removal and seed consumption, but increased dispersal fitness of C. heterophylla (seeds with thicker seed hull, lower nutrition). Therefore, synchrony among species is, or is not, selectively beneficial to the focus species depends on seed traits which determine gains from mast seeding at inter-specific level.     

Seasonally different modes of seed dispersal in the prostrate annual, <Emphasis Type="Italic">Chamaesyce maculata</Emphasis> (L.) Small (Euphorbiaceae), with multiple overlapping generations

The modes of seed dispersal in the prostrate annual, Chamaesyce maculata, with multiple overlapping generations were investigated. We found that C. maculata has two modes of seed dispersal; autochory in the summer and myrmecochory in the autumn. Seasonally different modes of seed dispersal have not been known in other plant species. The large proportion of seeds produced in the summer was positioned further than the expanse of the parent plants by automatic mechanical seed dispersal. Therefore, autochory would be effective for avoiding competition between parent and offspring plants. No autochory occurred in the seeds produced in the autumn. The seeds of C. maculata without an elaiosome were dispersed by seed-collecting ants in the autumn. Although 18 ant species in total visited the plants of C. maculata at the 50 sites investigated, only two ant species, Tetramorium tsushimae and Pheidole noda frequently carried the seeds of C. maculata. The low frequency of seeds carried out of the nest by P. noda suggests that the workers of P. noda carry the seeds as food into their nest. So, P. noda might be a less effective seed disperser for C. maculata, corresponding to the effectiveness of seed dispersal by harvester ants. However, T. tsushimae ants frequently carried the seeds into and out of their nest, suggesting that T. tsushimae do not regard the seeds of C. maculata as a food resource. Thus, T. tsushimae may be an effective seed disperser for C. maculata.     

Seed morphology and its systematic implications for genus Oxytropis DC. (Fabaceae)

In the present study, seeds of 13 Oxytropis DC. species (including two latest synonyms) classified in subg. Oxytropis (sect. Dolichocarpon, sect. Chrysantha and sect. Eumorpha), subg. Euoxytropis (sect. Orobia) and subg. Phacoxytropis (sect. Protoxytropis, sect. Janthina and sect. Mesogaea) from Turkey were examined using light and scanning electron microscopy to evaluate the taxonomic relevance of macro- and micro-morphological seed characters. As a result of the study, species-specific characters have been determined. Seeds exhibit variation in size, shape, surface sculpturing pattern, hilum position and weight. Seeds ranged from 1.61 to 4.04 mm in length and from 1.02 to 2.56 mm in width. Five different seed shapes were recognised, as prolonged semielliptic, reniform, prolonged reniform, quadratic and cardiform, with a length to width ratio ranging from 1.02 ± 0.08 to 1.75 ± 0.27. Rugulate, rugulate–reticulate and lophate sculpturing patterns were observed in the studied species. According to the results, seed characters, such as the size (length, width and the length/width ratio), the shape, the surface sculpturing and the weight appear to have low taxonomic value in distinguishing subgenera, sections and species.     

The role of avian frugivores in germination of seeds of fleshy-fruited invasive alien plants

Many highly invasive plant species have fleshy fruits which are eaten by native frugivorous animals. These frugivores play an important role in long-distance seed dispersal, and may also affect germination success. The aim of this study was to determine whether generalist frugivores enhance or decrease seed germination of invasive alien species through pulp removal or seed coat abrasion, besides serving as dispersal agents. Fruits of four fleshy-fruited invasive alien plant species, namely Solanum mauritianum, Cinnamomum camphora, Lantana camara and Psidium guajava, were fed to three generalist avian frugivorous species, which have been observed feeding on these fruits in the wild. Seed retention time was recorded as this affects dispersal distance and the duration that seeds are exposed to the effects of the gut. Seeds removed from excreta, seeds from manually de-pulped fruit, and whole fruit were planted in soil trays housed in a greenhouse. Daily germination counts were done. Seed retention times differed significantly between bird species for all fruits, except those of C. camphora. However, all frugivores had a similar effect on the germination success of seeds of S. mauritianum, L. camara and P. guajava, showing that gut retention time was not important. Germination of seeds from manually de-pulped fruits did not differ from that of ingested seeds of all plant species, suggesting that seed coat abrasion was also not important. Pulp removal resulted in significantly higher germination rates, both in the two species with larger, multi-seeded fruit (S. mauritianum and P. guajava), and in the two species having single-seeded fruit with waxy exocarps (C. camphora and L. camara). Pulp removal also resulted in significantly earlier germination of L. camara and P. guajava seeds. Therefore, frugivores not only accelerate dispersal, but also greatly enhance seed germination of all fleshy-fruited invasive alien species in this study.     

SEED MORPHOLOGY AND SYSTEMATICS OF MENYANTHACEAE

Scanning electron microscopic investigations of seed morphology of the five genera of Menyanthaceae illustrate a remarkable diversity of seed characteristics for a small family. Seeds of the monotypic northern hemisphere Menyanthes and Fauria are unomamented and similar, and those of the monotypic Liparophyllum of New Zealand and Tasmania are similar to some Australian species of Villarsia. Seed characteristics within the larger genera Villarsia and Nymphoides are variable and mostly species specific, but do not lend support to taxonomic separation of these genera. Interspecific affinities postulated on other grounds are, in many instances, supported by seed morphology. Various seed-coat features are believed to aid in water or animal dispersal of the seeds of several species. Ant dispersal appears to be important for Villarsia and Nymphoides in Australia, but does not seem to occur in these genera or in other members of the family outside of Australia.     

Differences in the fruit maturation stages at which oviposition occurs among insect seed predators feeding on the fruits of five dipterocarp tree species

The seeds of dipterocarp trees are the main food resources for many species of weevils, bark beetles and small moths; however, for most seed‐eating insects on dipterocarp tropical trees, seed utilization patterns remain poorly investigated. This study aimed to determine the fruit maturation stages at which eggs are laid by different insect seed predators feeding on the seeds or fruits of the following five dipterocarp species: Dipterocarpus globosus, Dryobalanops aromatica, Shorea beccariana, S. acuta and S. curtisii, which reproduced during the same period. We investigated the occurrence frequencies of the insect seed predators at various growth stages by collecting both unfallen and fallen fruit on several occasions during the period of seed/fruit maturation in a tropical rainforest in Borneo from September to December 2013. Weevils and bark beetles were the dominant insect seed predators of the five tree species. One or two weevil species of Alcidodes, Damnux and/or Nanophyes preyed on the seeds of each of the five tree species, and one bark beetle species, Coccotrypes gedeanus, preyed on the seeds of all five tree species. Many larvae, pupae and adults of each weevil species were found in pre‐dispersal (unfallen) fruit, whereas bark beetles at various growth stages were found in post‐dispersal (fallen) fruit. These results suggested that, among the dominant insect seed predators of the five dipterocarp species, weevil species oviposit on pre‐dispersal fruit and begin their larval growth before seed dispersal, whereas the oviposition and larval development of bark beetle species occurs in post‐dispersal fruit.     

Responses of pre‐dispersal seed predators to sequential flowering of Dipterocarps in Malaysia

Many species of Dipterocarpaceae and other plant families reproduce synchronously at irregular, multi‐year intervals in Southeast Asian forests. These community‐wide general flowering events are thought to facilitate seed survival through satiation of generalist seed predators. During a general flowering event, closely related Shorea species (Dipterocarpaceae) stagger their flowering times by several weeks, which may minimize cross pollination and interspecific competition for pollinators. Generalist, pre‐dispersal seed predators might also track flowering hosts and influence predator satiation. We addressed the question of whether pre‐dispersal seed predation differed between early and late flowering Shorea species by monitoring flowering, fruiting and seed predation intensity over two general flowering events at the Pasoh Research Forest, Malaysia. Pre‐dispersal insect seed predators killed up to 63 percent of developing seeds, with Nanophyes shoreae, a weevil that feeds on immature seeds being the most important predator for all Shorea species. This weevil caused significantly greater pre‐dispersal seed predation in earlier flowering species. Long larval development time precluded oviposition by adults that emerged from the earliest flowering Shorea on the final flowering Shorea. In contrast, larvae of weevils that feed on mature seeds before seed dispersal (Alcidodes spp.), appeared in seeds of all Shorea species almost simultaneously. We conclude that general flowering events have the potential to satiate post‐dispersal seed predators and pre‐dispersal seed predators of mature fruit, but are less effective at satiating pre‐dispersal predators of immature fruit attacking early flowering species.     

What are the consequences of ant–seed interactions on the abundance of two dry-fruited shrubs in a Mediterranean scrub?

Strong interactions between dry-fruited shrubs and seed-harvesting ants are expected in early successional scrubs, where both groups have a major presence. We have analysed the implications of the seed characteristics of two dry-fruited shrub species (Coronilla minima and Dorycnium pentaphyllum) on seed predation and dispersal mediated by harvester ants and the consequences of these processes on spatio-temporal patterns of plant abundance in a heterogeneous environment. We found that large C. minima seeds were collected much more (39%) than small D. pentaphyllum seeds (2%). However, not all of the removed seeds of these plant species were consumed, and 12.8% of the seeds were lost along the trails, which increased dispersal distances compared with abiotic dispersal alone. Seed dropping occurred among all microhabitats of the two plant species, but especially in open microhabitats, which are the most suitable ones for plant establishment. The two plant species increased their presence in the study area during the study period: C. minima in open microhabitats and D. pentaphyllum in high vegetation. The large size of C. minima seeds probably limited the primary seed dispersal of this species, but may have allowed strong interaction with ants. Thus, seed dispersal by ants resulted in C. minima seeds reaching more suitable microhabitats by means of increasing dispersal distance and redistribution among microhabitats. In contrast, the smaller size of D. pentaphyllum seeds arguably allows abiotic seed dispersal over longer distances and colonization of all types of microhabitats, although it probably also limits their interaction with ants and, consequently, their redistribution in suitable microhabitats. We suggest that dyszoochory could contribute to the success of plant species with different seed characteristics in scrub habitats where seeds are abundantly collected by seed-harvesting ants.     

Germination response of four pasture species to temperature,light, and post-harvest period

Abstract

The purpose of this research was to explore the effect of temperature, light, and post-harvest period, and their interactions, on seed germination ecology of four common pasture species in the Mediterranean environment. Mature seeds of Diplotaxis erucoides, Hirschfeldia incana, Hyoseris scabra (Mediterranean distribution) and Sonchus oleraceus (cosmopolitan distribution) were subjected to seven constant temperatures (10–40°C, at intervals of 5°C) under continuous darkness, or a 12 h/12 h light/dark photoperiod at 30, 150 and 270 days after harvest (DAH). Cumulative germination and germination speed were determined. In all the tested species, except S. oleraceus, light significantly enhanced germination. S. oleraceus seeds maintained germination values over 90%, in a wide range of temperatures (10–35°C), in the dark as well as in light. Seeds of H. incana germinated well soon after seed dispersal. In D. erucoides and H. scabra, germination increased with storage period, while in S. oleraceus there was no effect of seed age. In all the species, moreover, no germination was recorded at 40°C. Temperature, light, and post- harvest requirement may be regarded as an adaptation strategy to ensure optimal conditions for seedling development and survival in Mediterranean species, while the species with a cosmopolitan distribution germinates under almost all tested conditions.     

The dispersal and deposition of hydrochorous plant seeds in drainage ditches

1. Surface water is an important dispersal vector for wetland plant species. However, most previous studies on hydrochory (i.e. water dispersal) have focused on ecosystems with relatively rapid water flow. Therefore, there is a need to study such dispersal in slow‐flowing or stagnant waterbodies, such as drainage ditches, which might act as dispersal corridors between habitat patches. 2. To gain insight into the mechanisms by which seeds are transported in drainage ditches, the effect of the velocity of wind and water on the rate of transport of floating seeds of three wetland species (Carex pseudocyperus L., Iris pseudacorus L. and Sparganium erectum L.) was investigated. Furthermore, in release and retrace experiments with painted C. pseudocyperus seeds, a number of factors potentially determining the probability of seed deposition were investigated. 3. Net wind speed was found to be the main factor determining the rate at which seeds are transported in drainage ditches. No relation between water flow at middepth in the ditches and seed transport was found. Wind speed and flow at the water surface were positively related. The effect of wind speed on the rate of transport of floating seeds was greater for S. erectum seeds, because a greater ratio of their volume protrudes from the water, than for C. pseudocyperus and I. pseudacorus seeds. 4. The principal factors that determine seed deposition were aquatic plant cover, ditch slope and indentations in the ditch bank. Seeds changed direction if the wind direction changed, or if there was a bend in the ditch. The final pattern of deposition was related to mean net wind speed. Mean transport distance after 2 days varied between 34 and 451 m. 5. Unlike in rivers, seed transport in ditches was determined by wind speed and direction, enabling multidirectional seed dispersal. We conclude that in slow‐flowing waters, wind is a more important driver for hydrochorous seed transport than the flow of water. This sheds a new light on hydrochory and has important consequences for the management of otherwise fragmented wetland remnants.     

Splash seed dispersal by raindrops

Splash seed dispersal by raindrops was investigated for plants in southern Japan. Nine families, 10 genera and 19 species were confirmed as raindrop-dispersed plants. The 10 genera were Gentiana, Gratiola, Chrysosplenium, Mazus, Mitella, Ophiorrhiza, Sagina, Sedum, Trigonotis and Veronica. The method of splash rain dispersal in these species was clarified. Raindrop-dispersed species were all small herbaceous plants with a vertical pedicel and an apically opening fresh capsule when the seeds mature. Open capsules were cup-shaped or boat-shaped and can accommodate raindrops easily. The raindrops splashed the seeds from the capsule. In general, the seeds weighed very little, but they were heavier than powder or dust seeds dispersed by wind. A strong negative correlation was found between seed weight and the number of seeds per capsule. In the case of Trigonotis brevipes (Maxim.) Maxim., raindrops were received into the cup-shaped calyx-tube and dispersed the fruitlets. Some species, such as Gentiana thunbergii (G. Don) Griseb., Gentiana zollingeri Fawcett and Ophiorrhiza japonica Blume, had hydroscopic movement capsules that opened widely only when wet. Raindrop-dispersed plants were found in various habitats. For example, some plants grew together on rocks along the mountain torrents where splash water could easily be caught. The results of the laboratory and field experiments indicated that the dispersal distance of seeds by raindrops was 1m or less. For small herbaceous plants, splash dispersal by rain might be an effective and advantageous method of seed dispersal because dispersal is not affected by plant height.     

White‐tailed deer as the last megafauna dispersing seeds in Neotropical dry forests: the role of fruit and seed traits

Endozoochory is a prominent form of seed dispersal in tropical dry forests. Most extant megafauna that perform such seed dispersal are ungulates, which can also be seed predators. White‐tailed deer (Odocoileus virginianus) is one of the last extant megafauna of Neotropical dry forests, but whether it serves as a legitimate seed disperser is poorly understood. We studied seed dispersal patterns and germination after white‐tailed deer gut passage in a tropical dry forest in southwest Ecuador. Over 23 mo, we recorded ca 2000 seeds of 11 species in 385 fecal samples. Most seeds belonged to four species of Fabaceae: Chloroleucon mangense, Senna mollissima, Piptadenia flava, and Caesalpinia glabrata. Seeds from eight of the 11 species dispersed by white‐tailed deer germinated under controlled conditions. Ingestion did not affect germination of C. mangense and S. mollissima, whereas C. glabrata showed reduced germination. Nevertheless, the removal of fruit pulp resulting from ingestion by white‐tailed deer could have a deinhibition effect on germination due to seed release. Thus, white‐tailed deer play an important role as legitimate seed dispersers of woody species formerly considered autochorous. Our results suggest that more research is needed to fully understand the ecological and evolutionary effects of the remaining extant megafauna on plant regeneration dynamics in the dry Neotropics.     

Endozoochory and Fire as Germination Triggers in Neotropical Dry Forests: an Experimental Test

Endozoochory and fire are crucial ecological factors determining germination success and recruitment in many plant species. Fire is a well‐known germination trigger while endozoochory may allow seed dispersal along with an increase in germination. Their interaction has rarely been addressed, however, even though both factors are pervasive in human‐transformed ecosystems like most Neotropical Dry Forests (NDF). For three common Mesoamerican tree species (Acacia pennatula, Enterolobium cyclocarpum, and Guazuma ulmifolia), we used feeding trials to assess the preference of cattle, which are their main seed dispersal agent. We also experimentally tested the interaction between gut passage and fire as triggers of germination. The fruits of the three species were eaten by cattle, but the small seeds of G. ulmifolia were ingested 10‐fold more than those of the other species. While gut passage did not have any effect on germination, heat‐shocks above 90 °C increased the number of germinating seeds by 15 percent. These results suggest that cattle may be a key dispersal vector in NDF, but that fire may be an important germination trigger. Physical dormancy in these species may have been selected for by extinct megaherbivores because it was a key trait ensuring seed survival after gut passage. However, in light of the recent expansion of cattle‐ranching and fire occurrence in NDF, it has become a useful exaptation facilitating the colonization of disturbed areas.     

Systematic implications of seed coat diversity in Gaultherieae (Ericaceae)

The seed morphology of 90 samples from 83 species of tribe Gaultherieae (Chamaedaphne, Diplycosia, Eubotryoides, Eubotrys, Gaultheria and Leucothoe) and relatives in tribes Andromedeae (Andromeda and Zenobia) and Vaccinieae (Satyria) was investigated with stereoscopic and scanning electron microscopy. Seeds exhibit variation in shape, colour, size, wing, hilum region, primary ornamentation and epidermal cells. Non‐metric multidimensional scaling (NMDS) analysis based on selected seed characters supports the affinities of some groups within Gaultherieae at various taxonomic levels. Seed characters corroborate the delimitation of Andromeda, Chamaedaphne, Leucothoe, Satyria and Zenobia and Gaultheria series Trichophyllae, series Hispidulae, section Amblyandra and section Brossaeopsis. Parsimony optimization of seed characters onto a previously published phylogenetic estimate of Gaultherieae reveals that small seeds have evolved from larger seeds and an areolate seed coat has evolved from a reticulate seed coat. Optimization also suggests that several seed character states are synapomorphies or potential synapomorphies for some major clades of Gaultherieae. Seeds of Gaultherieae from East Asia, temperate North America and the Pacific are more diverse than those from tropical America. Samples from the eastern Himalaya possess the highest variation in seed morphology. The wing and bulging edge cells observed in seeds of Leucothoe suggest dispersal by wind. © 2010 The Linnean Society of London, Botanical Journal of the Linnean Society, 2010, 162 , 477–495.     

Seed dispersal by lizards on a continental‐shelf island: predicting interspecific variation in seed rain based on plant distribution and lizard movement patterns

Aim We estimated the patterns of seed deposition provided by the eyed lizard, Timon lepidus, and evaluated whether these patterns can be generalized across plant species with different traits (fruit and seed size) and spatial distributions. Location Monteagudo Island, Atlantic Islands National Park (north‐western Spain). Methods We radio‐tracked seven lizards for 14 days and estimated their home ranges using fixed kernels. We also geo‐referenced all fruit‐bearing individuals of four plant species dispersed by eyed lizards in the study area (Corema album, Osyris alba, Rubus ulmifolius and Tamus communis), measured the passage time of their seeds through the lizard gut, and estimated seed predation in four habitats (bare sand, grassland, shrub and gorse). Seed dispersal kernels were estimated using a combination of these data and were combined with seed predation probability maps to incorporate post‐dispersal seed fate (‘seed survival kernels’). Results Median seed gut‐passage times were around 52–98 h, with maximum values up to 250 h. Lizards achieved maximum displacement in their home ranges within 24–48 h. Seed predation was high (80–100% of seeds in 2 months), particularly under Corema shrub and gorse. Seed dispersal kernels showed a common pattern, with two areas of preferential seed deposition, but the importance of these varied among plant species. Interspecific differences among dispersal kernels were strongly reduced by post‐dispersal seed predation; hence, seed survival kernels of the different plant species showed high auto‐ and pairwise‐correlations at small distances (< 50 m). As a result, survival to post‐dispersal seed predation increased with dispersal distance for O. alba and T. communis, but not for C. album. Main conclusions Seed dispersal by lizards was determined primarily by the interaction between the dispersers’ home ranges and the position of the fruit‐bearing plants. As a result, seed rain shared a common template, but showed considerable variation among species, determined by their specific spatial context. Seed predation increased the spatial coherence of the seed rain of the different species, but also resulted in contrasting relationships between seed survival and dispersal distance, which may be of importance for the demographic and evolutionary processes of the plants.     

Seed dispersal in Erythronium grandiflorum (Liliaceae)

Primary and secondary seed dispersal was investigated for the glacier lily Erythronium grandiflorum in the Colorado Rocky Mountains. These heavy seeds have no obvious adaptations for biotic or abiotic dispersal, but can be thrown short distances when the dehiscent fruits are shaken by wind. We used sticky traps to measure primary transport of seeds up to 1 m away from individual plants. A seed cafeteria experiment examined the role of ants and rodents in secondary seed transport. Primary dispersal by wind was positively skewed and median transport distances were influenced by variation in plant height. Secondary dispersal was negligible compared to Viola nuttallii, an elaiosome-bearing species. Thus, seed dispersal was highly restricted in E. grandiflorum, and a 1 m radius encompassed the modal section of the seed dispersal curve. The seed dispersal component of gene flow was quantified and combined with previous measurements of pollen flow to yield a more complete estimate of Wright's neighborhood size, N _e, for E. grandiflorum. The lack of a special seed dispersal mechanism in E. grandiflorum is discussed in terms of a source-sink model for seedling establishment with respect to distance from the parental plants.