Reproductive features of Celmisia species (Asteraceae) in relation to altitude and geographical range in New Zealand

A range of seed and flower characters was examined in 37 species of the New Zealand genus Celmisia (Asteraceae) to determine whether there were any relationships between reproductive features and the geographic or altitudinal ranges of the species. Using published sources and herbarium material, flower attractiveness to pollinators was measured in terms of capitulum size and ray/disc length ratio. Dispersibility was measured in terms of seed dry weight, seed terminal velocity, pappus/seed length ratio, and scape/leaf length ratio. Altitude (minimum and maximum) and geographic ranges (number of 1^o latitude x 1^o longitude squares occupied) were obtained from published sources. A multivariate principal components analysis using 12 morphological characters revealed the presence of five groups of species differing in capitulum size, seed weight, pappus length, number of pappus bristles, leaf length and scape length. Linear regressions showed that altitude was significantly and negatively related to seed dry weight and capitulum size, and positively to scape/leaf length ratio. Geographic range is negatively related to capitulum size, and positively to ray/disc ratio and altitudinal range. Amongst the seed features measured, seed weight was the best predictor of terminal velocity (an inverse measure of dispersability), but lighter seeds also had a higher pappus/seed length ratio. The frequency distribution of the geographic ranges of the species is highly skewed, with many local species (86% occurring in 15 or fewer one‐degree squares) and very few common ones. Two species (C. gracilenta and C. graminifolia) are notably more common than all the others. A comparison of these species with the others shows that, on average, they have lighter seeds with more bristles, taller scapes and higher ray/disc ratios, but have smaller capitula. The low geographic abundance of the rare species could not readily be attributed to any specific reproductive feature, possibly because of the multiple types of rarity represented within the genus.     

Are the best dispersers the best colonizers? Seed mass,dispersal and establishment in <Emphasis Type="Italic">Carduus</Emphasis> thistles

Negative correlations between dispersal and establishment are often reported in the plant literature; smaller seeds tend to disperse better but germinate less well, and produce smaller seedlings. However, because dispersal capacity is often quantified using proxies, such as the settling velocity of wind-dispersed seeds, little is known about the exact shape of this negative relationship, and how it is modified by other plant traits and environmental conditions. We studied the dispersal-establishment relationship in two wind-dispersed thistles (Carduus nutans and Carduus acanthoides). We applied a mechanistic wind dispersal model (WALD) to seeds released under a range of environmental conditions, and tested germination and seedling growth under standardized conditions in a greenhouse. Dispersal distance and establishment (germination and seedling growth) were not significantly correlated, although in both species smaller seeds dispersed farther, and showed lower germination and lower seedling growth rates. This apparent paradox can partly be explained by the significant influence of other factors such as release height and environment (wind and vegetation), which explained more variation in dispersal than did terminal velocity. Another potential explanation is the variation in seed traits: germination is strongly positively related to seed mass, weakly positively related to plume loading, but not significantly related to terminal velocity. This weakening of the correlation with germination is due to additional layers of trait (co)variability: for instance, seed mass and pappus size are positively correlated, and thus big seeds partially compensate for the negative effect of seed mass with larger pappi. Our mechanistic approach can thus lead to a better understanding of both potentially opposing selection pressures on traits like seed mass, and diluting effects of other seed, plant and environmental factors.     

Morphologic and Aerodynamic Considerations Regarding the Plumed Seeds of Tragopogon pratensis and Their Implications for Seed Dispersal

Tragopogon pratensis is a small herbaceous plant that uses wind as the dispersal vector for its seeds. The seeds are attached to parachutes that increase the aerodynamic drag force and increase the total distance travelled. Our hypothesis is that evolution has carefully tuned the air permeability of the seeds to operate in the most convenient fluid dynamic regime. To achieve final permeability, the primary and secondary fibres of the pappus have evolved with complex weaving; this maximises the drag force (i.e., the drag coefficient), and the pappus operates in an “optimal” state. We used computational fluid dynamics (CFD) simulations to compute the seed drag coefficient and compare it with data obtained from drop experiments. The permeability of the parachute was estimated from microscope images. Our simulations reveal three flow regimes in which the parachute can operate according to its permeability. These flow regimes impact the stability of the parachute and its drag coefficient. From the permeability measurements and drop experiments, we show how the seeds operate very close to the optimal case. The porosity of the textile appears to be an appropriate solution to achieve a lightweight structure that allows a low terminal velocity, a stable flight and a very efficient parachute for the velocity at which it operates.     

Influence of selfing and maternal effects on life-cycle traits and dispersal ability in the herb Hypochaeris radicata (Asteraceae)

The ecological and evolutionary implications of dispersal are many. Pollination type and maternal effects may affect plant fitness traits, including life-cycle traits as well as dispersal ability. This study investigated the joint influence of pollination type and maternal effects on both life-cycle traits and dispersal ability in the herb Hypochaeris radicata . We conducted experimental crosses to obtain selfed and outcrossed progeny. Individual seeds and their pappuses were measured to determine seed terminal velocity. Seed size was also used to assess maternal effects. Selfing dramatically decreased seed set, indicating that H. radicata is self-incompatible. However, the few selfed seeds produced outperformed outcrossed seeds in seed size and flowering probability, surely as a result of an effective reallocation of resources among selfed seeds. None of the life-cycle traits was affected by seed size, the estimate of maternal effects. Selfed seeds were larger and bore a smaller pappus than outcrossed seeds. As a result, dispersal ability was lower for selfed than outcrossed seeds. Several factors, such as the low proportion of plants that produced selfed seeds, the low number of selfed seeds produced per plant, and the lack of self-fertility mechanisms might act in concert to prevent the evolution of selfing in H. radicata .  © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 146 , 163–170.     

Evolutionarily stable resource allocation for production of wind-dispersed seeds

We developed a game-theoretic model for wind-dispersed seed production to examine the seed mass–dispersal ability relationship and the evolutionarily stable distance of seed dispersal in terms of exploitation of safe sites. We assumed trade-offs between masses of the embryo (including albumen) and the wind-dispersal structures per seed, and also between seed mass and number of seeds per parent. We showed that ESS wing-loading is independent of embryo mass; that is, heavy seeds are not poor dispersers if the cost of producing wind-dispersal structures per unit area is constant. The ESS embryo mass per seed depends only on the factors which determine the probability of a seedling being established from a seed. However, wing-loading was found to increase with embryo mass when the change in length was isometric and there was a negative correlation between seed mass and dispersal ability. Thus, the area–mass relationship in wind-dispersal structures may have large effects on the ESS production of wind-dispersed seeds. On the other hand, given that only a limited number of adults can be established at a safe site, the ESS seed dispersal distance depends on the relative degree of sib to non-sib competition. A parent disperses its seeds over a wide area to exploit many safe sites if sib competition is strong. However, it disperses its seeds within a narrow area if the mean number of parents per unit area is large, or if non-sib competition is strong. Thus, in addition to an upper limit on the number of adults per safe site, the degree of sib and non-sib competition may be important for the ESS dispersal distance in wind-dispersed seeds. This revised version was published online in July 2006 with corrections to the Cover Date.     

A Triassic seed with an angiosperm‐like wind dispersal mechanism

The earliest record of a seed with a pappus‐like, parachute seed dispersal mechanism, Edenia villisperma gen. et sp. nov., is described from the Upper Triassic of the eastern United States. The seed is small and roughly triangular. Clusters of long hairs emerge from a whorl of at least five circular scars just below the proximal end. This morphology indicates that the hair clusters represent modified lateral structures similar to the pappus of several eudicot angiosperm groups, but probably representing a case of convergent evolution of a similar structure in a gymnosperm. The seeds are usually found isolated, but one specimen indicates that they were born tightly packed together on an axis. A few earlier records exist of dispersal hairs, but this is the first clearly indicating a pappus‐like structure. Although the exact affinities of Edenia are uncertain, this seed demonstrates that plants with highly advanced wind dispersal mechanisms occurred at least 55 million years earlier than previously thought.     

Safflower susceptibility and response to feeding by grasshoppers

Feeding by three grasshopper species, Camnula pellucida, Melanoplus packardii and Melanoplus sanguinipes, on three safflower (Carthamus tinctorius) lines for a 6-wk period from anthesis was monitored under field conditions. Ratings of feeding damage to different plant parts (leaves, floral parts, capitula, and peduncles) and measurements after termination of feeding (dry weight, seed yield, seed weight, seeds per capitulum, and capitula per row) were compared among grasshopper species and safflower lines. The Melanoplus species fed preferentially on leaves, floral parts, and capitula, while C. pellucida exhibited only peduncle feeding, which resulted in head clipping. Defoliation of 20 to 30% was associated with significant increases in total dry matter, seed yield, and number of capitula. Further defoliation resulted in decreases. The safflower lines differed in response to grasshopper feeding. S-208 was most susceptible to defoliation by grasshopper feeding, exhibiting decreased dry weight, seed yield, and capitula number. Lesaf 34C-00 was most tolerant and only M. packardii caused significant dry weight and seed yield reductions. Feeding by C. pellucida on this line resulted in an overall seed yield increase. Feeding by M. sanguinipes on Seedtec-5 resulted in yield increases of up to 16%. It appears that certain grasshopper species can increase seed yield in some safflower lines by stimulating the production of additional capitula. Therefore, moderate populations of such grasshoppers in fields of appropriate safflower cultivars do not necessarily require control.     

Contrast adaptation to time constraints on development of two pre-dispersal predators of dandelion (<Emphasis Type="Italic">Taraxacum officinale</Emphasis>) seed

Pre-dispersal seed predators of quickly maturing inflorescences of Asteraceae are constrained by shortage of development time. At seed dispersal, they should pupate or, if still immature, relocate into another inflorescence. To investigate how dominant coleopteran predators of dandelion seed, Glocianus punctiger (Curculionidae) and Olibrus bicolor (Phalacridae), cope with time limitation we combined observation (development and temperature of dandelion capitulum, thermal constants of predator development, age structure of larval populations at seed dispersal) and analogy (“rate isomorphy” in predator development, comparing “model” coleopteran species with similar temperature requirements). Development of a dandelion capitulum takes 21 days. The time available to G. punctiger (140–190 day degrees, development threshold 6.3°C) is sufficient to complete development and pupate after seed dispersal. By contrast, only 30–50 day degrees are available to O. bicolor (threshold 13.5°C) and this is not enough to complete development and consequently immature larvae should move to other capitula to continue feeding until pupation. These contrast strategies which are determined by this thermal adaptation, are accompanied by differences in larval morphology. The “cold adapted” G. punctiger has an apodous larva not capable of migrating between capitula while the “warm adapted” O. bicolor has a mobile campodeiform larva capable of migration.     

Urbanization alters plastic responses in the common dandelion Taraxacum officinale

Urban environments expose species to contrasting selection pressures relative to rural areas due to altered microclimatic conditions, habitat fragmentation, and changes in species interactions. To improve our understanding on how urbanization impacts selection through biotic interactions, we assessed differences in plant defense and tolerance, dispersal, and flowering phenology of a common plant species (Taraxacum officinale) along an urbanization gradient and their reaction norms in response to a biotic stressor (i.e., herbivory). We raised plants from 45 lines collected along an urbanization gradient under common garden conditions and assessed the impact of herbivory on plant growth (i.e., aboveground biomass), dispersal capacity (i.e., seed morphology), and plant phenology (i.e., early seed production) by exposing half of our plants to two events of herbivory (i.e., grazing by locusts). Independent from their genetic background, all plants consistently increased their resistance to herbivores by which the second exposure to locusts resulted in lower levels of damage suffered. Herbivory had consistent effects on seed pappus length, with seeds showing a longer pappus (and, hence, increased dispersal capacities) regardless of urbanization level. Aboveground plant biomass was neither affected by urbanization nor herbivore presence. In contrast to consistent responses in plant defenses and pappus length, plant fitness did vary between lines. Urban lines had a reduced early seed production following herbivory while rural and suburban lines did not show any plastic response. Our results show that herbivory affects plant phenotypes but more importantly that differences in herbivory reaction norms exist between urban and rural populations.     

胡杨种子萌发过程中几种相关酶的活性变化

在室温条件下,胡杨种子保留冠毛贮藏可适当延长其生命力;室温贮藏带冠毛的胡杨种子,前20 d萌发率降低幅度不大.随着种子贮藏时间的延长,过氧化物酶(POD)、过氧化氢酶(CAT)和超氧化物歧化酶(SOD)活性均先上升后下降,峰值出现时间与种子室温贮藏20 d相对应;脱氢酶活性先上升后下降再回升,峰值出现时间也与种子室温贮藏20 d相对应;酸性磷酸酯酶(ACP)活性与种子萌发率同步下降.室温贮藏40 d的带冠毛胡杨种子仍有22.3%的萌发率.     

Geigeria alata in the Namib desert: seed heteromorphism in an extremely arid environment

Abstract. Seed heteromorphism in annual Geigeria alata in the Namib Desert was investigated in relation to environmental conditions. Geigeria alata shows heteromorphism in seed dispersal distance depending on the position of the seeds on the parent plant. Seeds produced in capitula on branches (aerial) travel long distances, while seeds produced at the base of the plant remain in the vicinity of the parent plant. The ratio of aerial to basal seed production was investigated under different environmental conditions following an aridity gradient. Although there were significant differences in seed and capitula production between seasons and between different positions on the plant, no overall trend was found with increasing aridity.     

Field experiments on seed dispersal by wind in ten umbelliferous species (Apiaceae)

This report presents data from experiments on seed dispersal by wind for ten species of the family Apiaceae. Seed shadows were obtained in the field under natural conditions, using wind speeds between four and ten m/s. The flight of individual seeds was followed by eye, and seed shadows were acquired, with median distances varying from 0.7 to 3.1 m between species. Multiple regression models of wind speed and seed weight on dispersal distance were significant for six out of ten species; wind speed had significant effects in seven cases, but seed weight only once. A good correlation between mean terminal falling velocity of the seeds of a species and median dispersal distance, indicates the promising explanatory power that individual terminal velocity data might have on dispersal distance, together with wind speed and turbulence. The theory that seeds that seem to be adapted to wind dispersal travel much longer distances than seeds that have no adaptation was tested. Flattened and winged seeds were indeed found to be transported further by wind, but not much further. Moreover, the species with wind-adapted seeds were also taller, being an alternative explanation since their seeds experienced higher wind speeds at these greater heights. Furthermore, flattened and winged seeds were disseminated from ripe umbels at lower wind speeds in the laboratory. This means that the observed difference in dispersal distance would have been smaller when species specific thresholds for wind speed were incorporated in the field experiments. We argue therefore, that seed morphology is not always the best predictor in classifying species in groups with distinctly different dispersal ability.     

Water as a Storage Medium for Elaeis guineensis (pisifera) Seeds under Aseptic Conditions

Over 50 per cent germination has been obtained from Elaeis guineensisform pisifera seeds stored in unaerated sterile distilled waterfor 6 months. The moisture levels of the seeds and excised embryoswere of the same order (20–30 and 60–70 per cent,respectively) as those of fully imbibed fresh seeds. The implicationsof an apparent lower oxygen requirement by seeds stored underwater as against germinating seeds are discussed in the contextof the successful storage. Elaeis guineensis, pisifera, germination, seed dormancy, embryo     

Improving measurements of the falling trajectory and terminal velocity of wind‐dispersed seeds

Seed dispersal by wind is one of the most important dispersal mechanisms in plants. The key seed trait affecting seed dispersal by wind is the effective terminal velocity (hereafter “terminal velocity”, V _t ), the maximum falling speed of a seed in still air. Accurate estimates of V _t are crucial for predicting intra‐ and interspecific variation in seed dispersal ability. However, existing methods produce biased estimates of V _t for slow‐ or fast‐falling seeds, fragile seeds, and seeds with complex falling trajectories. We present a new video‐based method that estimates the falling trajectory and V _t of wind‐dispersed seeds. The design involves a mirror that enables a camera to simultaneously record a falling seed from two perspectives. Automated image analysis then determines three‐dimensional seed trajectories at high temporal resolution. To these trajectories, we fit a physical model of free fall with air resistance to estimate V _t . We validated this method by comparing the estimated V _t of spheres of different diameters and materials to theoretical expectations and by comparing the estimated V _t of seeds to measurements in a vertical wind tunnel. V _t estimates closely match theoretical expectations for spheres and vertical wind tunnel measurements for seeds. However, our V _t estimates for fast‐falling seeds are markedly higher than those in an existing trait database. This discrepancy seems to arise because previous estimates inadequately accounted for seed acceleration. The presented method yields accurate, efficient, and affordable estimates of the three‐dimensional falling trajectory and terminal velocity for a wide range of seed types. The method should thus advance the understanding and prediction of wind‐driven seed dispersal.     

Wheat Viability at High Moisture Content under Hermetic and Aerobic Storage Conditions

Wheat seeds (Triticum durum) were stored under both hermeticand aerobic conditions at 25 °C with moisture contents from15 to 33 per cent. Under hermetic storage, seeds lost viabilitymore rapidly the higher the moisture content, whereas in aerobicstorage, seed longevity was enhanced as the moisture contentwas increased from 24 to 31 per cent, and over this range ofmoisture content the seeds survived longer under aerobic thanhermetic storage. On the contrary, an apparent reversal of thistrend occurred when moisture content was increased above 31per cent. The possibility that the changes in longevity occurring at highermoisture contents might be due to the activation of seed metabolismwas supported by the enhanced incorporation of [³H]leucine intoTCA insoluble material (indicating increased protein synthesis)and the reduced leakage of glucose (indicating increased membranerestitution) when seeds were allowed to achieve higher moisturecontents during the prehydration period. The highest level ofseed activation was found in seeds preconditioned to about 31per cent moisture content. Moreover, these seeds, when subsequentlystored under aerobic conditions, maintained a higher rate ofprotein synthesis and lower membrane permeability during thestorage period than seeds at lower water contents. It is suggested that seeds stored at a sufficient hydrationlevel in the presence of oxygen can sustain an effective metabolismduring extended storage, thus permitting the repair of cellulardamage. However, it might be possible that at about 33 per centmoisture content seed could suffer from an excessive advancementof metabolism. Triticum durum, seed storage, effects of high moisture content and oxygen     

Seed Viability Constants for Lettuce

Seeds of two lettuce cultivars (Lactuca sativa L., cv. Meikoninginand cv. Grand Rapids) were hermetically stored with constantmoisture contents ranging between 3.6 and 17.9 per cent (freshweight basis) at constant temperatures ranging between 5 and75 °C. The decline with time in percentage germination andpercentage normal seedlings was determined for each storagetreatment. The data were fitted to an equation which containsthe constants: K₁, the probit of the initial percentage germinationor normal seedlings; K_E, a species constant; C_W, the constantof a logarithmic moisture term; C_H, the constant of a lineartemperature term and C_Q, the constant of a quadratic temperatureterm. Regression analysis of data from storage periods up to5.5 years at temperatures of 5–75 °C and seed moisturecontents of 3.6–13.6 per cent yielded the following values:K_E= 8.218, C_W=4.797±0.163, C_H=0.0489±0.0050 andC_Q=0.000365±0.000056. Although this equation consistentlyprovided a better fit, simplified equations, assuming eithera log-linear relationship between seed longevity and temperature,or a log-linear relationship between seed longevity and bothmoisture content and temperature, accounted for more than 94per cent of the variation at the restricted temperature rangeof 5–40 °C. Longevity of the same seed lots at sub-zero temperatures (–5,–10 and –20 °C) was studied in separate tests.Freezing damage, resulting in abnormal seedlings in the germinationtest, occurred at –20 °C when the moisture contentof the seeds exceeded 12 per cent. No decline in percentagenormal seedlings was observed after a storage period of 18 monthsor longer at –20 °C, provided the seed moisture contentdid not exceed 9.5 per cent. For seeds stored at –5 and–10 °C with 9.6–12.5 per cent moisture content,the observed rate of decline of percentage normal seedlingswas adequately predicted by the viability equation, using theabove values for the constants. This suggests that for low moisturecontents the viability equation can be applied to estimate longevityat sub-zero temperatures. Lettuce, Lactuca sativa (L.), seed longevity, seed storage, viability constants, storage conditions     

Seed dispersal characteristics of Brassavola nodosa (Orchidaceae)

We used mathematical models for wind-dispersed seeds and wind-tunnel experiments to predict modal seed dispersal distance of the Neotropical orchid Brassavola nodosa under conditions approximating those found in its natural habitat: mangrove islands in Belize, Central America. Key variables in a simple ballistic model for predicting modal dispersal distance (xm) of an individual seed include: height of release (h); free-stream velocity (Uc); and terminal velocity of the seed (Ut): xm = h Uc/Ut. Modal dispersal distance of dust-like orchid seeds were predicted adequately by this ballistic model at low wind velocities and low release heights, but it underestimated the increasing importance of turbulence at higher wind velocities and greater release heights. We estimated the magnitude and relative importance of one measure of turbulence, vertical mixing velocity (W*), on xm in wind tunnel experiments. Our estimates of W* were within the same order of magnitude as those found for other small dust-like seeds and pollen. In high turbulence conditions, incorporation of vertical mixing velocity effects into the ballistic model of seed dispersal overestimated modal seed dispersal distances.     

十种菊科外来入侵种连萼瘦果风力传播的特性

借助风力传播连萼瘦果, 是菊科入侵种最普遍的自然扩散方式, 而其适应风力传播的特性与入侵性关系的研究还未得到足够的重视。阐明种子本身的风力传播特性与入侵潜力间的关系, 可以为深入理解外来入侵种的入侵机制以及入侵种的控制提供理论依据。该研究以10种菊科入侵种为研究对象, 测量其连萼瘦果的形态特征, 测定它们在静止空气中的垂直沉降速度和模拟风力条件下的水平扩散距离, 分析比较连萼瘦果的形态性状与沉降速度、水平扩散距离以及这些菊科入侵种在国内入侵范围的相关性。结果表明, 根据连萼瘦果的形态特征, 将这10个入侵种分为强、中和弱风传播3类; 连萼瘦果的重量和冠毛特征对垂直沉降速度和水平扩散距离均有显著影响, 对垂直沉降速度影响最大的因素是冠毛长度和冠毛上的小刺对数, 对水平扩散距离影响最大的因素是连萼瘦果的重量和冠毛长度。在垂直沉降速度和水平扩散距离间存在极显著负相关性(r = -0.806, p = 0.005), 表明沉降速度越慢, 借风力水平移动的距离越远。这些入侵种的发生程度与沉降速度间存在显著负相关性(r = -0.721, p = 0.019), 而与水平扩散距离之间存在着极显著正相关性(r = 0.927, p = 0.000), 说明水平扩散距离比垂直沉降速度更适合作为评估菊科入侵种入侵能力的指标。根据上述研究结果, 提出了南京市需重点防范胜红蓟(Agratum conyzoides)和牛膝菊(Galinsoga parviflora)等菊科入侵种的建议。     

影响黄帚橐吾种子生产的因素Ⅰ.生境和花序结构

 通过对黄帚橐吾(Ligularia virgaurea)自然种群在不同生境和种群密度下的种子生产的研究,结果显示：1）黄帚橐吾的种子生产无论是在种群水平,还是在总花序上同一部位头状花序水平,均受到生境条件的影响,其种子数量、种子均重和种子总重量等特征在不同生境间表现出沙地＞滩地＞坡地,在同一生境内则为高密度种群＞低密度种群和植被盖度较低＞植被盖度较高的趋势（滩地例外）;2）种子生产中的种子数量和种子总重与总花序大小、头状花序数量以及无性系株大小多呈显著正相关,与个体密度无关,但种子均重与上述因素（除无性系株大小外）的关系不显著;3）在总花序内不同部位头状花序间表现出的种子生产变化趋势（顶部＞基部）不受生境条件、种群密度等因素的影响; 4）种子生产在总花序上所表现出的这种部位依赖性可能是由于不同部位头状花序间开花时序上的差异引起种子从母体获取资源上的不同所致。     

Gastrointestinal passage time of seeds ingested by captive Japanese martens <Emphasis Type="Italic">Martes melampus</Emphasis>

The time it takes for ingested seeds to pass through the gut of animals is an important aspect of endozoochorous seed dispersal because it influences seed dispersal distance. Variations in the physical characteristics of seeds, such as their weight, volume, and specific gravity, can affect their movement through the gastrointestinal system of a given animal. We conducted feeding experiments with captive Japanese martens, Martes melampus (n = 4), at Toyama Municipal Family Park Zoo, central Japan to examine the effects of the physical characteristics of seeds on their passage times. The mean (±SD) transit time, mean retention time, and time of last appearance of four different types of commercial seeds were 2.6 ± 0.3 h (range 0.6–5.4), 9.7 ± 1.1 h (3.8–17.3), and 23.8 ± 3.1 h (12.2–51.8), respectively. All of these values are greater than those found during previous experiments conducted with mustelids. Similar to previous studies, however, none of these passage time variables was correlated with the physical characteristics of seeds. Our results thus indicate that martens disperse seeds of different plant species, whose size, volume, and specific gravity all fall within the range of those used in the present study, from parent plants at similar distances.