Phenology of 16 species of ferns in a subtropical forest of northeastern Taiwan

A knowledge of fern phenology promotes understanding of the biology and ecology of ferns. In this study, the phenology of 16 fern species in a subtropical broadleaf forest (N24°46′, E121°34′) in northeastern Taiwan was monitored from August 1997 to August 2001. Every fern produced both fertile and sterile leaves in each year of the study. Most fertile leaves emerged in February and March, whereas most sterile leaves emerged from May to September. Most leaves reached full expansion during April–July and died during April–August. The average life span of leaves ranged from 4.4 months to 30.3 months. In seven species, fertile leaves lived longer than sterile leaves, but this difference was significant only in Pteris wallichiana. In the other nine species, sterile leaves lived longer than fertile leaves, but the difference was significant only in Cyathea spinulosa, Plagiogyria dunnii, and Plagiogyria adanata. The ephemeral fertile leaves of the two dimorphic species died soon after releasing their spores, at only 5 months of age. However, their sterile leaves survived for over 22 months. The fertile leaves of the other 14 species remained green for almost 2 years after releasing their spores. Sterile leaves remained sterile throughout their lives. Spores matured in May–July and were released in June–August. After spore release, the sporangia detached. No leaf produced a second cohort of sori. Several phenological events, including sterile leaf emergence, leaf expansion and senescence, and spore maturation and release, were significantly positively correlated with temperature but not with precipitation, whereas the emergence of fertile leaves was weakly negatively correlated with temperature and precipitation. However, those correlations varied among different species. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Phenological studies of selected leaf and plant traits of Didymochlaena truncatula (Dryopteridaceae) in a Brazilian submontane tropical rainforest

The phenology of the herbaceous fern Didymochlaena truncatula in a Brazilian submontane tropical rainforest is described. A total of 23 individuals were observed over 18 months (May 2012 to October 2013). The number of live leaves, leaf production, leaf mortality, leaf growth, and fertility were recorded monthly and correlated with local rainfall and temperature. The D. truncatula plants remained evergreen with a monthly mean of 6.49 ± 0.75 leaves that were produced almost continuously at a rate of 6.13 ± 1.46 leaves plant^?1 year^?1. This rate was higher than the leaf mortality rate, which was 4.61 ± 1.27 leaves plant^?1 year^?1. Monthly leaf growth of the population was correlated with rainfall. Leaf expansion was fastest in the first month after emergence (1.31 ± 1.03 cm day^?1). Fertility and leaf production intensity were not correlated with climate factors or seasonal variations. However, leaf mortality was negatively correlated with rainfall, causing variations in the number of leaves throughout the year. These results show that the phenological rhythms of D. truncatula were not equally influenced by climate variations. The phenology of D. truncatula corresponds to the phenology of a small number of aseasonal tropical ferns.     

Asphodelus aestivus,an example of synchronization with the climate periodicity

The phenology ofAsphodelus aestivus Brot. is described by means of a phenological model which has been formulated to fit skewed phenological data. Based on the model parameters the timing of different phenophases of biomass accumulation were determined. The biomass oscillations of leaves, inflorescence stalks and tubers were found to be synchronized with the predictable seasonal climatic changes. In addition, the plant seems to respond to minor random climatic variations. The emergence of leaves and inflorescence stalks depends on stored material in the tubers while leaf and inflorescence stalk elongation as well as flowering depends on current production. The storage part of the tubers seems to be a regulating structure, which is responsible for the synchronization ofA. aestivus productivity with the seasonality of the Mediterranean climate.A. aestivus is considered to be a Competitor Ruderal and Stress tolerant (C-R-S) strategist which may explain the wide distribution of this plant over the Mediterranean Basin.     

Phenological and growth patterns of the Mediterranean oak Quercus suber L.

The phenology of Quercus suber L., a dominant species of the montados in the Iberian Peninsula, was studied for 2 years in southwest Portugal. The seasonal progression of phenological events was analyzed in seven trees. Selected branches were examined monthly for shoot elongation, leaf number, branching, flowering, and fruiting. Radial stem growth and specific leaf weight were also studied. Active growth was observed from early spring to early summer. Reserves accumulated during winter and high photosynthetic activity in early spring apparently supported this strong development. The growth flush started with stem radial increment, which seemed to be impaired by spring rainfall. Male inflorescence production was the next phenological event. Old leaves were shed during new twig and leaf emergence. Shoot elongation and the number of new leaves produced were well correlated with the previous-year shoot's length, and were not clearly related to climatic factors. Radial growth resumed in autumn at a lower rate than in the previous spring, a possible consequence of a reserve depletion due to lower photosynthetic production in summer and investment on fruit maturation, which was complete by late autumn. Premature and excessive new leaf production were apparently subjected to self-pruning strategies related to the development of each tree's crown. Younger cork-oaks produced shorter and fewer shoots per module, and more sclerophyllous leaves than the older ones. A high intra-specific variability was observed in all the results.     

Exploring the causes of variation in phenology and morphology in Mediterranean geophytes: a genus-wide study of Cyclamen

The phenology and morphology of Mediterranean plants are constrained by drought in summer and cold temperatures in winter. In this study we examine how climatic factors and phylogenetic constraints have shaped variation in the phenology and morphology of 17 species of the genus Cyclamen cultivated in uniform garden conditions. We quantify the extent to which traits differ among subgenera and thus represent conserved traits within evolutionary lineages. We also explore whether leaf, flowering and seed-release phenology are correlated among species, and thus whether variation in flowering phenology results from selection on dispersal phenology. Our results show a significant influence of subgenus membership on leaf and flowering phenology but not on morphological traits or the timing of seed release. Among-species variation in foliage height, leaf size and seed mass (but not in floral traits) is correlated with chromosome number. Leaf traits show that species with a shorter vegetative period have a higher capacity for resource acquisition. Major phenological shifts, i.e. spring vs. autumn flowering and a decoupling of leaf and flower phenology in autumnal flowering species, thus occurred prior to the diversification of species in each subgenus and not as a response to selection on dispersal timing. Leaf and flowering phenology illustrate a gradient of strategies from autumn flowering in the absence of leaves (hysteranthous species) to spring flowering with fully developed foliage (synanthous species). In the former, flowering is uncoupled from resource acquisition by simultaneous photosynthesis, indicative that hysteranthy is a response to temporal unpredictability in the onset of rain after the summer drought. Our results support the idea that whereas leaf development is controlled primarily by moisture availability and secondarily by temperature, flowering is temperature dependent, above a minimum moisture threshold. © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society, 2004, 145 , 469–484.     

The photosynthetic performance of sterile and fertile sporophytes in a natural population of the fern Dryopteris affinis

We studied the photosynthetic performance of sterile and fertile sporophytes in a natural population of the fern Dryopteris affinis growing within a riparian forest (Central Italy) using chlorophyll (Chl) a fluorescence transients, the OJIP phase, where O is for the minimum fluorescence, P is for the peak (the maximum), and J and I are inflections. The “vitality” of the samples was assessed by the maximum quantum yield of primary photochemistry obtained indirectly from the fluorescence data (F_v/F_m); in the same way, the so-called performance index (PI_ABS) was obtained from fluorescence data. The photosynthetic performance (inferred from PI_ABS) of D. affinis changed significantly with the seasonal development of the fronds. The highest photosynthetic performance was recorded in the summer, corresponding to the period of spore release. The photosynthetic performance decreased in the winter, down to the minimal values of senescent fronds reached at the end of the seasonal cycle (May-June). On the whole, during the seasonal development, sterile and fertile fronds had a similar photosynthetic behaviour, as inferred from fluorescence data. At the end of spore maturation and dispersal (September-October), the fertile fronds showed somewhat lower photosynthetic performance than the sterile fronds, as revealed by PI_ABS. Being a long-lived fern, confined to humid and undisturbed sites in the Mediterranean, D. affinis deserves to be further investigated as a potential indicator of ecological continuity in Mediterranean riparian forests.     

Convergence in leaf phenology traits of two understory ferns in the northwestern Iberian Peninsula

Aims Plants control leaf phenology to maximize annual photosynthetic product. Although ferns play an important ecological role in many habitats, especially forests, their phenology traits have been poorly studied. Here, we investigate the leaf phenology of two ferns of the forest understorey and analyse the relationship between the timing of leaf emergence and spore dispersal and the effect of between-year climatic variation.Methods We compared the leafing and sporing phenologies of two ferns with very large (>2 m), overwintering leaves: Culcita macrocarpa and Woodwardia radicans. We regularly monitored individuals of six populations in the northwestern Iberian Peninsula during a 3-year study. We studied eight phenology variables: leafing start date, leafing end date, leaf expansion time, number of new leaves per individual, between-individual synchrony, within-individual synchrony, percentage of fertile leaves and spore release date. We also determined leaf mass per area (LMA) and gathered data on air temperature and humidity.Important findings Both C. macrocarpa and W. radicans produce few leaves (~2 leaves individual^-1 year^-1), which expand simultaneously for a very long period (from midwinter to early summer), are retained for more than 1 year (37 and 19 months, respectively) and have relatively high LMAs. Such traits, together with large leaf size, have also been found in seed plants from the forest understorey and represent adaptations to this light-limited environment. Spores of both study ferns are simultaneously released in late winter, with little between-year variation caused by differences in air humidity. This remarkable similarity between species suggests that the convergence in timing of leaf emergence favours the convergence in timing of spore dispersal.     

Phenology and abundance in relation to climatic variation in a sub-arctic insect herbivore–mountain birch system

The two forest-defoliating geometrid moth species Operophtera brumata and Epirrita autumnata are known to exhibit different altitudinal distribution patterns in northern birch forests. One possible explanation for this is that altitudinal climatic variation differentially affects the performance of two species through mismatching larval and host plant phenology. We explored this hypothesis by investigating the relationship between larval phenology and leaf phenology of Betula pubescens, which is the main host plant of both moth species, along ten replicate altitudinal transects during two springs with contrasting climate in northern Norway. There was a distinct monotonous cline in host plant phenology with increasing altitude in both years of the study, but the development of the leaves were generally 14 days later in the first of the 2 years due to cold spring weather. We found that larval development of both species closely tracked host plant leaf phenology independent of altitude and year. However, at the time of sampling, E. autumnata was approximately one instar ahead of O. brumata at all altitudes, probably reflecting that E. autumnata has faster early instar growth than O. brumata. The abundance of O. brumata was lowest at the altitudinal forest-line, while E. autumnata was lowest near sea level. Our results do not indicate that the altitudinal distribution patterns of the two moth species is due to any phenological mismatch between larval and host plant phenology. We suggest rather that natural enemies at low altitudes limit larval survival and thus abundance of E. autumnata, while an early onset of winter at the forest limit reduces survival of late eclosing adults of O. brumata.     

拔节期干旱和复水对春玉米物候的影响及其生理生态机制

物候不仅是气候变化的指示指标,也是作物模型的关键参数。现有研究主要关注物候变化与气候环境因子的关系,关于植物物候变化的生理生态机制研究很少。基于春玉米拔节期干旱与不同时间(抽雄期和吐丝期)复水的田间模拟试验分析表明:(1)不同时间复水均使灌浆期延长,乳熟期推迟(9d),表明物候对前期水分胁迫存在记忆。(2)干旱条件下叶片净光合速率(P_n)、蒸腾速率(T_r)、气孔导度(G_s)和相对叶绿素含量(SPAD)均随物候进程呈先降后升再降趋势,且均在抽雄期达到极小值;不同时间复水均使P_n、T_r和G_s在吐丝期达到极大值,而SPAD则在灌浆期达到极大值;叶水势(LWP)随干旱进程整体呈下降趋势,不同时间复水均只是减缓了其下降速度,表明LWP可用于描述物候对前期水分胁迫的记忆。(3)通径分析和决策系数分析表明,P_n是最主要的物候影响因子,而影响LWP的土壤相对湿度(RSWC)则是物候的主要控制因子,物候的变化是由P_n的累积变化引起...     

胡杨枝芽生长特征及其展叶物候特征

以5个不同发育阶段的胡杨(Populus euphratica Oliv.)个体为研究对象,观测记录了枝芽展叶物候、枝芽生长特征和叶形变化的空间分布规律。结果表明:不同发育阶段的胡杨个体以及同一个体树冠的不同层次,其枝芽生长及其展叶物候期表现出不同的时空特征。随着树龄的增加和树冠层次的增高(由基向顶),当年新生枝条长度、枝条叶片数和叶形指数逐渐减小,但叶面积和叶片干重逐渐增大。5个不同发育阶段胡杨个体均表现出展叶物候始于树冠顶层,依次向下结束于树冠基部;展叶物候期共性表现在枝芽萌动期均在4月上旬,起始展叶期集中在4月中旬,展叶终期则在5月上旬到下旬;树龄较大的个体其枝芽萌动期、起始展叶期、展叶终期较树龄较小的个体早;其枝芽萌动期到展叶终期的时间进程较树龄较小的个体短;不同发育阶段的个体枝芽萌动期出现的时间较为离散,起始展叶期和展叶终期出现的时间较为集中。相关分析表明,出叶周期与枝条长度、枝条叶片数量和叶形指数呈极显著正相关,与叶面积和叶片干重呈显著负相关。     

Climatic effects and phenological mismatch in cuckoo–host interactions: a role for host phenotypic plasticity in laying date?

Climatic effects on breeding phenology vary across organisms and therefore might promote a phenological mismatch in ecologically interacting species, including those engaged in coevolutionary interactions such as brood parasites and their hosts. Recent studies suggest that climatic induced changes in migration phenology may have mismatched cuckoos and their hosts in Europe. However, it is currently unknown whether cuckoo–host phenological mismatch results from different degrees of phenotypic plasticity or to different speeds of microevolutionary processes affecting hosts and parasites. Here we performed 1) cross‐sectional correlations between climate conditions and population level of phenological mismatch between the migratory brood parasite great spotted cuckoo Clamator glandarius and its main resident host in Europe, the magpie Pica pica; and 2) a longitudinal analysis to study within‐individual variation in breeding phenology for individual hosts experiencing different climate conditions over a period of nine years (2005–2013). Cross‐sectional analyses revealed independent and contrary effects of winter and spring temperature on magpie phenology: magpie hosts tend to breed earlier those years with lower February temperatures, however, high temperature in the first half of April spur individuals to lay eggs. Breeding phenology of cuckoos was tuned to that of their magpie host in time and duration. However, annual phenological mismatch between cuckoos and magpie hosts increased with NAO index and January temperature. Longitudinal analyses revealed high individual consistency in magpie host phenology, but a low influence of climate, suggesting that the climatic‐driven phenological mismatch between cuckoos and magpies at the population‐level cannot be explained by a host plastic response to climatic conditions.     

Greater temperature sensitivity of plant phenology at colder sites: implications for convergence across northern latitudes

Warmer temperatures are accelerating the phenology of organisms around the world. Temperature sensitivity of phenology might be greater in colder, higher latitude sites than in warmer regions, in part because small changes in temperature constitute greater relative changes in thermal balance at colder sites. To test this hypothesis, we examined up to 20 years of phenology data for 47 tundra plant species at 18 high‐latitude sites along a climatic gradient. Across all species, the timing of leaf emergence and flowering was more sensitive to a given increase in summer temperature at colder than warmer high‐latitude locations. A similar pattern was seen over time for the flowering phenology of a widespread species, Cassiope tetragona. These are among the first results highlighting differential phenological responses of plants across a climatic gradient and suggest the possibility of convergence in flowering times and therefore an increase in gene flow across latitudes as the climate warms.     

Cambial activity and annual rhythm of xylem production of elephant apple tree (<Emphasis Type="Italic">Dillenia indica</Emphasis> Linn.) in relation to phenology and climatic factor growing in sub-tropical wet forest of northeast India

The interrelationship between phenological events, climatic factors, periodicity of cambial activity and seasonal production of xylem was examined in Dillenia indica L. (Dilleniaceae) growing in sub-tropical wet forest of Meghalaya state, India. The reactivation of cambial activity was seen in the first week of May, 15 days after sprouting of new leaves and buds. The activity of cambium and xylem production gradually declined toward December and ceased from January to April end. There was correlation between leaf fall and cambial dormancy. It was evident from the correlation and regression analysis, the relationship between cambial activity, xylem production with climatic factors, the monthly mean minimum temperature plays an important role for the cambial activity and xylem production rather than influence by rainfall and relative humidity in D. indica L. The data were discussed in the light of cambial activity, xylem production and phenological events.     

Plant phenology-mediated indirect effects: The gall midge opens the phenological window wider for a leaf beetle

We examined whether larvae of the gall midge Rabdophaga rigidae (Diptera: Cecidomyiidae) can modify the seasonal dynamics of the density of a leaf beetle, Plagiodera versicolora (Coleoptera: Chrysomelidae), by modifying the leaf flushing phenology of its host willow species, Salix serissaefolia and Salix eriocarpa (Salicaceae). To test this, we conducted field observations and a laboratory experiment. The field observations demonstrated that the leaf flushing phenology of the willows and the seasonal dynamics of the beetle density differed between shoots with stem galls and shoots without them. On galled shoots of both willow species, secondary shoot growth and secondary leaf production were promoted; consequently, leaf production showed a bimodal pattern and leaf production periods were 1 to 2 months longer than on non‐galled shoots. The adult beetle density on galled shoots was thus enhanced late in the season, and was found to change seasonally, synchronizing with the production of new leaves on the host willow species. From the results of our laboratory experiment, we attributed this synchrony between adult beetle density and willow leaf flush to beetles’ preference to eat new leaves rather than old. Indeed, beetles consumed five times more of the young leaves when they were fed both young and old leaves. These results indicate that stem galls indirectly enhance the adult beetle density by enhancing food quality and quantity late in the beetle‐feeding season. We therefore conclude that midge galls widen the phenological window for leaf beetles by extending the willows’ leaf flush periods.     

Phenological comparison between two co-occurring Mediterranean woody species differing in growth form

Halimium atriplicifolium and Thymus vulgaris are two Mediterranean woody species, which differ in growth form and may co-occur under the same climatic constraints. Both possess distinct short (SS) and long shoots (LS). The aims of this work were: (1) to compare their phenological patterns, (2) to relate plant phenology with root depth and summer water potential, and (3) to compare the structure and phenology of SS and LS. Pre-dawn and mid-day shoot water potentials (Ψ_pd and Ψ_md) were assessed at the beginning and at the end of the driest period. SS and LS growth, flowering and fruit setting was followed every month throughout the annual cycle. Leaf shedding was followed with litter traps and leaf demography were monitored separately in SS and LS. Ψ_pd and Ψ_md exhibited a sharper drop in T. vulgaris than in H. atriplicifolium along the summer. Root depth of H. atriplicifolium was more than twice T. vulgaris. Phenophases of H. atriplicifolium occurred between spring and summer, while those of T. vulgaris concentrated in spring. The latter species shed many current-year leaves in September, probably in response to water shortage. In both species, LS growth occurred during a more rainy period than SS growth and during a warmer period in H. atriplicifolium. Leaf area and leaf mass per area were smaller for SS leaves than LS, probably due to water and carbon shortage at the time of SS growth. In conclusion, T. vulgaris suffered from more severe water stress than H. atriplicifilium due to its shallower root system and arrested phenological activity earlier in the summer. The different morphological and phenological traits of LS and SS suggest a specialisation in carbon gain along different time periods of the year.     

It is about time: genetic variation in the timing of leaf‐litter inputs influences aquatic ecosystems

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Scaling phenology from the local to the regional level: advances from species‐specific phenological models

Plant phenology, the study of seasonal plant activity driven by environmental factors, has found a renewal in the context of global climate change. Phenological events, such as leaf unfolding, exert strong control over seasonal exchanges of matter and energy between the land surface and the atmosphere. Phenological models that simulate the start of the growing season should be efficient tools to predict vegetation responses to climatic changes and related changes in energy balance. Species‐specific phenological models developed in the eighties have not been used for global‐scale predictions because their predictions were inaccurate in external conditions. Recent advances in phenology modelling at the species level suggest that prediction at a large scale may now be possible. In the present study, we tested the performance of species‐specific phenological models in time and space, looking at their ability (i) to predict regional phenology when previously fitted at a local scale, and (ii) to predict phenological trends, linked to climate changes, observed over a long‐term. For that task we used an historical phenological dataset from Ohio from the late ninetieth century and an airborne pollen dataset from Ontario, Québec and Maryland from the late twentieth century. The results show that the species‐specific phenological models used in this study were able to predict regional phenology even though they were fitted locally. The reconstruction of a phenological time series over the twentieth century showed a significant advancement of 0.2 days per year in the date of flowering of Ulmus americana, but very weak trends for Fraxinus americana and Quercus velutina.     

Does irrigation affect leaf phenology in deciduous and evergreen trees of the savannas of northern Australia?

Abstract Soil moisture was augmented experimentally during two successive dry seasons and the intervening wet season in a humid tropical savanna in Darwin, northern Australia. Leaf phenology was monitored in four common tree species Termmalia ferdinandiana and Planchonia careya (both deciduous species), and Eucalyptus miniata and Eucalyptus tetrodonta (both evergreen species). Irrigation produced consistently significant effects in only T. ferdinandiana. In this species leaf-flush was significantly earlier, canopy decline and leaf-fall were significantly later and the attainment of full canopy was earlier in irrigated compared with non-irrigated trees. Litterfall, and the seasonal patterns of contraction and expansion of stems (a measure of stem water status or storage) were not significantly affected by irrigation in any species. Leaf longevity in the deciduous species was 6–8 months; some eucalypt leaves lived for approximately 1 year, but none lived longer than 18 months. Irrigation had relatively little effect on leaf longevity. While variation in soil moisture is a potentially important cue to both leaf-fall and leaf-flush, stem water status and climatic factors such as vapour pressure deficit may also be important climatic cues to phenological behaviour.     

Multiplicity of biochemical factors determining quality of growing birch leaves

Due to rapidly changing physical and biochemical characteristics of growing leaves, correlations between traits of foliage biochemistry and the performance indices of flush feeding herbivores may vary considerably following relatively minor changes in experimental conditions. We examined the effects of the seasonal and inter-tree variation of a comprehensive array of biochemical compounds on the success of an early season geometrid, Epirrita autumnata, feeding on maturing foliage of mountain birch, Betula pubescens ssp. czerepanovii. We monitored the concentrations of individual phenolics, sugars, total nitrogen, nitrogen of proteins, and nitrogen of soluble compounds, water and acetone-insoluble residue. Simultaneously we recorded larval consumption, physiological performance, growth, and pupal mass of E. autumnata. We found significant phenological changes in almost all leaf traits measured. In bioassays with half-grown leaves, leaf gallotannin concentrations showed a nonlinear effect: in trees with high foliar gallotannin concentrations (over 10 mg g⁻¹), physiological performance was strongly reduced by high gallotannin concentrations. In trees with lower gallotannin concentrations, on the other hand, larval growth was reduced by soluble proanthocyanidins, not gallotannins. Differences between high and low gallotannin trees largely depended on phenology, i.e., on the age of leaves. However, not all the differences in leaf traits between late (with high gallotannin concentrations at the time of the bioassay) and early flushing trees disappeared with leaf maturation, indicating that there is also phenology-independent variance in the tree population. In the full-grown leaves of all the study trees, low concentrations of water and of nitrogen of proteins (but not nitrogen of soluble compounds) were the main factors reducing pupal masses of E. autumnata, while neither gallotannin nor proanthocyanidins now played a significant role. The observed change in the factors underlying leaf quality (from gallotannins and proanthocyanidins to nitrogen and water) relate to the activity of the shikimate pathway and the formation of cell walls: gallotannins and proanthocyanidins are both produced in the pathway, and these tannins are assumed to contribute – via binding into cell walls – to tough and durable cell walls. Interestingly, low quality of leaves did not automatically translate into low foliar consumption (i.e., benefits to the tree). On the trees with young, high gallotannin leaves, larvae actually increased consumption on low quality foliage. In the group of trees with slightly more developed, low gallotannin leaves, the quality of leaves did not clearly modify amounts consumed. In full-grown leaves, low leaf quality strongly reduced leaf consumption. These results emphasize the strong influence of tree phenology on the relationships between biochemical compounds and the herbivore. Received: 30 November 1998 / Accepted: 1 March 1999     

New geographic distribution records and assumed microcyclic life cycle of Triphragmiopsis jeffersoniae (Pucciniales)

Triphragmiopsis jeffersoniae was found on Jeffersonia dubia in Sapporo, Japan, in 2003. This was the first geographic distribution record of the fungus out of its native distribution range in continental Far East Asia. This fungus was found also in Nikko, Japan, in 2011. Triphragmiopsis jeffersoniae formed Aecidium-type sori and tripartite teliospores subtended by a pedicel. In the early spring, the fungus formed telia with or without Aecidium-type sori on petioles of emerging host leaves. Subsequently clusters of Aecidium-type sori were formed on the abaxial leaf surface. These sori did not repeat; but they were soon densely surrounded by telia. Both the Aecidium-type sori and telia were densely crowded and no small isolated telia were formed. The assumption that the spores from Aecidium-type sori do not have infective ability was confirmed by inoculation experiments and microscopic observations for the Japanese materials. The Aecidium-type spore germlings failed to invade the Jeffersonia leaf either directly or through a stoma under the experimental conditions. Thus, T. jeffersoniae was assumed to have microcyclic life cycle, comprising the functional teliospores and the non-functional Aecidium-type aeciospores.