The life-history characteristics of Cardiocrinum cordatum (Thunb.) Makino (Liliaceae) are described here. This is a unique monocarpic perennial herb of temperate broad-leaved deciduous forests in the Japanese Islands and adjacent Far East regions. New aerial shoots appear above ground in mid April to early May. Cardiocrinum cordatum comprises distinct growth stages, single-leaf and multiple-leaved rosette stages, and then a flowering stage with a large multiflowered inflorescence at the top of the stem. The flowering plants attain 0.7-2.0 m in height and bear several large cordate cauline leaves, and 2-15 laterally blooming, greenish white flowers, 12-18 cm in size, are borne at the top of the straight inflorescence. Cardiocrinum cordatum depends on two reproductive modes, sexual reproduction via seeds and vegetative reproduction forming a few to several bulblets at the base of mother bulbs. The flowers are furnished with large nectar glands at the base of corolla, and the amount of nectar secreted is very high; thus, many bumblebee species are attracted to the flowers. Each flower has 600-670 ovules and produces 393-531 seeds (average 410). The average seed-setting rate per flower is high at 65-79%. An exceedingly large number of seeds with 4-5 mm thin filmy wings are produced, attaining several thousand (800-6000) in number per plant. Individuals asexually formed have large oneleaf or multiple-leaves, and can bypass crucial small juvenile stages with high mortality. In addition, because mature plants die after sexually reproducing once, ramets asexually reproduced can use the large spaces that the mother plants occupied. Cardiocrinum cordatum (Thunb.) Makino (Liliaceae)Syn. Hemerocallis cordata Thunb.; Lilium cordatum (Thunb.) Koidz.; Lilium cordatum Thunb.; Lilium cordifolium Thunb.; Cardiocrinum cordatum (Thunb.) Makino var. glehni (Fr. Schm.) Hara; Lilium glehni Fr. Schm.; Lilium cordatum Thunb. var. glehni (Fr. Schm.) Woodcock. Geographical and ecological distributionCardiocrinum cordatum s. lat. (including var. glehni ) is a monocarpic perennial, which represents one of the most unique life-history characteristics found in temperate woodland environments (Kawano 1975). The geographic range of C. cordatum extends from Sakhalin, southern Kuriles, south to Hokkaido, Honshu and Kyushu of the Japanese islands (Kawano et al . 2004; Fig. 1). This species primarily grows on the forest floor of broad-leaved deciduous forests.

Reproductive systems are recognized as having a profound influence on the extent and structure of genetic variation in plant populations. To investigate the spatiotemporal variation in the reproductive modes (sexual and vegetative reproduction) and population genetic structures of a monocarpic perennial herb, Cardiocrinum cordatum (liliaceae), we selected a variety of habitats (e.g. large forested area including primeval forest, small fragmented secondary forest, and so on) around Sapporo City, Japan. We conducted breeding experiments, monitored the fate and growth of marked individuals for 3 years, and also analyzed the spatiotemporal genetic variation of flowering plants within the populations using allozyme variation. Plants emasculated prior to anthesis produced mature fruits in all populations examined. However, seed production was significantly lower in the small fragmented populations, possibly because of the low availability of pollinators and subsequent pollen limitation. In these fragmented populations, the mature flowering plants tended to be more dependent on vegetative reproduction for their recruitment, because they can only produce flowers once in their lifetime. Genetic diversity using samples from mature flowering plants in each population was lower in the small fragmented populations than in the large populations. In addition, although genotypic compositions in the fragmented populations were more or less similar during the 3 years of the study, the dominant genotypes changed temporally and spatially every year in the large populations. The present study demonstrated that the reproductive features of C. cordatum can be altered in various environmental conditions, such as habitat fragmentation, and these changes considerably affected the population genetic structures and vice versa.

Plants show many responses to herbivore damage caused by insects. We investigated the effect of the specialist leaf herbivore Luehdorfia puziloi on the performance of a deciduous forest understory perennial herb Asarum heterotropoides. We conducted artificial defoliation experiments with different levels of damage (0, 50 or 100% clipping) in the early growing period (flowering time: early May) and in the late growing period (when natural herbivory by L. puziloi larvae occurs: early June) in a natural population. Effects of the defoliation treatments on reproduction (seed-set ratio) of A. heterotropoides in the treated year and on survival and development of the plant in the subsequent year were investigated. Severe defoliation conducted in the early period resulted in less currentyear seed production and increased regression to a dormant or non-reproductive stage in the following year, which would reduce the probability of future flowering. In contrast, defoliation conducted in the late period had no effect on the reproduction, survival and development of A. heterotropoides. Similarly, we found no obvious correlation between the damaged leaf area during the later period and seed set. Our results show that the specialist herbivore L. puziloi did not influence the performance of A. heterotropoides by damaging the plant later in the season when it was tolerant of damage.

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