In 1946,LYSENKO stressed the importance of hill-planting in agricultural practice, and stated that Kok-saghyz (Taraxacum kok-saghyz RODIN) plant produced several times more yield of root when planted in hills than when the same amount of seed was evenly distributed over the field. Much has so far been said of the advantage of hill-planting by Japanese investigators, but there are as yet little evidences that may lead・to a rea・sonable conclusion. Two experiments were carried out in 1954 and 1955 with radish and soybean to investigate the effect of hill-planting and the number of plants per hill on the yield of these crops (Figs. 1 and 2). The results showed that the yield per area (y) was solely determined by the plant density or the number of plants per area (ρ) whether they were grown singly or in hills of various sizes. So far as the density remained constant, the plants always yielded approximately the same amount of crops per area as given by the Yield-Density Effect formula, yρ^<α-1>=K (KIRA et al. 1953), irrespective of the mode of planting. It was suggested that the plants closely standing together in a hill may have the advantage over isolated individuals in their resistibility to certain unfavorable conditions such as the severe competition with weeds. This may result in higher per cent survival of initially planted individuals which in turn may increase the final yield.
In spite of an intimate relationship between men and domestic cats during thousands of years, there are yet numerous obscurities on the latter's life modes. The present paper deals with the results of a small census on their home range taken during 1954-1956 at Shinkotoni, a semirural village in the suburbs of Sapporo City. Answers of primary school children against enquetes on the maximal roaming distance of cats reared in each home (1), and of those visiting each home (2) are summed up in Table 1,which suggests 1) a marked variability of home range from 0 to more than 150 m (in an extreme case, 1 km), 2) relatively short roaming distance in comparison with their locomotive activities and 3) a slight tendency of the wider home range in males than in females. Furthermore, to obtain a more closer picture of home-range mosaics, the interviewing method was undertaken at two districts with the results illustrated in Figs. 1-3. The roaming distance shows again a marked individual variability, with the occurrence of a few cats whose home range extends over relatively wide areas. It was mainly these individuals that show a marked aggressiveness towards other cats.
1. Twelve kinds of annual weeds were selected to clarify the autecological characters of weeds in the fields cultivated in 1956. These weeds were planted on porcelaine germinating dishes every other month since May, and the differences of the following six stages were observed : budding stage, seedling stage, vegetating stage, flowering stage, fruiting stage and withering stage. 2. The results of these germinating tests are as follows : 1) The weeds which germinated in the early season, were remarkable in the growth of their leaves and stalks in the growth stage, and those which germinated a month later than the former were distinguishably slow in their growth, their branching and tillering declined and they became gradually dwarfed. 2) The earlier the seeds germinated, the longer their flowering period became. 3) The later the seeds germinated, the lewer the seeds were produced, depending upon the growth, branching and tillering. 3. Most of the seedlings which sprouted after August flowered, but their seeds did not ripen fully. Seedlings which sprouted after September stopped growing and most of them died in the middle of October owing to the frost. 4. From the results of the observations mentioned above, the writer is of opinion that the amount of seeds of the annual weeds sprouting after August is extremely small in Hokkaido, and the cultivating fields are not greatly influenced by the weeds sprouting after August.
1. Ten individuals, 5 males and 5 females, were marked and numbered consecutively. No. 1 Male and No. 2 Female were about 3.5 years old, Nos. 3 and 4 Females about 2 years, Nos. 5 and 6 Females about 1 year, and Nos. 7,8,9 and 10 Males 4 or 5 months. They were divided into five combinations of the same aged individuals and preliminarily reared in five small cages for about two weeks. 2. No. 1 Male dominated No. 2 Female through his superior pecking, and then the relation developed into mating and the female laid two eggs. Both of No. 3 and No. 4 Females laid eggs though they were in a homosexual combination of females, while Nos. 4 and 5 Females laid no eggs under the same conditions. But in the two combinations, Nos. 3 and 5 Females dominated respectively thier mates, Nos. 4 and 6 Females, by pecking them away from food dishes at their feeding time. In combinations of Nos. 7 and 8 Males, and Nos. 9 and 10 Males, as well as of Nos. 7 and 10,and Nos. 8 and 9,there could hardly be found no dominance-subordination relationship, though they vigorously pecked each other at their feeding time. The two individuals of the combinations except that of No. 1 Male and No. 2 Female, however, took up their positions on either side of the small cage almost all day long. 3. The preliminary observation of these combinations gave us a promising opening for further approaches. Namely, we could find it most practical and appropriate to begin our observations with such a flock as of the four youngest males set free in a pigeon pen, and thereafter proceeded with our research, gradually joining the remaining combinations, one by one, in this original flock. 4. These starting individuals, Nos. 7,8,9 and 10 Males, neither encountered to fight nor behaved themselves in such manners as to affect their mutual relation. Moreover, they did not peck one another at all at their feeding time, in contrast with the combinations of them kept in the preliminary small cages. It must be remembered, however, that their food dish was about six times as large as those from which the combinations had been fed. They took a recess together on the upper perch, and fed in flocks showing warning behaviors on the floor. None of them occupied its own definite position on the perch, and they usually kept a certain space between them. When by changce one happened to be too close to another, a mutual pecking took place between them, which might make them keep a sufficient or one of them flew away so as not to be pecked any more. Soon after Nos. 5 and 6 Females joined this flock, a new fact was found that No. 8 Male pursued more actively No. 5 Famale, which usually avoided him, than No. 10 Male did. 5. Since these ten individuals were all set free in the pigeon pen, their movement on the floor became more active than it had been in the smaller flock, though they spent most of their time on the perches. No. 1 Male commenced displaying against every other male or female, which used to be avoided by the latter. Five females, Nos. 2,3,4,5 and 6,tried to make a billing one after another with No. 1 Male, and often succeeded in copulation after billing. Other males, Nos. 7,8,9,and 10,wandered sometimes with incomplete display, near those females, and after a while No. 8 Male consorted himself with No. 3 Female. These relations developed on the floor, while their spacing was executed on each perch and the board. 6. The setting of artificial nests on the perches, however, made an abrupt transition to the most active display of males, by which they perhaps declared their nest-occupations. Thus No. 1 Male and No. 8 Male occupied their nests on either end of the upper perch, and divided the perch into their territories. Then Nos. 1 and 8 introduced Nos. 2 and 3 Females respectively into their own nests C and A, and drove away intruders by pecking or body-checking. Besides, No. 1 Male continued consorting relations with other females except with No. 3 Female only on the floor. Since Nos. 2 an
As to the distribution of the Chamaecyparis obtusa forest in Japan, KAWADA explained it by the precipitation throughout the year. Afterwards, MAEDA pointed out that the monthly rainfall in winter indicating about 100mm or more is suitable to the occurrence of this forest. At the same time, he also stated that the podosolization of soil is an index to the forest and is promoted not only by climate but also by topographic conditions and the character of the rock. In the present paper, the habitat condition of this forest in Shikoku is briefly discussed. The Chamaecyparis obtusa forest in middle Honshu was studied by MAEDA from the phytosociological point of view. But the forest in Shikoku has hitherto not been surveyed satisfactorily. In Shikoku, the Chamaecyparis forest is found as an edaphic climax within the area from the upper part of the warm-temperate forest region to the cool-temperate forest region. This forest usually occurs on a small scale on ridges, rocky outcrops, and steep slopes of mountains, while it often occupies extensive serpentine areas in the Fagus crenata climax region. As the result of the writer's vegetational survey, Rhodoreto-Chamaecyparidetum obtusae (Chamaecyparis obtusa-Rhododendron metternichii Ass.) is described here. The floristic composition and the structure of this association are presented in Table 1. This assoclation is different from the related ones in middle Honshu by such floristic elements as Rhododendron metternichii, Rh. reticulatum, Rh. weyrichii, Tritomodon cernuus var. rubens, Hugeria japonica var. ciliaris, Ilex rugosa var, stenophylla, Il. sugeroki va. longipedunculata, Parabenzoin trilobum, Viburnum urceolatum, and others. The Chamaecyparis obtusa forest on the Pacific side of the south-western half of Japan should be included in this association.
The experiments which form the basis of the present report were conducted along the same line as done by ALLEE and BOWEN (1932) on the fixation of poison by goldfish populations. The material (25-27 mm in-length) was obtained from a water duct in the field and used for experiments after rearing for a week in the laboratory. As an environmental poison colloidal silver was employed. Tap water used as the solvent contained 0.00001 mg/cc NH_3,0.00164 mg/cc of Cl, with a pH 7.4. Unless otherwise stated, all the following experiments were carried out under the temperature range between 15.5°-16℃. First, effects of the colloidal silver suspensoid upon an isolated fish were tested, using 5 units for each of the various concentrations shown in Table 1. The results (Table 2) were fairly fluctating, but the average showed rather reliable correlation between the colloidal silver consentration and the life duration (Fig. 1). According to the result, a 4.374 mg/cc concentration was adopted as a standard strength of the poison. In the chief experiments, 4 series of populations which were composed of 5,10,15 and 20 individuals respectively, each with 3 units, were subjected to a 200 cc of poison of the above mentioned concentration. The results, as set out in Fig. 2,clearly demonstrated that the greater the number of the fishes, the longer was their life duration. We then measured the quantities of the silver precipitated by each series of populations and obtained a result (Fig. 3) which showed that the fixation of silver per one fish was about 0.011 mg, with the exclusion of the exceptional result of the series consisting of 5 individuals. According to the examination of the fishes poisoned to death, it was made clear that the gills were heavily covered with the precipitated silver. Probably the death of the fishes, in addition to the chemical virulency by the suspended sliver, was accelerated by such a mechanical obstruction on the respiration. Further experiments concerning the temperature effects on the conditioning of the environmental poison indicated that a unit of 15 individuals exposed to 23℃ survied in an average much longer (162 min.) than the 5 control units (68 min.). In this case, it was also observed that at the temperature range between 16°-23℃, Q_<10>-rule could be applied to the increase in breathing number (108→190 per min., 10 min. after being exposed to the condition) and the decrease of the survival time (110→68 min.), while at a temperature of 13℃, this rule could not be proved true, for all the fishes in the virulent water lived even after 5 days when the experiment was stopped.
1. The River Yagi, the torrential part of the Maruyama River system, may be divided by its river form into two areas, namely upper and lower torrents. Benthic insect communities show two different types in accord with the river forms mentioned above. These are shown in Tables 1 and 2 as well as in Fig. 3. 2. Total standing crops of the main species are very different between the upper and lower torrential areas ; Stenopsycha griseipeknis (Trichoptera) may be responsible principally for this phenomenon. These are shown in Table 3.
The investigation of the epiphytic bryophyte community on the trunk of Shiia cuspidata MAKINO on the western side of Mt. Kamimata, about 140m. sea level, Tsudai-mura, Kochi Prefecture, Shikoku, is here reported by the writer. On the trunk of four sample trees there were found 41 species of Hepaticae and 12 species of Musci, Frequent species in this epiphytic bryophyte community are Lejeunea bon ensis, Metzgeria hamata, Pycnolejeunea obtusilobula, Brachiolejeunea sandvicensis, Ptychocoleus nipponicus, Frullania densiloba, Fr. truncatifolia, Fr. kagoshimensis, etc. The physiognomy of the epiphytic bryophyte community on Shiia cuspid ta MAKINO is characterized by the growth-form of the above mentioned species. The chief growth-form is of the Hardly pressed mat type (Hp). Epiphytic species can be divided into six distributional types by the vertical range and the value of frequency. Typical type of vertical distribution on the trunk of Shiia cuspidata MAKINO is Type E. This distributes from the lower part of the trunk to the upper crown and shows the greatest value of frequency at the crown base. Typical species of this type are Brachiolejeunea sandvicensis, Frullania densiloba and Ptychocoleus nipponicus.
It is generally reported that the yellow muscardine fungus, Isaria farinosa, is supposed to be the most important factor for environmental resistance against the overwintering rice stem borer, Chilo suppressalis. The writer attempted to make quantitative investigations on the relative effectiveness of the larvae to the controlling factors. Two heaps of rice plant straws in which overwintering larvae inhabited were used for study ; one was placed on a paddy field and the other in a barn. In the former heap, the yellow muscardine, which was prevalent in late spring or early summer, was found to be an important cause of the mortality of larvae, while those killed by hymenopterous parasites were almost as large in proportion. As for the heap in the barn the number of dead larvae caused by this fungus was much less than in the case of the former. Besides these two controlling factors, the dead larvae of which causative agent was not elucidated were considerably included in both heaps. Attention must be paid to the fact that the numbers of such dead larvae were no less than those by the yellow muscardine or hymenopterous parasites. Isaria infections were not found among the larvae feeding on the stem of the rice plant growing on a paddy field.
An investigation was made in the precincts of Kasuga shrine in Nara City to ascertain the floristic composition in relation to the environment of the epipetric plant community growing on Ishidoro (the stone-lantern pillars) there. 1. The epipetric plant communities found within the area are integrated into Hypneto-Hedwigietum with the following characteristic species ; Hedwigia albicans (WEB.) LINDB., Hypnum plumaeforme WILS., H. plumaeforme var. minus BROTH. and Grimmia pilifera PALIS. This plant-union consists of the following seven societies ; Cladonia gracilis var. chordalis society, Parmelia tincto ; uma soc., Hedwigia albicans soc., Hypnum plumaeforme soc., H. plumaeforme var. minus soc., Chrysocladium retrorsum soc. and Meteorium helmintocladulum society. 2. It may be considered that Hedwigia albicans soc., Hypnum plumaeforme soc. and H. plumaeforme var. minus soc. exhibit the features of the genuine-facies of the epipetric plant communities found in the area. The community dominated by Hedwigia alticans (WEB.) LINDB. shows better development in fairly sunny habitats, while that of Hypnum plumaeforme var. minus soc. does so in the shady habitats overhung by the crown of evergreen trees close by. 3. Cladonia gracilis var, chordalis soc. and Parmelia tinctorum soc. may be considered as facies which occur mostly in an open and sunny hibitat. The occurrence of Chrysocladium retrorsum soc. and Meteorium helmintocladulum soc. is confined to the most shady habitats where the trees are overshadowing all the time. 4. The degree of overshadowing by the trees nearby and the changes of environmental factors, such as, air temperature, saturation deficit and illumination, at five stonelantern pillars which were occupied by different communities, were respectively recorded on March 15,1956. From the obtained data, considerable differences of microclimatic factors, i. e. saturation deficit and illumination, are clearly observed among respective habitats according to the degree of overshadowing of the trees close by. It may be considered that the degree of overshadowing by the trees plays an important role on the development and the distribution of the epipetric plant community.
Two groups of opium poppy seeds (Papaver somniferum L.), vernalized at 2℃ for 20 and 10 days respectively, were seeded in conformity to the general method of culture, using as the control a non-treated one, in November 1955. 1) Vernalized plants responded well in the germination and the early growth. 2) As for the height of plants, the 20-day-treated group was tallest ; and the non-treated, lowest during the early stage of growth, but during the budding and flowering time, this order was completely reversed and was immutable until the harvesting season. 3) It is recognized that the 20-day-treated group flowered about 2 days earlier than the others, and there was practically no difference between the 10-day-treated and the non-treated groups. 4) The two experimental facts the flowering promotion observed by means of the vernalization at 2℃ and the success in flowering of non-treated seeds sown in the spring of 1956 suggest that the plant seems to pass through its vernalization phase at temperatures ranging from 2℃ to the prevailing temperature in spring. 5) The vernalization on opium poppy exerted a very noticeable influence upon the yield of opium, increasing the yield 24.0 percent in the 20-day-treated group, and 11.6 percent in the 10-day-treated one in comparison with the control.
I studied the fauna and flora of Kagamiike, a pond situated in front of the Daibutsuden, the Great-Budda-House, of Todaiji-Temple, Nara. The pond is inhabited by a number of Ischikauia steindackneri SAUVAGE, the fish, which is herbivorous and eats water plant. In the pond there is no water plant now, but we find on the bottom a thick layer of Aphanothece sp. The characteristics, which we recognized in the plankton community of this pond, are as follows : (1) The number of species is poor. (2) The annual fluctuation is small. (3) The dominant species remain almost always the same. Zooplanktonic dominant is Diaptomus japonicus and phytoplanktonic dominants are Melosira spp. (Fig. 3 shows the annual fluctuation of the calculated volume of each plankton species.) The micro-organisms in the bottom mud are shown in the table 3 ; the species are almost the same as those of phytoplankton.
It semes that the renovation of natural grassland with the pasture crops is one of the methods to increase the grassland production. The adaptation of grasses and legumes to any locality or region is determined by their tolerance as to competition with other plants. The purpose of the present paper is to investigate ecologically and agronomically an adaptability of the pasture crops at the roadside communities in our stock farm. Some fifty years ago, seeds from these pasture crops were sown by Japanese Army Horse Supply on our stock farm of Kawatabi, in Miyagi Pref. But these pasture crops are not cultivated in the present time. The results of the field survay and the cultivation tests are resumed as follows : the roadside communities is composed of species which are resistant to the influences of treading, trampling and of mowing. Eragrostis ferruginea, Plantago asiatica, Echinochloa Crus-galli and Zoisia japonica which occur in the zone of the most intense treading with high constancy. As the pasture crops, Orchard grass, white clover and red clover shows an increase in the same tendency of the wild plants mentioned above. Redtop and sweet scented vernal grass are not develops with the zonation, and they have common occurrence. In this community tall oat grass and timothy are rare or absent. On the other hand these pasture crops showed a high producing capacity in our experiment of cultivation. Ladino clover, crimson clover and Italian rye grass showed also a high producing capacity, but they were not found on the roadside. From these results, it becomes clear that most of the pasture crops escaping on the roadside communities have the high adaptability in this region.
Selon la comparaison de l'aire de repartition avec la position d'une ligne isotherme ou avec les valeurs climatologiques obtenues par la station meteorologique, de nombreux criteres ont ete construits par differents auteurs de la limite septentrionale a la foret toujours-verte au Japon. MAYR^<7)> et HONDA^<1)> ont choisi la valeur moyenne de temperature. KIRA^<2,3,4)>, et OTA^<8)> ont tache de trouver certaine valeur par temperature totalisee. D'apres la methode de RUBEL^<18)>, SUZUKI^<10)> et WADA^<13)> ont considere comme importante la duree des mois dont la temperature moyenne surpasse 10℃. Toutefois aucun de ces criteres ne peut conincider exactement avec la limite au nord de l'alliace du Shiion Sieboldi. Nous avons tache alors de mesurer les facteurs ecologiques et les fonctions vitales des plantes dominantes ou caracteristiques aux champs. Les donnees critiques ont ete obtenues chez une association individuelle a la limite septentrionale de cette alliance. Les observations aux champs, cependant, ne sont pas faciles a repeter comme au laboratoire. Donc il serait plutot rationnel de choisir un bois convenable a la premiere observation et ensuite de choisir un bois a l'aire extreme. Par comparaison des donnees obtenues de ces deuxobservations on peut rapisonablement distinguer les facteurs ecologiques qui limitent la repartition du groupement vegetal. Le bois de Susanoo est une association individuelle a Daphniphyllym Teijsnanni parmi l'aire de l'alliance du Shiion Sieboldi, ou on peut convenablement loger aux champs et apporter ou exporter les instruments dont on a besion. Les observations out ete faiter aux 22-23 decembre, 17-18 janvier, et 22-23 mars. Les moyennes quotidiennes de la valeur osmotique sont d'autant plus hautes que celles de la temperature sont plus basses, mais le cours de la courbe quotidienne montre le point du minimum a la nuit et celui du maximum a la journee. Donc ce n'est pas seulement la temperature pui limite la vie du Skiion Sieboldi en hiver. La valeur ainsi que la fluctuation est plus basse a l'espece sous le bois qu'a celle en couronne du bois. Au jour de pluie, la courbe de valeur osmotique descend, quand l'aire du racine est humide. Le point de compensation quotidienne apres H. WALTER est atteint bien matinalement, 2 ou 3 heures apres le soleil levant pour I'espece a la couronne du bois et pour celle sous le bois, juste apres le lever du soleil. Il ne semble pas que la respiration surpasses I'assimilation dans la foret tousjours-verte en hiver, mais il est encore necessaire a confirmer cette evidence dans l'association individuelle a la limite au nord.
Le rapport entre la vie et les etats environnants est un sujet da la premiere importance in ecologie. Au point de vue de la dimension du champ visuel, macroscopique ou microscopique, ou un investigateur observe l'ecosysteme, les diverses sections se distinguent dans cette science. La dimension I, le plus macroscopique, est celle qui est geobotanique. Les associations chionophiles dans le mont Gassan se trouvent exclusivement aux cotes sous le vent, parce que la neige est chasse sur cotes contre le vent et entasse sur celles sous le vent. Voici l'exposion orographique que determine l'existence des associations elle-memes, bienqu'elle puisse etre analysee aux facteurs plus menus. Les facteurs macroscopique, les types de la terre, l'especes influentes de faune, le genre de la culture humaine sont compris dans la dimension I. Un facteur geobotanique, peut etre analyse plus minutieusement dans la dimension II, ecoligique. L'exposition orographique, par exemple, est un facteur indirect, lorsqu'on le considera precisement. Elle est un sujet compris a laquelle sont reunises la temperature de la terre, la duree d'etre sous la nelge, la quantite d'eau dans la terre en floraison etc. Un facteur ecologique doit etre mesure aux champs, tandis qu'un facteur geobotanique peut etre souvent utilise par les donnees offertes par certains organes officiels. Dans la dimension II, l'association doit etre representee par l'espece dominante ou caracteristique, car l'observation des facteurs ecologiques doivent se tenir au petit nombre de stations dans une association. Dans la dimension III, le plus microscopique, le facteurs extremement simplifie est confronte avec une fontion physiologique separee. Ainsi les etats environnants ont ete analyses d'autant plus precisement qu'un facteur physiologique est meme aux champs qu'au laboratoire. La temperature de 20℃ a la dimension I est mesure dans la station meteorologique et ne represente pas necessairement l'etat du habitat. Celle-la a la dimension II doit etre mesuree aux champs, mais elle ne designe pas toujours l'etat dans lequel la fonction vegetale elle-meme se tient. Les etats du corps vegetal eux-memes dominent directement la fonction vitale : par exemple temperature des feuilles ou des racines, pression osmotique ou pH-valeur de la seve cellulaire etc. Ce sont les facteurs physiologiques. Chacune des trois dimensions, geobotanique, ecologique et physiologique, nous entraine egalement dans la route pour ecologie, mais cette science ne peut pas exister dans une dimension. L'avancement de la recherche d'une dimension nous stimulera necessairement a nous occuper d'une autre. Les sections de l'ecologie, de la synecolgie a l'autecologie, de la phytogeographie ecologique a la physiologie ecologique, de la l'ecologie descriptive a l'ecologie experimentale, n'ont pas de differences reelles, mais ce n'est qu'une difference de forme. Il y a peu d'ecologistes qui ont comme champs de recherche ces trois dimensions. Beaucoup s'occupent en general moins de deux dimensions. Si on ne peut en traiter de plus de deux, il serait indispensable qu'un ecologiste coopere avec un autre qui a son champ de recherche dans l'autre dimension, Si on ne peut traiter qu'une dimension meme dans un laboratoire le mieux installe, il deviendrait necessire que les trois ecoles cooperent a resoudre le probleme du rapport entre la neige et vegetation.