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1.
The karyotype and the C-banding pattern in two species ofHexastylis andAsarum epigynum were analysed in detail, and the results obtained were compared with those of the other species ofAsarum, Asiasarum andHeterotropa previously reported. The present results were partially different from the previous reports related to the karyotypes of these species. The karyotype observed in two species ofHexastylis (2n=26) was represented by ten pairs of metacentric chromosomes and three pairs of small subtelocentric chromosomes, which is very similar to that ofAsiasarum in eastern Asia. The C-banding patterns ofHexastylis andAsiasarum, however, were clearly different from each other. A striking difference was found in one of the three pairs of small subtelocentric chromosomes. A Formosan speciesAsarum epigynum had the somatic chromosome number 2n=12 and a highly asymmetrical karyotype composed of mainly subtelocentric chromosomes. These karyological features were remarkably different from those of the other groups inAsarum s.l.  相似文献   

2.
Both 4-lobed and 5-lobed disk flower corollas have been found in species ofCoreopsis. A brief survey of several manuals for portions of the eastern and southern United States indicated that the 4-lobed condition is relatively rare in Compositae. A survey of the North American species ofCoreopsis suggests that the character has high taxonomic significance in the genus.  相似文献   

3.
The new segmented spongeColospongia ramosa n. sp. is described from Carnian shallow-water limestones of the Western Carpathians (Aggtelekt Karst, Silica Nappe) of North Hungary. This new species occurs also in the Carnian part of the Pantokrator Limestones of Hydra island (Greece).Colospongia ramosa n. sp. differs from other species ofColospongia by the crescent-like chambers and by its branching growth.  相似文献   

4.
This report shows that one of the most important roles of the flower nectar of an autogamous perennialRorippa indica (L.) Hieron is as an attractant for employing some ant species as a defense against herbivorous insects. The plant has flowers from spring to early winter. Its flower nectar is frequently stolen by some ant species (hereafter cited as ants) which also feed on small herbivorous insects on the plant. Internations among the tritrophic levels (R. indica, herbivores, ants) were experimentally examined and the followings became clear. (1) Ants were attracted toR. indica in search of its flower nectar. (2) The gradual secretion of flower nectar seemed to detain ants on the plant. (3)Pieris butterfly lavae were the major herbivores onR. indica and were potentially harmful to the plant. (4) The presence of ants reduced the survival rate ofP. rapae larvae onR. indica. (5) The presence of ants reduced the feeding damage toR. indica. (6) The disadvantage of nectar use by ants seemed to be minimal for the plant since the ants did not disturb the other flower visitors. These facts suggest a mutualistic relationship betweenR. indica and ants. That is, the flower nectar serves as an indirect defense against herbivorous insects.  相似文献   

5.
Getulio Agostini 《Brittonia》1973,25(2):174-176
Cordia thaisiana is described as new from the state of Zulia, Venezuela. It can be distinguished from other species in the section by the inconspicuously nerved calyx, the flower disk fused with the ovary, and by the glabrous branches and leaf blades. A key is provided for the species ofCordia sect.Gerascanthus growing in northern South America.  相似文献   

6.
7.
Aesculus Xcarnea, originated in cultivation, is considered on morphological grounds to be a hybrid between the AmericanA. pavia and the EuropeanA. hippocastanum. The plant is rather fertile and breeds true from seed. Cytologically it is a tetraploid while all other species are diploid. Two dimensional Chromatographic separation of the phenolic compounds and characterization of spots were made on leaf and flower material of the three species concerned. Chromatograms of flower extracts strongly support the belief thatA. pavia is one of the parent species. Leaf chromatograms supportA. hippocastanum as the other parent species. Identification of the three major spots of leaves ofA. hippocastanum reveal them as quercetin-3-O-rhamnoside, quercetin-3-O-glucoside, and quercetin-3-O-arabinoside.  相似文献   

8.
Morphological, cytological, and paper Chromatographic studies of populations from northern Michigan and examination of herbarium specimens from throughout North America were used to clarify the relationships ofGoodyera oblongifolia, G. repens var.ophioides, andG. tesselata. A canonical analysis of morphological data from mixed populations of these three species depictsG. tesselata as intermediate betweenG. oblongifolia andG. repens var.ophioides. The latter two species are diploid (2n = 30) andG. tesselata is tetraploid (2n = 60). Triploids (2n = ca. 45) were found in two mixed-species populations in northern Michigan.Goodyera tesselata produces three phenolic compounds present inG. oblongifolia and five different compounds present inG. repens var.ophioides. The range ofG. tesselata is confined to glaciated territory (except for two stations) in northeastern North America where the postglacially produced ranges ofG. oblongifolia andG. repens var.ophioides overlap. However,G. tesselata is quite abundant in areas outside the region of sympatry of the other two species. Based on this evidence, it is postulated thatG. tesselata is an allotetraploid species which resulted from hybridization betweenG. oblongifolia andG. repens var.ophioides during early post-Pleistocene. The slightly earlier blooming season ofG. tesselata may have been selected for to provide a measure of reproductive isolation between the tetraploid and its parents and to adapt the new species to the rather short growing season of northeastern North America.  相似文献   

9.
The effect of various diets on nymphal development and survival of two predaceous anthocorid bugs,Orius albidipennis (Reuter) andO. laevigatus (Fieber) was investigated in the laboratory. Five different diets were compared: eggs ofEphestia kuehniella Zeller; eggs ofE. kuehniella plus mixed flower pollen; only mixed flower pollen; pollen from sweet pepper (Capsicum annuum L. cv. Mazurka) flowers; and sweet pepper plants. A high percentage of predators successfully completed nymphal development on those diets containing lepidopterous eggs. When fed on sweet pepper pollen, the survival percentages were 65% forO. laevigatus and 38% forO. albidipennis. No nymphs of either species completed the nymphal stage on mixed flower pollen or on sweet pepper plants. Development was significantly faster on diets containing eggs ofE. kuehniella. Results are discussed in relation to the capability of the bugs to survive periods of prey scarcity and to the optimization of release strategies for these predators in the greenhouse.  相似文献   

10.
This study examines the role of learning and memory in the butterflyPieris rapae crucivora Boisduval during foraging for flowers. In an outdoor cage with 6 flower species,P. rapae showed various visiting patterns: some visited only one species, while others visited several species in a day. The foraging process for flowers ofErigeron annuus (L.) Pers. could be divided into two successive steps: (1) landing on the nectaring caputs, and (2) finding the source of nectar in the caput. Butterflies learned to proceed through the two steps more efficiently with successive attempts: they gradually decreased landings on nectarless caputs and probings on the nectarless petals of ligulate flowers respectively. As a result, handling time per unit caputs became shorter, and apparent rewards per unit time, i.e. the efficiency of collecting nectar, increased. In addition, once learned,P. rapae could remember a rewarding flower color for 3 days, which was not interfered with by learning another flower color. This indicates thatP. rapae keeps memory for a period longer than 3 days, and that they can remember at least two flower species as suitable flower resources. Furthermore, data indicated that they sometimes can apply the foraging skills obtained on other flower species to a novel one. These abilities could enable butterflies to easily switch flower species, or to enhance labile preference. It has been known thatP. rapae also shows flower constancy, which may be due to memory constraints. Therefore, they may appropriately use two foraging tactics: visit consistency and labile preference, to get enough nectar according to their circumstances.  相似文献   

11.
Recognition ofClematis gattingeri Small as an independent species has been based primarily on the smaller flowers and glandular pubescence of specimens collected from 1897 to 1901 by A. Gattinger. Recent studies have indicated that flower size varies among all members of subsect.Viornae to whichC. gattingeri belongs and should not be considered a significant taxonomic character for species delimitation. Studies using both light and scanning electron microscopy confirm the presence of glandular pubescence on Gattinger’s specimens, but other specimens with glandular pubescence have never since been found.Clematis gattingeri is believed to have been a minor variant ofC. viorna L. and is accordingly placed in synonymy.  相似文献   

12.
Peter Goldblatt 《Brittonia》1975,27(4):373-385
The native bulbous Iridaceae of North America excluding Mexico comprise seven species in four genera. The type species ofAlophia Herb. (1836) is shown to belong toEustylis Engelm. & Gray (1836), hence the latter genus is reduced to synonymy. The well known genusAlophia (sensu auct. non Herb.) (Herbertia Sweet) now takes the nameTrifurcia. As a result of the new interpretation ofAlophia, new combinations are made for the North American and Latin American species ofTrifurcia andAlophia. New chromosome counts are given forNemastylis floridana (2n = 56) andTrifurcia lahue (2n = 56).  相似文献   

13.
James S. Pringle 《Brittonia》1971,23(4):361-393
Two North American species ofClematis, sect.Atragene (L.) DC, are recognized.C. occidentalis (Hörnern.) DC. is divided into three varieties, native respectively to eastern North America, the Rocky Mountains, and the Cascade Mountains of Washington.C. columbiana (Nutt.) Torr. & Gray is divided into two extensively intergrading varieties, one prevailing in the southern Rocky Mountains, the other in the northern foothills and in outlying mountain ranges. After a study of the type specimen ofC. columbiana, it was concluded that this name should be applied to the species hitherto commonly known asC. pseudoalpina (O. Kuntze) A. Nels., rather than to the taxon with which it has usually been associated. The two species are evidently closely related and appear occasionally to have hybridized in nature.  相似文献   

14.
The floral vascular anatomy of 12 species representing each ofAsarum s. str.,Asiasarum, Geotaenium, Heterotropa andHexastylis are compared to clarify intergeneric relationships. The five genera have basically similar structures in floral morphology and vasculature, and consistently have a six-carpelled compound ovary and the associated similar placental vasculature. They show, however, a significant difference in the position and the constituent of the “ventral” carpellary bundles in the placental axis betweenAsiasarum-Heterotropa-Hexastylis andAsarum-Geotaenium. InAsiasarum, Heterotropa andHexastylis the ventral bundles of each carpel are basically free and antilocular as expected in the least specialized compound ovary of angiosperms; in contrast, inAsarum andGeotaenium the ventral carpellary bundles are antiseptal and heterogenous (i.e., formed by the lateral fusion of ventral bundles of adjacent carpels). Shared probable apomorphic floral vasculature, as well as shared single style-column, suggests the closest mutual relationships betweenAsarum andGeotaenium. In terms of floral morphology and anatomy,Asiasarum, Heterotropa andHexastylis retain plesiomorphies. Possible chromosomal evolution in the related genera is also discussed.  相似文献   

15.
A crossing program was carried out between the Kauai endemicB. forbesii and six other Polynesian species, five of which are Hawaiian and one Marquesan. All crosses produced vigorous F1 hybrids, portraying a strong genetic relationship betweenB. forbesii and the other species. The results indicate a close systematic relationship among the Polynesian species ofBidens placed by Sherff in sect.Campylotheca and strengthen the argument that this group dispersed from North America to the Hawaiian Islands, then from Hawaii to the Marquesas Islands.  相似文献   

16.
Restriction fragment analysis of the chloroplast gene psbA was carried out in twelveAbies species native to Asia, Europe and North America using the four restriction enzymes. The pair of Asiatic representatives ofA. koreana andA. veitchii differed profoundly not only from each other but also with respect to the European and Northamerican species. The variation observed within the last mentioned groups of firs was mainly due to the different restriction profiles of the gene inA. alba andA. nordmanniana species of the former region as well as owing to its heterogenous nature in all the four species from North America. The RFLP data presented to far only partially correlate with the taxonomic status and hybridological relationships of the species concerned.  相似文献   

17.
Antagonistic biological interactions with flower consumers and pathogens may influence reproductive success of flowering plants, affecting population dynamics and natural selection for floral traits. However, ecological and evolutionary consequences of the interactions may depend on both spatial and temporal patterns of the interactions. In a forest metapopulation ofPrimula sieboldii E. Morren, an endangered clonal plant species, we measured between-subpopulation patterns of seed sets and interactions with an influential flower consumer, a rove beetle,Eusphalerum bosatsu Watanabe, and a specific smut fungal pathogen,Urocystis tranzschelina (Lavrov) Zundel (Ustilaginales), for three years. Mean female fertility (seed set per flower) for individual subpopulations fluctuated moderately among years but was highly variable within each year among the five subpopulations studied. In two subpopulations, the impact ofEusphalerum beetle, was sufficiently large to result in almost complete failure in seed production over eight years including the three study and five previous preliminary observation years. In the two other subpopulations, seed set failure was caused by infection by the smut fungus. Infected capsules which constitute 10–30% of the capsules produced in the subpopulations were filled with ustilospores instead of seeds. In the subpopulation that escaped flower damage byEusphalerum beetles and smut fungal infection, seed sets of both pin and thrum flowers were much higher than in the other subpopulations. The spatial restriction of individual antagonistic agents to a part of subpopulations suggest that dispersal of the agents, as well as the mode of spatial subdivision of the plant population would be important for determining the overall effects of antagonistic interactions on plant performances at the metapopulation level.  相似文献   

18.
Previous suggestions that prehistoric agriculturalists of the Ozark Bluff Dweller culture utilized a fully domesticated form ofChenopodium have been confirmed. Comparative examination of infructescence and fruit structure indicates that archaeological material is assignable toC. berlandieri ssp.nuttalliae, a product of Mexican agriculture. Large-fruited chenopod remains from other sites in eastern North America, often identified as those of wild species, may also belong to the Mexican domesticated form. A related, wild species of northeastern North America,C. bushianum, shows similarities to the Mexican weed-crop complex that may reflect prehistoric genetic interaction. This is the first documented report of domesticatedChenopodium from prehistoric North America.  相似文献   

19.
Recent generic realignments of the perennial grasses of the tribe Triticeae necessitate some new name combinations for North American species. Three new species combinations and three new subspecies combinations are made to accommodate six long-anthered and usually cross-pollinating species ofAgropyron sensu A. S. Hitchcock in the genusElytrigia sensu N. N. Tzvelev. Three new species combinations are made to accommodate three long-anthered and usually cross-pollinating species ofElymus sensu A. S. Hitchcock in the genusLeymus sensu N. N. Tzvelev. A complete listing is given of the North American species and subspecies ofElytrigia andLeymus as I perceive them.  相似文献   

20.
The ultraviolet reflectance pattern of flowers from 54 species representing 22 families, many native or introduced to Japan, were surveyed. Their differential ultraviolet patterns, i.e. spectral polymorphisms, were recorded by paired photographs of fresh flowers: one taken in full sunlight and the other through a visible spectrum absorbing filter. The different types of polymorphisms observed varied from total absorption by the whole flower to limited absorption by selected floral parts, such as corolla bases (nectar guides) or anthers. Some visible spectrum polymorphisms, e.g. inAnemone andHepatica, were not associated with different ultraviolet patterns. In three species ofIris, a distinct ultraviolet absorbing landing spot and nectar, tunnel guide as well as reflecting anthers are reported. The downward exerted anthers ofSolanum nigrum which shed pollen through bee wing vibration were ultraviolet absorbent. The implications of these ultraviolet patterns for biochemical (flavonoid), taxonomic, pollination and eco-evolutionary research are discussed. Attention is drawn to the seasonal distribution of ultraviolet radiation in the northern hemisphere and its selective role on northern floras.  相似文献   

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