首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
C. C. Berg 《Brittonia》2004,56(3):255-259
Two new species ofPourouma are described, illustrated, and keyed out;P. cordata from Peru and Brazil, andP. montana from Peru.  相似文献   

2.
Summary A comparative study was conducted on the recruitment patterns of two non-pioneer tree species, one dispersed by arboreal mammals and birds (Virola michelii, Myristicaceae) and the other by rodents (Moronobea coccinea, Clusiaceae). These species differ in fruiting phenology, seed size, dispersal distance, germination time and seed nutrient exhaustion. In both species, establishment patterns were consistent with the escape hypothesis and the Janzen-Connell model. Virola seeds need not be buried to survive and germinate, and may produce a seedling carpet beneath the parent. Moronobea seedlings only establish from seeds buried by scatterhoarding rodents in the surrounding understory. One-year survival of Virola seedlings was 47.8% and was greater >10 m than < 10 m from the largest parent tree. In contrast, survival of Moronobea seedlings was 56% 3 years after seed dispersal. Survival of juveniles was greater in gaps than in the understory for Virola but not for Moronobea. Moronobea survival was greater than Virola survival in both microhabitats. Both species establish in the understory, yet both grew faster in gaps. Virola appeared to be more gap-dependent than Moronobea which may persist several years in the understory until a gap occurs. Virola and Moronobea illustrate two intermediate recruitment patterns along an hypothetical continuum of nonpioneer species replacement (Bazzaz and Pickett 1980; Swaine and Whitmore 1988).  相似文献   

3.
A survey of the structure and mineral composition of leaf idioblasts in the Cecropiaceae was conducted. In all six genera of the family, idioblasts usually occur as trichomes or enlarged epidermal cells and nearly always accumulate Si, in marked contrast to the idioblasts of other members of the Urticales, which mostly possess cystoliths containing abundant Ca and Si. The horizontally elongate, mineralized structures ofPoikilospermum, reported formerly as “cystoliths” also contain mainly Si and little Ca. Six genera of Cecropiaceae share a common character in accumulating abundant Si in idioblasts of the leaf epidermis, while lacking cystoliths composed of abundant Ca and Si.  相似文献   

4.
A new species,Bactris nancibaensis, from French Guiana, is described and illustrated.  相似文献   

5.
Eugenia argyrophylla andE. morii from Saül in Central French Guiana are described and illustrated.  相似文献   

6.
Guarea michel-moddei, a new species from central French Guiana is described and illustrated. It differs from the morphologically similarG. cristata of western Amazonia by its unbranched habit; shorter, less dense indumentum of the young parts, leaves, and inflorescence; bullate leaves, shorter inflorescence, shorter pubescence on the corolla; and smaller corolla and staminal tube.  相似文献   

7.
8.
Daniel Sabatier 《Brittonia》2002,54(4):233-235
Vantanea ovicarpa, a new species from French Guiana, is described and illustrated.  相似文献   

9.
Canonical variate analysis of plants raised in a uniform environment was used to study the pattern of geographical variation in leaf shape ofCrepis tectorum (Asteraceae). The diversity in leaf shape was much greater among populations confined to areas with exposed bedrock in the Baltic region than among weed populations scattered throughout Europe and Canada. A Ward's clustering linked outcrop populations from the archipelago of SW. Finland and the islands of Öland (Sweden) and Saaremaa (Estonia) due to the deeply lobed leaves characterizing these populations, while outcrop populations along the coast of E. Sweden were grouped due to their weakly lobed, narrow and dentate leaves. Most of the weed populations were grouped together but there was no tendency for the variation in this group to be related to habitat or geographical location. A mosaic of variation reflected in sharp (random) differentiation among local populations was superimposed on the large-scale ecogeographical pattern.—Crossing data indicated that most of the variation in degree of leaf dissection is governed by one major gene with deeply lobed leaves dominant over weakly lobed leaves. I suggest that the simple pattern of inheritance may have favoured rapid evolutionary changes in leaf shape, particularly in the Baltic area which emerged relatively late from the sea. Genetic correlations may have constrained the pattern of variation at higher taxonomic levels, since some of the trait associations detected in a segregating F2 generation were also found at the among-population level.  相似文献   

10.
Helen Kennedy 《Brittonia》1995,47(2):156-159
Calathea maasiorum from French Guiana and Surinam is described as new. It belongs toCalathea sectionBreviscapus Bentham. The foliage is patterned with a light green band along the midrib above. This new species has previously been confused withC. cyclophora Baker from Amazonian Colombia, Brazil, Venezuela, and Guyana but it is distinguished fromC. cyclophora by the absence of bracteoles, the elliptic to obovate leaf blade, and shorter (1–2 cm long) bracts.  相似文献   

11.
We report the feeding behavior and food preferences of a troop of red howler monkeys (Alouatta seniculus) over two annual cycles in primary tropical rain forest in French Guiana. The monkeys used 195 plant species from 47 families as food. Major food categories were young leaves (54%), mature fruits (21.5%), and flowers (12.6%). Other food categories included old leaves, immature fruits, termitarium soil, bark, and moss. The monkeys were less selective than other howler groups, since 19 plant species contributed 1% to their diet and accounted for only 35.7% of their total diet. The Sapotaceae was the most frequently eaten plant family and represented >10% of the total diet.  相似文献   

12.
Aiouea opaca andBeilschmiedia hexanthera, recently collected in central French Guiana, are described and illustrated.  相似文献   

13.
Spider monkeys (Ateles) frequently use suspensory locomotion and postures, and their postcranial morphology suggests convergence with extant hominoids in canopy and food utilization. Previous studies of positional behavior in Ateles, have produced variable rates in the use of different positional activities. I investigated the positional behavior of black spider monkeys (Ateles paniscus) in a wet rain forest in French Guiana, and assessed differences in the rates of use of positional modes across studies. I also discuss the significance of suspensory activities in forest utilization. In French Guiana, Ateles confined travel and feeding locomotion on small and medium-sized moderately inclined supports in the main canopy. Tail-arm brachiation and clamber were their main traveling modes, while clamber was the dominant feeding locomotor mode. Small horizontal supports were predominant during their feeding. Suspensory postures accounted for more than half of feeding bouts, with tail-hang and tail-hind limb(s) hang being the dominant postures. Feeding occurred largely in tree crown peripheries with the prehensile tail anchored frequently above the monkey. They usually collected food items below or at the same level as the body. There is no difference among the postures they used to acquire and eat young leaves and fruit. My results agree with reports on the positional behavior of different species of spider monkeys at other sites. Despite the use of different methods, the same species exhibited more or less similar profiles in similar forests. Interspecific differences could be associated with morphological differences. Moreover, intraspecific differences could be attributed to forest structure. The findings suggest that the major part of biological information is independent of methods used in the several studies. Suspensory behavior facilitates the exploitation of the forest canopy by shortening traveling pathways between and within trees, by enabling faster travel for the better exploitation of patchy food sources and by providing access to food in the flexible terminal twigs.  相似文献   

14.
Eric Gouda 《Brittonia》1994,46(2):134-136
The new combination,Disteganthus lateralis, is coined based onAechmea lateralis. An illustration for this species is provided.  相似文献   

15.
以采集于贵州、云南、广西、湖南等地的火棘、密花火棘、全缘火棘、细圆齿火棘和窄叶火棘共5种火棘属植物26 401个成熟叶样为材料,利用WinFOLIA软件测量叶的多项形态指标并与叶面积进行11种模拟方程回归分析。结果表明:五种火棘属植物的叶面积(LA)与叶长×叶宽(LW)相关性最高,幂函数方程、三次方程、二次方程和线性方程能较好拟合其关系,且均以幂函数方程的解释程度最高(R2均大于0.970),5个物种的幂函数方程分别为LA=0.743(LW)0.936、LA=0.748(LW)0.936、LA=0.742(LW)0.955、LA=0.732(LW)0.952、LA=0.766(LW)0.954。这说明基于叶长×叶宽的叶面积幂函数方程能很好地来模拟五种火棘属植物的叶面积。  相似文献   

16.
Analysis of morphological and phenological data for determining the genetic variation within sevenLolium species led to the recognition of two groups within this genus. One group, containing the two inbreeding speciesL. temulentum andL. persicum, was clearly distinct from all other species. Strong morphological and phenological intergradation was found between both species. The cross-breeding species,L. perenne, L. rigidum, andL. multiflorum, formed another group. Little differentiation was found between these species, though they were distinct. Two inbreeding species,L. loliaceum andL. remotum, were clearly distinct from each other and the two groups.L. loliaceum had an isolated position and was most related toL. rigidum. L. remotum had an intermediate position between the cross-breeding and inbreeding species, and was almost equally distant from all three cross-breeding species.Genetic variation inLolium spp. I.  相似文献   

17.
A biometric study of theSarcocapnos crassifolia complex from eastern Andalusia (Spain), Algeria, and Morocco was carried out. Twentytwo populations were used in a principal components analysis based on 14 variables. The results support the recognition of two species,S. crassifolia andS. pulcherrima, spec. nova. The taxon described byBoissier asS. speciosa (S. crassifolia subsp.Speciosa) is maintained inS. crassifolia.  相似文献   

18.
Morphological field studies of 27 populations of theA. meridionalis complex were conducted in Ecuador. It is possible to distinguish four different form series by the position of the stamens in relation to the style. This trait was congruent with the overall morphometric variation, shown by the results of a canonical discriminant analysis (CDA). The taxonomy of the species complex is discussed based upon the results of the CDA. The degree of outcrossing varied in different form series, from a comparatively high degree of selfing to predominantly outcrossing, as indicated by the variation within relative to among populations. This is probably due to the varying potentials for self-deposition owing to differences in the degree of herkogamy.  相似文献   

19.
Seed oil composition (sterol esters and sterols) and seed protein profiles ofCondalia microphylla were investigated. The chemical differences observed may be attributed to genotypic changes and could support the existence of infraspecific taxa.  相似文献   

20.
Morphometric characters on 118 herbarium specimens ofLomelosia crenata subsp.crenata (regarded as including subsp.pseudisetensis) were statistically evaluated to detect discontinuities in the variation pattern. Three morphotypes were detected: specimens with short stems and long calyx bristles, specimens with short stems and short bristles, and specimens with long stems and short bristles. The first morphotypic group is separated from the others, which are partly overlapping. These groups broadly correspond toL. crenata subsp.crenata, toScabiosa crenata var.glabriuscula, and toL. crenata subsp.pseudisetensis, respectively.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号