CAREX GRACEII SP. N., CYPEROCARPUS ELIASII SP. N., CYPEROCARPUS TERRESTRIS SP. N., AND CYPEROCARPUS PULCHERRIMA SP. N. (CYPERACEAE) FROM THE MIOCENE OF NEBRASKA

Silicified achenes and some perigynia of four new sedges are described from the late middle or late Miocene Ash Hollow (Clarendonian or Hemphillian) and early middle Miocene Sheep Creek (Late Hemingfordian) Formations of Nebraska. Carex graceii, sp. n., Cyperocarpus terrestris, sp. n., and Cyperocarpus pulcherrima, sp. n., were collected from strata in Garden and Antelope Counties and Cyperocarpus eliasii, sp. n., was collected from strata in Sioux County. Certain of the newly discovered taxa exhibit considerable anatomical detail of the pericarp wall of the achene. In two taxa, Carex graceii and Cyperocarpus pulcherrima, the achene pericarp exhibits four topographic regions: a cuticle, an outer layer of pentagonally to hexagonally shaped epidermal cells containing silica bodies, a middle layer of sclerenchyma cells, and an inner layer of sclerenchyma cells whose long axes are perpendicular to the long axes of the cells of the middle layer. Similar pericarp anatomy was found in Cyperocarpus terrestris except that the inner layer was not observed. In the fourth taxon, Cyperocarpus eliasii, only an outer epidermal layer of elongate cells with small protuberances is preserved. The ultrastructure of the pericarp of the fossil taxa is similar to that of living forms. Associated flora and fauna indicate widespread savanna environments with significant riparian elements. This is the first systematic treatment of sedges from the Miocene of North America.     

窄口螺侧殖吸虫的发育史及早熟现象

1.本文描述从福州闽江泥滩采集的图氏窄口螺体中发现一新种侧殖吸虫,定名为窄口螺侧殖吸虫(Asymphylodora stenothyrae sp.nov.)并与其他相近虫种作详细比较。2.窄口螺侧殖吸虫的生活史各期发育经详细观察,本文简单介绍其各发育期形态特征。3.本文对窄口螺侧殖吸虫早熟现象及其他吸虫类的提早发育现象进行讨论,并将复殖吸虫亚纲曾经发现有提早发育现象的虫种及其中间宿主列表比较。我们的结论:早熟现象在吸虫类中是相当普遍的一种现象。       

Nicotiana Deformis N. SP. und die Enzymtheorie der Erblichkeit

Ohne Zusammenfassung     

NITZSCHIA ALICAE SP. NOV. AND N. PURIFORMIS SP. NOV., NEW DIATOMS FROM EUROPEAN RIVERS AND COMPARISON WITH THE TYPE MATERIAL OF N. SUBLINEARIS AND N. PURA1

Nitzschia sublinearis Hustedt and N. pura Hustedt are common oligosaprobic freshwater diatom species that frequently occur in diatom inventories, thus being important in water quality studies. Both are considered as species with overlapping diagnostic criteria in several floras, which is typical of the whole genus Nitzschia. The type material of Hustedt of N. sublinearis and N. pura was examined using LM and EM in order to document the range of variation within the type populations and to compare it with populations occurring in different European rivers. Detailed observations allowed recognition of two new freshwater diatom species: N. alicae sp. nov., occurring in mesotrophic up to eutrophic conditions, and N. puriformis sp. nov., mostly occurring in oligotrophic habitats, both in rivers and streams at middle and high altitudes. The most reliable taxonomic features that separate both new species from the most similar taxa are the density of fibulae and striae, valve shape, and valve width as well as the shape of areolae. Morphological examination of different populations indicates that N. puriformis is relatively common in European rivers and has been overlooked to date and confounded with N. pura by several researchers. By contrast, N. alicae has, to date, been collected only in Slovakia and Northern Italy, but with a high frequency of occurrence and sometimes in high abundance at sites.