THE TAXONOMIC SIGNIFICANCE OF THE HEAD-SCRATCHING METHODS OF BIRDS.

Birds scratch their heads in one only of two ways, either directly or indirectly, and one method is used by all members of the same family though not necessarily by all families in the same order. When related families have different head-scratching methods, then the behaviour can help in disentangling difficult relationships. Examples are given. In the case of the passerines, only the Timaliidae (babblers) scratch directly. The implications are briefly discussed; for example, on this evidence Picathartes is not a babbler. The Psittaciformes are a potentially rewarding group for future work.     

TWO NEW PARROTS (PSITTACIFORMES) FROM THE LOWER EOCENE FUR FORMATION OF DENMARK

Abstract:  Two new fossil psittaciform birds from the Lower Eocene 'Mo Clay' (Fur Formation) of Denmark ( c . 54 Ma) are described. An unnamed specimen is assigned to the extinct avian family of stem-group parrots, Pseudasturidae (genus and species incertae sedis ), while a second ( Mopsitta tanta gen. et sp. nov.) is the largest fossil parrot yet known. Both specimens are the first fossil records of these birds from Denmark. Although the phylogenetic position of Mopsitta is unclear (it is classified as family incertae sedis ), this form is phylogenetically closer to Recent Pstittacidae than to other known Palaeogene psittaciforms and may, therefore, represent the oldest known crown-group parrot.     

HEAD-SCRATCHING AMONG NORTH AMERICAN WOOD-WARBLERS (PARULIDAE)

A survey of 40 species of 14 genera of North American wood-warblers (Parulidae) reveals that the head-scratching method employed is surprisingly stable within species. The experiments by Nice & Schantz (1959a, b) induced some normally overwing head-scratchers to scratch the head under the wing. It is suggested that this was because their leg rings became caught in secondaries, making normal overwing head-scratching impossible. A few exceptional head-scratching patterns under different conditions invariably involved normally overwing head-scratchers employing the underwing method, and a few species head-scratch under the wing as nestlings but change to overwing before fledging. In all, 31 species appear to be normally overwing head-scratchers, seven are underwing head-scratchers, one species uses both methods and one remains uncertain. There is no evidence for lateral preference in either head-scratching method, and head-scratching is only loosely linked sequentially to preening. The functional significance of head-scratching may be related to blockage of the eustachian tube, or to cleaning and oiling the feathers. Avian head-scratching is more difficult to homologize with mammalian head-scratching than others have considered it to be, but all evidence suggests that within birds underwing head-scratching is phylogenetically primitive. In wood-warblers, the head-scratching method does not correlate with taxonomy. However, ground-dwelling wood-warblers tend to scratch the head under the wing and arboreal wood-warblers over the wing. This correlation provides the first strong clue to the functional significance of the difference between methods in passerine birds.     

PHYCOLOGY IN THE FIELD AND IN THE LABORATORY1

Field and laboratory phycologists are still following different paths. This is regrettable because their labors supplement one another, and only by co-operation can progress be achieved.     

江西省河流水生植被

江西省地处长江中下游交接处的南岸,境内有大小河流2400多条,总长约18400km。江西河流水生植被的组成植物隶属27科,36属,共61种,且可划分为14个主要群落类型,其中以苦草、黑藻、竹叶眼子菜、(艽木)和菹草、微齿眼子菜、金鱼藻等沉水植物群落分布较广,面积较大;而适应流水和水深变化能力较差的挺水、浮叶及漂浮植物仅零星分布在河流边岸、河湾水潭边缘或河滩低洼处等。     

暖温带山地森林的小气候研究

本文探讨了暖温带山地落叶阔叶混交林和油松林不同梯度的气温、湿度、土壤温度的日变化特征,不同季节的分析结果表明：１．落叶阔叶林夜间始终存在气温随高度增加而增加（第１梯度＞第２梯度＞第３梯度＞第４梯度）的辐射逆温现象。油松林夜间林内气温观测值始终低于林冠以上值。２．在生长季的不同时期,人工油松林的林内气温（林地以上２ｍ和４ｍ）的日间波动程度和振幅都高于林冠以上（林冠顶以上０．５ｍ和２．５ｍ）。而在生长季中期,充分发育的落叶阔叶林林冠能够明显地缓减林内气温波动和振幅。３．两类林分各梯度的气温一般均在正午后２～３小时内达到高峰,而早晚较低,具有明显的日变化特征。４．落叶阔叶林林冠以上２．５ｍ处的水汽压及相对湿度始终低于林地以上４ｍ（林下灌木层以上２．５ｍ）处的同期值,具有比油松林更强的增湿效应。     

黄河源头地区植物的区系特征

黄河源头地区位于青藏高原东北部,属于昆仑山东部范围之内,约占东经９６°００′,－９９°２０′,北纬３３°５０′－３５°４０′,海拔大都在４３００－４８００ｍ之间。气候具有高原大陆性气候的特点。本区共有种子植物４１科、１４２属、４６２种,分别占青藏高原植物亚区唐古特地区总科数的４５．１％,总属数的２９．４％,总种数的２８．１％,是唐古特地区中植物种类最贫乏的地区。植物的区系特点如下：１．种类贫乏;２