HARD WICKE'S SCIENCE- G OS SIP. 



141 



different plants, the female flowers differ very little, 

 if at' all, as regards the situation or form of the floral 

 envelopes. But when the plant is monoecious, the 

 glumes of the two sexes are widely different. These 

 differences are most marked in certain genera of 

 Chloridccs, normally dioecious, and accidentally 

 monoecious. The grass named BucJiloe dactyloides is 

 a curious example in point. Besides this is now 

 placed Opiza stolonifcra, of which Presle had only seen 

 the female plant. Although the flowers of these plants 

 differ vei-y widely, their male plants resemble each 

 other so much that they have been grouped in the same 

 genus. Castiostega humilis is the male form oiBuchVde, 

 and Castiostega anoinala the male form of Opiza. 



Insects and Flowers. — In a lecture recently 

 delivered by Sir John Lubbock on ' ' Certain Relations 

 between Insects and Plants," Sir John shows the 

 probable use to plants of hairs, &c., on stems and 

 flower-stalks. Although flowers tempt flying insects, 

 it is not to the advantage of flowers that ants, which 

 are decidedly nectar-loving insects, shall rob the floral 

 nectaries of their contents. Ants could not produce 

 crossing by crawling over flowers ; and Sir John 

 Lubbock suggests that hairs covering flower-stalks 

 are usually bent with the points downwards, and act 

 as a chevaux defrisc, hindering ants and other useless 

 insects from crawling up. Thorns and prickles are 

 equally protective against snails and slugs. When 

 the flower-stalks are smooth, the flower-head is often 

 covered with teeth or hairs, as in the cornflower 

 (Centaurea cyamts). When Polygonittm amphibium 

 grows on land, the stems are covered with hairs, 

 which secrete sticky matter to deter crawling insects 

 from reaching the honey-laden flowers. But when 

 the same plant grows in water the stem is smooth, 

 inasmuch as there is no fear of creeping insects in the 

 water. 



Yew-poisoning. — We often hear of cases of 

 cattle dying from partaking of the leaves of the Yew. 

 M. Mavine has found a poisonous alkaloid in the 

 leaves and seeds of the common Yew ( Taxus baccata), 

 which is named Taxiiic. It is nitrogenous, and 

 evolves ammonia when heated with freshly-ignited 

 soda-lime. Taxine is present in larger quantities in 

 the leaves of the Yew than in the seeds. 



The Alkaloids of the Greater Celandine 

 (Chelidonium viajus). From chemical experiments 

 which have been made on this plant by E. Masing 

 the following results have been arrived at : There is a 

 diminution in the total amount of alkaloids before 

 flowering, and a marked increase a few days after- 

 wards. The young plant gathered in autumn shows 

 a regular increase of alkaloids. The weather is an 

 important matter in the contents of alkaloids. In 

 rainy weather the consumption is greater than the 

 production, whilst in sunny weather consumption and 

 production are nearly in equilibrium. These changes 

 are more noticeable in the root than in the leaf. A 



good soil influences the formation of alkaloids ; and 

 plants grown in gardens were found to have double 

 the amount of alkaloids found in wild plants. 



GEOLOGY. 



How to clean Fossil Polyzoa, etc. — All col- 

 lectors of carboniferous polyzoa have frequent occasion 

 to notice that in the case of large handsome specimens 

 of FeiicsteUiS and allied forms the polypiferous face is 

 unfortunately seldom that which is exposed. This 

 circumstance of course considerably lessens the value 

 of the fossils, and those among the readers of 

 Science-Gossip who are inclined to follow Mi-. 

 Vine's excellent example, and become collectors of 

 the palaeozoic "sea-mats" and "bottle-brushes" 

 will be glad to know how the evil in question may be 

 remedied. Mr. John Young, F.G.S., of the Hun- 

 terian Museum, Glasgow University, has very suc- 

 cessfully solved the difiiculty by applying the slabs 

 bearing the polyzoa on to plates of asphalt heated to 

 a proper degree of softness. The original shale is 

 then removed, and the fenestellcs are found, polypi- 

 ferous face uppermost, adhering to the hardened 

 asphalt in a perfectly natural manner. This may 

 appear to some a rather risky process of dealing with 

 tender fossils, but an examination of the very beauti- 

 ful results which Mr. Young has obtained by this 

 means, and which form one of the many attractions 

 of the fine carboniferous series under his care, will 

 set such fears at rest. I may add that I have tried 

 the method myself with invariable success. — G.A. L. 



The Metropolitan Well Borings. — Some 

 misunderstanding has taken place in the public news- 

 papers as to the views of geologists respecting the 

 Metropolitan under-ground water supplies. At 

 Messrs. Meux's brewery, Tottenham Court Road, the 

 base of the gault has been penetrated, and a depth of 

 one thousand and fifty-nine feet from the surface 

 reached. From minute examinations of the lowest 

 cores, there are reasons for believing the lo'ocr green- 

 sand has been reached. If this should prove to be 

 the case, the water-supply of London will be practi- 

 cally inexhaustible. Twenty-seven years ago Prof. 

 Prestwich published a work on the " Water-bearing 

 Strata in and around London," wherein he stated 

 (although no boring about London had then been 

 carried more than three hundred feet into the chalk), 

 that the chalk would be penetrated at a depth of 650 

 feet. Subsequent borings proved this prophecy to be 

 correct in several instances. Later on, Mr. Godwin- 

 Austen showed the probability of an ancient ridge of 

 primary rocks stretching under the upper cretaceous 

 system, along the line of the Thames valley ; and the 

 deep boring at Kentish Town, and another at Har- 

 wich, also proved Mr. Godwin-Austen to be correct. 

 Prof. Judd thinks that although this old ridge of 

 primary rocks must limit the area of the available 



