March, igo6.] 



KNOWLEDGE & SCIENTIFIC NEWS. 



38 



the discovery of Themis, the tenth satellite of Saturn. This is 

 sometimes brighter or fainter than Phcebe, and the latter 

 appears to be variable. The Blue Hill Meteorological Station 

 has been maintained, as before, at the expense of Mr. A. L. 

 Kotch. During 17 kite records of the upper air, the average 

 altitude was 6940 feet, and the maximum height attained was 

 11,180 feet. With hiiUoiis-soiuit's a height of 48,700 feet was 

 reached, the temperature recorded being — 111° F. 



^^^^^^ 



BOTANICAL. 



By G. Massee. 



Floral Colours and Pigments. 



TllF, colours ,,l lloucrs, Irom a biolo.^Mcal Nlandpoint, have 

 received iiiLich attention during recent years, but, as a rule, 

 the colour, as we ordinarily see and interpret it, has formed 

 the main or only basis for comparison. In the Journal of 

 the Koijal Hdrficiiltiiral Society Mr. Bidgood has treated the 

 subject from a different and more fundamental standpoint. 

 Plants do not inherit colour from their parents, but the 

 pigments which possess colour or colours as their most 

 characteristic properties. Further, if a pigment is inherited 

 it does not necessarily follow that the colour of that pig- 

 ment should be of the same hue as that of the parent. A 

 plant m.ay inherit from one parent an uncoloured substance 

 which, with a pigment from the other parent, as in the case 

 of a hybrid, may modify the pigment so that the colour is 

 altered. Finally, a hybrid may inherit an uncoloured sub- 

 stance from each parent, which may re-act on each other 

 and produce a pigmented or coloured substance. It is 

 indicated that knowledge of this kind should prove very 

 useful to those interested in hybridisation and the produc- 

 tion of new colour varieties of plants, as it would prevent 

 much time being wasted, and a striving after the practically 

 impossible. Students of Mendel would also benefit by de- 

 voting mure attention to the inheritance of pigment, rather 

 than to the inheritance of colour. 



A flower is seen by the light given off from its surface, 

 much of it after having penetrated to a greater or less ex- 

 tent, and after having been more or less decomposed by the 

 pigments present in the cells. If the pigmented particles 

 consist of green corpuscles or chlorophyll grains, underlying 

 a red dissolved pigment, the chlorophyll would absorb 

 nearly all the light that passed through the red solution, 

 and little or none w'ould reach the surface again. The result 

 would be a dark neutral brown or black. The outer side of 

 the llowcr of Crocus avreus has green stripes near the base. 

 This colour is due to the combined effect of blue anthocyanin 

 in the epidermal cells on that side, and to a yellow xanthic 

 pigment on the other. The black blotches on the leaves of 

 Arum n^aculntum are the result of crimson anthocyanin 

 overlying green chlorophyll. 



.Subjective colours due to the interference of light in thin 

 films, frequently seen in animals, does not appe.-ir to exist 

 in plarils. 



Relations of the Algal Floras of the N. 



Atlantic, the Pola.r Sea, and 



the N. Pacific. 



It has long liri ri l<iu>\\ n thai a great m.iny pl.'ints in the 

 northern hemisphere have a circumi)olar distribution. Plants 

 of the tertiary period occupying districts around the Pole 

 were driven .southwards to the Continents of our time during 

 the glacial period, and on its cessation slowly wandered b.ack 

 to their original home. .At the .same time "these plants left 

 some of their representatives in their southern tcmpor.iry 

 home. By these means we account for those species which 

 every .\rctic district has in common with the mountains 

 south of it, but not with other districts. This knowledge, 

 however, only applies to llowering plants, and as far as 

 m.Trine alg.-e are concerned hut little has been attempted in 

 this direction previous to the work bv Sitnmons in the 

 Hdfaniichcii Centrallihift. In early tertiary tim<-s the Pol.ir 

 .Sea possessed .-i distinct flora limited from the .\tl;mtic flora 

 by ,-1 land-bridge now .•ibsrnl. .\ similar h.arrier also 



separated the Pacific Ocean from the Polar Sea. On the 

 disappearance of these barriers the Polar algae invaded the 

 .\tlantic and Pacific, and the glacial period drove more algie 

 south, leaving the Polar .Sea almost devoid of plant life. 

 .\ftcr the glacial period some algae returned to their old 

 home, and this condition of things is still in progress so far 

 as conditions allow. .Many of the tertiary Polar species have, 

 however, not been able to return, owing to adverse condi- 

 tions. As a result there are now some .\llantic and Pacific 

 .■dg» respectively that had their origin in the Polar Sea, but 

 are now .absent from there. On the other hand, some old 

 .\tlantic algae that became adapted to cold during the glacial 

 period, migrated to the Polar Sea along with the returning 

 original .Arctic alg£e. This theory accounts for the hetero- 

 geneous assemblage of types of algae in the Polar Sea at the 

 present day, and also for the presence of .\rctic typos in 

 wh;U are considered indigenous s[>ecies in the .Atlantic and 

 I'.icific Oceans respectively. 



On the Occ\irrence of Starch and 

 Glxicose in Timber. 



A point of mucli economic i[iiport,incc ha> been announced 

 by Professor Kirk in the TifuisadioHS of the Xew Zealand 

 Institute. Examination of a considerable series of worm- 

 eaten wood of various kinds showed that in every instance 

 such wood contained starch or an abundance of glucose, and 

 it is for the purpose of feeding on these substances that the 

 larvw of beetles attack timber. In the case of white pine 

 {roilocnrpus ilm ri/difnl, s) it is recommended that the trees 

 be cut when the sii.ri.l starch has been converted into soluble 

 glucose, and tlv liiiil" 1 iljowed to remain exposed for some 

 time to till' .Rtion of w.itir tu dissi,l\|. out the glucose. 



Mycorhiza. on R^oots of Trees. 



The presence of mycorhiza or growths of fungus mycelium 

 on the roots of many plants has long been known, and 

 various investigators, more especially Frank, consider that 

 such growths are of great service, if not even indispensable 

 to the nutrition and health of the plant thus infected. 

 Transeau in discussing the flora of the bogs of the Huron 

 River Valley, in the Botanical Gazette, expresses the opinion, 

 founded on field observations, that in Larix mycorhiza are 

 only developed when the ground in which the plant is grow- 

 ing lacks aeration, and more especially when the roots are 

 surrounded by water, .\cidity of the liiedium in which the 

 plant is growing does not favour the development of 

 mycorhiza. Whether the fungus is of actual advantage to a 

 plant, even when growing in a poorly aerated soil yet re- 

 mains to he determined. These conclusions corroborate those 

 of others who have recently studied the subject, and point 

 to th.' conclusion that the amount of importance attached to 

 m\corliiz;i by l'"r.uik is exaggi'rated. 



CHEMICAL. 



By C. AiNswoKTH Mitchell, B.A. ((Jxon.), F.I.C. 



Poisonous Plants used for Catching Fish. 



Till number of tropical plants which find a practical use in 

 the catching of fish is very large, no fewer than J44 ditTerent 

 kinds having been described by M. Greshoff. They belong to 

 different families, but chiefly to the leguminacea;. euphorbace;c 

 and sapindace:e. The active clieniical constituents to which 

 they owe their toxic power are equally varied, and include 

 alkaloids, glucosides, volatile oils, resinous bodies, pnissic 

 acid, etc. The compounds of most frequent occurrence have 

 been found by Dr. Kobert to belong to the saponines, the best 

 known example of which is found in the soap-wort, in the root 

 of the clove pink, and in the horse chestnut. When extracted 

 from these by means of boiling alcohol saponine is deposited 

 as a powder when the solution cools. It is readily soluble in 

 water, and the solution forms a lather like soap, whence the 

 name of the compound. Dry, powdered saponine produces 

 sneezing when inhaled. Another class of substances has been 

 isolated by Dr. GreshofT and other Dutch chemists from 

 leguminous plants belonging to the natural order Dans, and 

 notably from the root of /). .Uif^tica, which occurs in Java and 

 the neighbouring islands, and has been especially studied by 



