July, 1902.] 



KNOWLEDGE, 



161 



evidcnoe which strongly supports the theory sug£;ested by 

 Kapteyn ami nthers, that the ap])aroiit motion is due to 

 changes ofillutiiiQation in a statiouary nebula. — A. F. 



Botanical. —The " Flora of Tibet or High Asia" is the 

 title of a long paper by Mr. AV. B. Heinsley in the last 

 part of the Journal of ike Liniwiii Socii'tij. The enumera- 

 tion of Phanerogams and Ferns shows the flora to consist 

 of 283 species, belonging to 119 genera and -tl natural 

 orders. It is estimated that alx)ut 12 per cent, of the 

 sjiecies are endemic, but that further research will probably 

 lead to a reduction of this number. The Compositic are 

 most numerous, there being 53 species, and after them 

 come, in the sequence here given, the Grarainea?, Crucifene, 

 Ranunculacea;, and Lcguminosoe, as the most largely 

 represented v)rders. The flora for the most part consists 

 of very dwarf annual or liei-baceous plants, often not 

 exceeding two or three inches in height above the ground, 

 but possessing extraordinarily long tap-roots. Six species 

 are recorded from altitudes of 18,000 feet or more, one, 

 Saiissiirea triducli/la, ascending to 19,000 feet. 



In the i)art of Hooker s Icones Planianim just issued 

 an imusual number of interesting novelties are described 

 and figured, including no less than seven new genera. 

 Carolinella (Primulaceiv) is a Chinese plant allied to 

 Primula, but having a distinct habit and a circumscissile 

 fruit as in Anatjallig. Thomassetia is an anomalous genus 

 of Terustnemiaceiie from the Seychelles, and Hartia, 

 belonging to the same order, is from China. The latter is 

 placed near Stuartia. Paradoinbeya CSterculiaceae) is 

 rejiresented by two species, one from Burma, the other 

 from Yunnan. The flowers of P. hutmanica are snow- 

 white in a fresh state, but turn yellow in drying. 

 Diuranthera (Liliaceaj) resembles Anlhericum, and difiers 

 chiefly in having tailed anthers. This, with the two new^ 

 geneni of TJmbeUifera? (Cnjj)tofieniopsis and Carlegia), are 

 natives of China. — S. A. S. 



Zoological. — Specimens of the okapi recently received 

 at Brussels serve to sliow that the adults of both sexes 

 were furnished with horns, apjiarently very similar in 

 general character to those of giraffes, being covered with 

 skin. The Brussels specimens comprise the skull of a 

 male and the skin of a female. A small photograph of 

 the skin was exhibited by Dr. Forsyth Major at a recent 

 meeting of the Zoological Society. At the same meeting 

 Mr. G. A. Boulenger showed a strip of skin from the leg 

 of an okapi which had been received in Belgium from 

 Mangbettiiland in December, 1899, a year previous to the 

 arrival- in this country of the two strips upon the evidence 

 of which E(^uH8 johiigk ui was named. 



Another exhibit on the occasion referred to above was a 

 mounted specimen of a wild shee|) killed by Mr. J. Talbot 

 Clifton on the mountains bordering the Yana Valley, 

 Liberia, apparently the Ovis borealis of Severtzoff, and 

 believed to be the first of its kind brought to England. 

 It was shown to be nearly allied to the wild sheep of 

 Kamchatka, which is itself closely related to the bighorns 

 of North America. 



In the June number of the Zoologist, Mr. Gunning, of 

 the Pretoria Museum, records the birth of a hybrid 

 between a male ass and a female Burchell's zebra. In 

 general character the midc appears to be much more like 

 its sire than its dam, having no stripes. It is hoped that 

 it may be immune to tsetse-poison and horse-sickness. 



The Eoyal Society has issued the first of a series of 

 reports to the Evolution Committee, describing experiments 

 undertaken by Mr. W. Batesou and Miss E. R. Saunders. 



These ex]»eriment's, which have been made both with 

 plants and with poultry, were undertaken with a view of 

 determiniug whether variations exhibited by animals and 

 plants are distinct phenomena, according as to whether 

 they are continuous or discontinuous. Their result is to 

 fully confirm the truth of " Mendel's Law." of which the 

 essential part is that the germ-cells produced by cross- 

 bred organisms may in certain respects be like one of the 

 pure parental types, and consequently incapable of re- 

 producing the characters of the other. Hence there may 

 be almost complete discontinuity betweeu tliese genus m 

 respect of one of each pair of opposite characters. This 

 doctrine is likely to have a far-reaching i-ffect on our 

 conception of the origin of species. The experiments are 

 being continued. 



STUDIES TN THE BRITISH FLORA. 



By R. Lloyd Praeger, b.a. 

 IV.— THE PROTEAN OFFSPRING OF FERNS. 

 In my last article the normal forms of our British Ferns 

 were under brief consideration. In discussing the curious 

 phenomenon of apospory, it may have been noticed that, 

 in every instance, this was detected, not in the type form of 

 anv species, but in some abnormal variety. The abundance 

 of these varieties in our native Ferns, and their marvellous 

 range of variation, are very remarkable features, well 

 worthy of consideration. In no other group of plants 

 throughout the whole vegetable kingdom do we find such 

 an amazing range of abnormal forms. They ai-e often 

 treated as mere florist's monstrosities, and no more worthy 

 of recognition by the botanist than the rainbow-tinted 

 galaxy of Chrysanthemums or Pansies ; Init two facts 

 concerning them place them at once on a different footing. 

 First, as many and as remarkable Fern varieties have been 

 found in a state of nature as have been produced by the 

 combined efforts of all the horticulturists ; and secondly, 

 a large number of them reproduce themselves absolutely 

 true generation after generation, and are even capable, as 

 we shall see, of carrying (by crossing with other forms) 

 their peculiar characters into other varieties. Fui-thermore, 

 the features which distinguish these abnormal forms 

 follow certain definite lines even in species of widely 

 separated genera, and are capable of classification. A 

 remarkable point about these Fern varieties is that they 

 are essentially a British group of plants, and their study 

 is a British hobby. While some foreign Ferns yield wel]- 

 known varieties — such as the crested forms of several 

 species of Pteris and Maidenhair — still these are as nothing 

 compared with the wonderful number and range in 

 character of those which have been found wild in our 

 islands, notably in the south-west of England. Another 

 curious point is that the species which are so variable 

 with us appear to lose this character even in neighbouring 

 countries. France and Germany have yielded one or'two, 

 but only one or two varieties, where English hedgerows 

 have yielded literally hundreds. These varieties, sports, 

 monstrosities, or whatever we choose to designate them, 

 have occasionally a wide distribution, in which case they 

 frequently obtain recognition from systematic botanists— 

 as Ceterach officiiiariim, var. crenatum, Asplenium Adiantum 

 nigrum, var. acutuin, and Polypodium vjdgare, var. 

 serratuiii, all of which are merely the first stage of the 

 frond-dissection which, as' we shall see, is carried im- 

 mensely further in a number of our common Ferns. In 

 other cases large or small colonies of a variety are formed, 

 as, for instance, Blechiium Spicant, var. /ri/iervium, which 

 occurs in thousands on the Mourue Mountains in County 



