February 1, 1892.] 



KNOWLEDGE, 



31 



^^ AN ILLUSTRATED "^^ 



MAGAZINE OF SCIENCE 



SIMPLY WORDED— EXACTLY DESCRIBED 



LONDON: FEBRUARY 1, 1892. 



CONTENTS. 



PAGE 



British Mosses. By the Et. Hon. Lord JrsTicE Fry. 



F.R.S., F.S.A.. F.L.S. 21 



The Chemical Element Carbon. Br Tafghan Corxish. 



B.Sc, F.C.S 25 



What is an Ant.3 By E. A. Btjtlee 27 



The Canons of Colorado. By the Eer. H. X. HriCHixsoy, 



B.A., F.G.S. Illustrated by Photograph 29 



Letters :— T. S. Barrett ; W. H. S. JIoxck 33 



Notices of Books 35 



The Relative Brightness of the Planets. By J. E. CtOre, 



F.R.A.S. " 35 



Periodical Comets due In 1892. By ^. T. Ltxn, B.A., 



F.R.A.S 37 



The Face of the Sky for February. By Herbert Sadler, 



F.R.A.S 38 



Chess Column. By C. D. Locock, B.A.Oxon 38 



BRITISH MOSSES. 



By tbe Et. Hon. Lord .Justice Fry, F.R.S., F.S.A., F.L.S. 

 [Continued from page 7.) 



WE have seen that Nature has been practising a 

 piece of severe economy iu doing without the 

 spore and the whole machinery adapted for 

 the production of spores and substituting a 

 gemma for a spore. We shall now see her 

 going a step further in the same course of economy and 

 doing without the gemma. She will produce protonema 

 from the existing Moss plant without the intervention of 

 spore or gemma. 



Fig. 15 represents a,\eQ.ioi Orthotrkhum Lijel I i, a. Moss 



Fid. 15. — Leaf of Orthotrichum LyelH, after Schimper. 



found both in the old and the new world, on the trunks 

 of trees : from this leaf, and especially from its midrib, are 

 seen growths of protonema, and these gradually change 

 into true roots, and on these roots buds are formed, which 

 buds develop into true JIoss plants. At x will be seen 

 such a protonema divided into cells by transverse walls — 

 fm-ther on the walls are oblique to the line of growth, and 

 the growth then assumes the form of a root — and at >/ is 

 seen a bud destined to produce a Moss plant. 



Other species of Moss produce protonema from other 

 parts of their structure ; sometimes from the small roots 

 or rhizoids, sometimes from the base or the margin of the 



leaf, sometimes from the stem, and sometimes from the 



calj^Jtra or veil. These modes of reproduction are referred 



to in the third column in table B, under the heading 



"Moss." 

 But Nature has not yet 



tired of economy, she will 



try a yet shorter circuit of 



Ufe ; she will reject the pro- 

 tonema, as well as the spore, 



and produce on the existing 



Moss plant itself a bud which 



shall produce a new Moss 



plant. Sometimes leafy buds 



are formed on the true rhi- 

 zoids, sometimes on the root- 

 like hairs which hang sus- 

 pended in the air and are 



known as aerial rhizoids ; 



sometimes bulbs are foimd 



on the stem, and from these 



buds and bulbs fresh Moss 



plants arise. A yet more 



direct mode of propagation 



may exist, viz., the direct 



production of a Moss plant 



from a Moss plant ; whether, 



in this case, a bud is first 



formed or not I do not know, 



though I should suspect the 



affirmative. This curious 



mode of reproduction is shown 



in Fig. 16, which depicts a 



plant of Sphagnum cuspida- 



tuiii, on the ends of the loose 



leaves of which {a, a) are 



seen numerous young plants 



directly arising and alike in 



all things but size to the 



parent plant. 



The last-mentioned modes 



of reproduction are epitomi- 

 zed in the last two columns 



of table B. 



There is one reflection 



which must almost have 



forced itself on every reader 



in considering this sketch of 



the development of Mosses, 



and of the economies of 



Nature in the process. The 



one object of her solicitude 



is the Moss plant — whatever 



else be left out, this is al- 

 ways present : Nature may 



strike off the spore, she may 



do without the gemma, she 



may avoid the protonema, but do whatever she may she 



f fffeij-" 



1 



Fig. 16. — Sphagnum cuspi- 

 dafum. aa,youn£plant9atendB 

 of branches. After Schimper. 



