92 



" Nectar— a fluid always sapid, usually sweet, often odorous, whirh 

 IS elaborated in any part of a plant, remaining where formed or 

 making its way to some other part; its raison d'etre bein^ the 

 necessity for the removal of some useless or injurious substance or 

 as some provision to attract nectar-loving animals to the plant 'for 

 some definite purpose." This is rather long for a definition, and it 

 might be objected that it includes resinous exudations. After group- 

 ing the various positions of the nectaries under the general heads of 

 floral or extra-floral, Mr. Trealease discusses specially those on the 

 several divisions of these parts. 



On the cotton plant the most copious source of nectar is the base 

 of the bracts which surround the flower, and to it, are attracted 

 many ants, ^^^asps and bees, and during the night previous to the 

 flovvers unfolding thousands of the moths whose larvae are most 

 destructive to the flowers and fruit. " So it appears 'that the secretion 



^tf t.= f '" '' ^"'-'^^u' ?' ^^'^'^ ^"^"^^^^ ^f the plant, and then 



?nr nnl tW •. T' k'"'' 'r^^'^ •^^^'■^ '' P^^^'^' relief from the mis- 

 lortune that it has brought on itself." - 



The whole essay will be found entertaining and Instructive 

 Appended IS a very valuable index to all books or articles treat^^n J 

 of nectar and the fertilization of flowers in general. ^^eatin^ 



§ 70. Irritability in Robioia—The Comptes rendus of the 

 French Academy (Tome XC. No. 21) contains a not byMr T 



cacia, 1^-1 he author tried some experiments last year to ascer- 

 tain whether he could produce in this tree phenomena of sens - 

 k the'^e ^[tirolfnf ''h' "f Dutrochet's tern?) like those obs^vd 

 five oVlock t tlSTf • ^T. experiment was made at half-past 



brfghtlv He ound th^r" ""^ w^'"'- ''^'\^ ^^"^ ^'^^ ^^'^ ^^'^^ shining 

 Dngntiy. He found that on subjecting the terminal leaflet to 10 to 



20 quite strong raps with his finger, the lateral leaflets soon beean to 



approach each other, and that at the end of five mnutes the whole 



eaf was m the same state of " sleep " as at midnight' The llteS 



re'ttrm^l°"'le"ffleTlfst"- 1 °^'^^' 'k^^^""^"^ ^'^ ^'^ - '-t 

 , ,)^?: leanet, just as they are observed to do in the sendfivf- 



plant. The author found that it afterwards required two or hee 

 hours strong sunshine to cause the leaflefQ tn i^ ^^ V 



their horizontal position. SuLequently he l Ld fhe'^^^^^^ 

 heat on the terminal leaflet, and found that he ronWh ^^.f^^^"^ 

 crisp without afi-ecting the lateral leaLts-^a result h1. 7'' '' '"• ^ 

 to that obtained in alike experiment with the sen th" pt'nt'^'?;:: 



"thelTter^l^t^'^Fr^om^tf "°^^^ "°^^ ^'^^'^ in th?J:rmer'^^ H 



be hilTain'ednddUral'rviL^^e^^rrup^^^^^^ o"^:^ ""^^'^ ^'^" 

 forth by him in 1876, that: " The reason whvth. oP^ion put 



sensitive plant have been regard.rl !f= ^ u "^."^^ments of the 



present time, they have be4 looked aT.^T''".?-' ^' '^^^^' "P ^^ "^^ 



tional, whereas th'ey are only tKighest decree of'l '^""T 



phenomenon, the traces of wh>Vh w5 ^ f ^ / development of a 



. vegetable kingdom » ^^^ ^"^ "^^^ ^°"^^^ throughout the entire 



*!• 



