tO CIBCUMNUTATION OF SEEDLINGS. CHAI>. 1 



on the following day with nearly the same result; and there 

 can be no doubt about the cireumnutation of the hypocotyl. 



Primula Sinensis : conjoint eircumnutation of hypocotyl and cotyledon, 

 traced on vertical glass, from 8.40 A.M. to 10.45 P.M. Movements of 

 bead magnified about 26 times. 



Cyclamen Persicum (Primulaceao). This plant is generally sup- 

 posed to produce only a single cotyledon, but Dr. H. Gressner * 

 has shown that a second one is developed after a long interval 

 of time. The hypocotyl is converted into a globular conn, even 

 before the first cotyledon has broken through the ground with its 

 blade closely enfolded and with its petiole in the form of an arch, 

 like the arched hjpocotyl or epicotyl of any ordinary dicotyle- 

 donous plant. A glass filament was affixed to a cotyledon, -55 

 of an inch in height, the petiole of which had straightened itself 

 and stood nearly vertical, but with the blade not as yet fully 

 expanded. Its movements were traced during 24 2 h. on a 

 horizontal glass, magnified 50 

 times ; and in this interval it 



"V described two irregular small 



\ r' \ circles; it therefore circumnu- 



\ f ^tl \^ r~-/^h\ tates, though on an extremely 



" ' \T^^ small scale. 



*qf*. sarpcdon: circumnutation .^'^ "*!**" < AB ? 6 ' 



of hypocotyl, illuminated from piadero). - This plant, when 



above, traced on horizontal glass, mature, resembles a cactus. 



IT 28 4 fh A - M -i n p e . 2 230-r 4 o 8 - 4 c 5 The flattened hypocotyl is 



Movement of bead magnified 21 flesh y' enlarged in the upper 



times part, and bears two rudimen- 

 tary cotyledons. It breaks 



through the ground in an arched form, with the rudimentary 



cotyledons closed or in contact. A filament was affixed almost 



* 'Bot. Zeitung,' 1874, p. 837. 



