218 



INTRODUCTION TO CRYPTOGAMIC BOTANY. 



juncture with the new frond, to which it is attached, till it has 

 attained its normal form or dimensions. The fruit consists of 

 incrassated cells springing vertically from the frond, the endo- 

 chrome in some cases being finally quadripartite. Thuret, 



Fig. 56. 



a. Quadripartite endochromes of Lessonia nigrescetis. 



b. Ditto, in Echlonia flahelliformis, J. Ag. 



Both from drawings by Dr. Hooker.* 



Magnified. 



however, figures zoospores as produced from the endochrome, 

 but whether in essentially distinct cells or not is, perhaps, 

 doubtful. Harvey speaks both of spores and antheridia, but 

 on what grounds I do not know.-f It should be observed, 

 moreover, that Thuret has proved the zoospores to be repro- 

 ductive in Chorda lomentaria, Chorda filum, and two 

 Laminarice. There is therefore no reason for supposing that 

 real spermatozoids exist in this division, though it affords 

 another instance of a binary mode of propagation. 



202. Of the two main divisions of this order, viz., those with 

 definite leaves, and those which have a frond which is a mere 



* I have also, from the same quarter, drawings of quadripartite endo- 

 chromes in ^cHojiict hiruncinata 3Ji& Alaria Pylaii. They are to be 

 found also in some of the LaininaricB of our own coasts. Dr. Montague 

 was the first observer of the quadripartite spores in Echlonia runcinata. 



t Dr. Harvey says that in Chorda JUum there are mixed with the 

 vertical spores numerous narrow elliptical transversely striated cells 

 which may be antheridia. Thuret, as stated in the text, has recorded 

 the germination of the minute zoospores in this species. 



