INTRODUCTION TO CRYPTOGAM IC BOTANY. 



225 



which change to a verdigris green when exposed to the 

 atmosphere. The spores are sometimes the metamorphosed 

 joints of scattered threads, but frequently the threads are 

 compacted into distinct receptacles. The species are perhaps 

 less known than some others as regards their fruit, from their 

 being deep-sea plants, and therefore only obtainable in a good 

 state by dredging. There has been a good deal of discussion 

 as to their affinity, but if the larger species be considered, 

 there is but little doubt that they are rightly placed here. 



Fig. 58. 



a. Spore threads of Arthrocladia villosa, magnified. 



b. Pedunculate receptacle of Sporochnus pedunculatus, ditto. 



c. Spores on the threads from the receptacle.* Both from specimens 

 dredged at Weymouth. 



Many of the species produce tufts of delicate filaments, which 

 have, however, nothing to do with the fruit. The same species 

 varies singularly in breadth, the extreme forms being so 



* It will be observed that the threads'are sometimes terminated with 

 a swollen sub-pileiform cell much after the fashion of Carpomitra 

 Cabrera. 

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