PTERIDOPHYTES— LYCOPODIALES 295 



In those species which have the green aerial portion, the spores 

 germinate at once, soon prockice archegonia and antheridia, and the 

 sporehng becomes estabhshed by the end of the season. L. inundatum 

 is our only species with this kind of prothallium. In this country, as 

 far as we know, prothallia have not been found growing wild, and no 

 one has germinated the spores. The spores germinate in 10 days to 6 

 months, develop up to the 8- or 10-cell stage, and die, doubtless from 

 the lack of the proper fungus. No one but Bruchmann has had any 

 notable success in germinating the species with subterranean tuberous 

 prothallia. 



In some species, the spores do not germinate for several years, but 

 when the prothallia are once developed they continue to bear arche- 

 gonia and antheridia for several years. The spores of L. Selago germi- 

 nate in 3-5 years after shedding; those of L. clavatum and L. annotinum 

 in 6-7 years. In L. clavatum and L. annotinum archegonia and an- 

 theridia develop in 12-15 years after the spores are shed. 



Botanists in Lijcopodium localities should look for prothallia. Since 

 the subterranean forms are perennial and as large as a grain of wheat, 

 some reaching a length of 1.5 cm., it would seem as if they should be 

 found wherever Lycopodhnn grows. 



In the third edition of this book, pubhshed in 1915, the statement 

 was made that no one had yet discovered prothallia of Lycopodium in 

 the United States. Two years later, a teacher in the high school at 

 Marquette, Michigan, Dr. E. A. Spessard, announced the discovery 

 of the prothallia of four species and gave such clear directions for find- 

 ing prothallia that already two papers have appeared, announcing the 

 discovery of prothallia. One of these papers, by Dr. Alma Stokey and 

 Dr. Anna Starr, describes seven stations for prothallia in Massachu- 

 setts; and the other, by 0. Degener, adds four more stations in 

 Massachusetts and mentions the finding of prothallia near the crater 

 of Kilauea, Hawaii. Both papers appeared in the Botanical Gazette of 

 March, 1924. With such a start, others began to find prothallia. Look 

 for tiny sporelings, just above ground. They may still be attached to 

 the prothallia. Where you find a sporeling, take a layer of soil 2 or 3 

 inches deep and examine it carefully for younger stages. Prothallia are 

 more likely to be found at the edges of a patch than where Lycopodium 

 is very abundant. 



The archegonia and antheridia are borne on cushions on the upper 

 part of the prothallium (Fig. 92). 



