Pteridophytes Lycopodiales 223 



sions in the spore mother cell stain intensely, so that care must be 

 taken not to overstain. 



The gametophyte. In most species the gametophyte, or prothal- 

 lium, is subterranean, tuberous, and has no chlorophyll; in other 

 species the prothallium is partly subterranean and partly aerial, the 

 aerial portion being green and bearing the archegonia and antheridia. 

 So far as the author is aware, no one has ever found prothallia of 

 Lycopodium in the United States, although the prothallia of several 

 of our species, like L. inundatum, L. clavatum, and L. annotinum, are 

 well known from European material. Nearly all the work on Euro- 

 pean species has been done by Bruchmann, of Gotha, Germany. No 

 one else has ever found enough material for any extended research. 

 He advises collectors to look, not in dense patches of the plant, but 

 at the edges of the patch. Look for small plants, and if plants only 

 1 cm. or so in height are found, then dig carefully for prothallia. 

 With the exception of L. inundatum, forms which are partly aerial 

 have been found only in the tropics. 



It would seem natural to get the prothallia by germinating the 

 spores, but here again no one has had any notable success, except 

 Bruchmann. In some species, the spores do not germinate for several 

 years, but when the prothallia are once developed they continue to 

 bear archegonia and antheridia for several years. The spores of 

 L. selago germinate in 3 to 5 years after shedding; those of L. clavatum 

 and L. annotinum in 6 to 7 years. In L. clavatum and L. annotinum 

 archegonia and antheridia develop in 12 to 15 years after the spores 

 are shed. L. inundatum germinates more promptly in 10 da} r s to 

 6 months but no one has succeeded in keeping a culture up to the 

 archegonium stage. 



Botanists in Lycopodium localities should look for prothallia. 

 Since the prothallia of L. clavatum reach a length of 1 . 5 cm., it would 

 seem as if they should be found. 



From material kindly furnished by Dr. Bruchmann it can be said 

 that the prothallia, once secured, are easy to cut and stain. 



Selaginella. Material of Selaginella, in all phases of the life 

 history, is easy to secure, but not so easy to handle after it is obtained. 

 As many as 340 species, mostly tropical, have been described, only 



