186 BOTANICAL GAZETTE [September 



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remarkably distinct in cross-section (fig. 54), for the walls do not 

 change on that side, but remain thin, composed of cellulose. 



The seta, measuring about 2 mm. in length, would be described 

 as having a club-shaped foot if it can be called a foot. Even when 

 the seta consists of a few tiers of cells, the glandular appearance at 

 the base is striking. Tissues of the calyptra and seta disorganize so 

 that at the base of the seta there are always some glandular cells 

 and others very much crushed. During its growth the bulbous base 

 of the gametophyte and sporogonium has turned from a horizontal 

 to a vertical position. 



The capsules dehisce progressively along the thallus from early 



spring (March) through May. Goebel (10) has well described 



the dehiscence and shedding of spores in Aneura palmata. The seta 



elongates rapidly (Nemec 20) from 2 to 30 and more mm., in the 



field often twisting on its own axis. Individually its rectangular 



cells lengthen from 60 p to 500 and 600 /^. This pushes the capsule 



far beyond gametophyte and calyptra. Along the well marked 



lines between the valves, about one-third of the way from the tip 



at the greatest width of the capsule, a splitting begins. The crack 



lengthens until with a jerk the valves are bent back. Some spores 



are freed now, but the majority are shed by the next movement 



of the valve, when its fourth of the elaterophore springs upward 



45 or more. Spores and elaters fall together, the tetrad often 



complete. 



Germination of spores 



Plants with capsules about to shed were brought from the field 

 March 23, April 15, May 17, and May 20, and put on wet cotton 

 under bell- jars or in large Petri dishes. Spores were sown as soon 

 as the capsules burst. On sterilized cotton the spores (averaging 

 60-68 or 70 /*) are soon lost. A better medium and more easily 

 examined under the microscope is made by putting a layer of heavy 

 white filter paper over wet cotton in a Petri dish. Porous clay 

 plates are also good. Drop cultures in 0.5 and 1 per cent cane 

 sugar, 2.5 and 3 per cent glucose, 0.5 and 1 per cent lactic acid, 

 0.3 and 0.6 per cent Knop solution, vegetable lipase, distilled 

 water, all died after reaching the two-celled stage. The excessive 

 amount of moisture was one cause of this, for cultures made at the 



