TYPES OF CRYPTOGAMS; PTERIDOPHYTES 251 
325. Fertile Stems. — Describe the fruiting stem with reference to 
general aspect, size, color, number, and length of internodes, position 
of spore-bearing portion, color of spores in mass. Note the shield- 
shaped bodies (transformed leaves or sporophylls) composing the 
cone-like « flower,” and see whether any joints 
can be detected where they are attached. 
Examine the inner surface of the shields for 
sporangia and spores. Examine the spo- 
rangia under a low power of the microscope. 
Examine some spores under a higher power. 
Note the two bands, elaters, on each spore, 
crossing each other and attached only at the 
point of crossing, forming four loose append- 
ages. Watch these while some one moistens 
them by gently breathing upon them as they 
lie uncovered on the slide under the micro- 
scope and note the effect. Also note the 
effect of drying. How does this affect the 
spores? Use of the bands? 
326. Germination of Spores. — The spores 
germinate while fresh and form prothallia 
corresponding to those of ferns, but gener- 
ally dicecious. The prothallium which bears 
the antheridia remains comparatively small, 
and the antheridia are somewhat sunken. 
The others grow much larger and branch 
profusely. The terminal portion becomes 
erect and ruffled. Near this part the arche- 
gonia are formed, quite similar to those of 
ferns. The embryo plant developing from 
the germ-cell has its first leaves in a whorl. 
This at length grows into a spore-plant like 
that shown in Fig. 174. 
Fic. 175. Part of a 
Lobe of the Mature 
About twenty-five species of Equisetum are Female Prothal. 
known. Several may be looked for in any lium of Equisetum. 
locality and may well be compared with the (x about 50.) 
Beat Q ] recarc O +75 
one described above, in rega d ai form, mode a, mouth of a fertilized 
of branching, and mode of fruiting. archegonium. 
