THE PLANT GROUPS 131 



those of ferns a matter of chance or one of blood 

 relationship ? 



c. Roots. Are the roots of cycads distinctive ? If so, in 

 what respects ? 



3. Asexual reproduction. Study living or preserved material 



or museum specimens. 



a. Strobili. Determine the position of strobili on the 

 main axis, the distribution of male and female 

 strobili on the same or on different plants, and the 

 general nature of the strobili. 



(1) Are the strobili terminal or lateral in origin ? Are 



the plants monoecious or dioecious as regards the 

 distribution of strobili? 



(2) Are the parts of the strobilus arranged on the same 



plan as those of the main plant body ? To what 

 parts of the plant body do the main parts of the 

 strobilus correspond ? Are there sporophylls and 

 a central axis as in the lycopods and Selaginellal 

 Are the sporophylls cyclic or spiral? 



4. Sporophylls and sporangia. 



a. Microsporophylls, sporangia, and spores. 



(1) Sporophylls. Note the form and relation of the 



sporophylls. Compare (by means of specimens 

 or figures) the sporophylls of different kinds of 

 Cycadales. Are any of them leaflike ? To what 

 do these sporophylls correspond in ferns ? in 

 Selaginella and lycopods ? 



(2) Microsporangia. Are the microsporangia abaxial or 



adaxial on the sporophyll? Has their position 

 any relation to spore-shedding? Is there any 

 definite arrangement into sori ? 



(3) Spores. Searcli for sporangia shedding spores. Is 



there a definite line of dehiscence? Study spores 



