1895. ] Briefer Articles. 31 
EXPLANATION OF PLATE IV.—Fig. 1. Lobe of leaf of Geranium Carolinianum 
L., attacked by Synchytrium. Slightly magnified.—Fig. 2. Section throug 
confluent pustules on vein of leaf. Section does not pass exactly through cen- 
ter of pustules; X 60.—Fig. 3. Section through center of pustules; granular 
mass almost fills the cavity, and resting-spore lies imbedded in lower part; 
X 150,—Fig. 4. A large resting-spore; X 315.—Fig. 5. Section through cavity 
containing pevaead resting-spores; X 315.—Fig. 6. Sorus, with portion of red- 
dish brown covering adhering to one side; X 315.—Fig. 7. Sporangium of 
same; X 315 
Formule for life histories.—I have found certain formule very use- 
ful in presenting general life histories to my classes. I do not know 
whether others are using themor not. If not, it might be well to sug- 
gest them, for they are very helpful in fixing the broad facts, 
G = gametophyte; o = gamete; O = spore (sexual or asexual); 
S = sporophyte. 
0 
Lsospory = il oo Directing aici, 
ee 
Gas 
Heterospory — a re 
Ceieaig ost Paced 
= bi weap Ai apogeny, with 
G o————-G 
Apogamy = Piers 
Creat ie Bed 
err rence 
sea ms per agence, with 
Zan, ospory- 
Aporpory:= cose 
and so on ad infinitum. 
This is useful not only in presentation but in quizzing. For in- 
Stance, ask a student to indicate in this way the life history of an an- 
8iosperm, a fern, a mildew, anything. It seems to make it very real 
to him.—Joun M. Courter, Lake Forest, Ills. 
