1909] WIELAND—WILLIAMSONIAS OF MIXTECA ALTA 439 
ae fg To. BS Boat Siacrine and actual sei a the See of ee 
pothetical homosporous fronds. 
"8, heterosporous pteridophyte 
4,h 
dices Romosporous ear 7 pteridophy tes pines: 
a ; an prey of B (Permian; Cycas); BY”, staminate derivative of B 
etalous angiosperms; D, fu rther 
all the essential organs and parts 
carpel, stamen, petal, a and sepal 
C, reduced form of B 
and a "progenitor of famop 
reduction stage of C, with, seenaath of giving r 
a pet tfect flow ee pee stamino-petal ‘D"; 
greed derived from BF 
a, true ca 
pitlalers carpellary leaf; b, reduced carpellary leaf; 
I, true a frond (Williropen ESO - sa leading to gamo- 
reduc rue stamino-petal; 4, 
c, pedicellate ovule or seed 
rms;. 2,°tr 
Gr 3’, a7 ’, second method a sepa petals iets 
Cyca We Shih AD xEs.—B’ + B” (I-IV) =Co ectatta)et; Coniferales, Ginkgoales, 
Ma, et A+C Vi Cra raat many proangiosperms; A’'+C (VD= 
Cc agg laceae, Liriodendropsis, etc.; C (VIl)=many types of naked cg ictal 
spe (VIII) =gamopetalous a gee ae forms; eae =many a 
t™ms; A +a=proangiospe 
