CamBRIDGE, Massacuusetts, Aucust 10, 1938 
HARVARD UNIVERSITY 
A REMARKABLE FOSSIL SELAGINELLA 
WITH PRESERVED FEMALE 
GAMETOPHYTES 
BY 
WitiiaM C. DarRAH 
Or ALL PLANTS known to the botanist, Selaginella is 
one of the most familiar. It is regarded as the classical 
example of a heterosporous plant. Selaginella has been 
recognized in the fossil record as far back in geological 
time as the lowest Cretaceous, but several earlier species, 
based upon fructifications, are similar enough to the liv- 
ing genus to be referred to Selaginellites. This form- 
genus is known from rocks of Carboniferous, Permian, 
and Mesozoic age. 
Recently there was found in a newly acquired collec- 
tion of fossil plants, received by the Botanical Museum of 
Harvard University from the environs of Mazon Creek, 
Illinois, a small strobilus bearing four large spores in each 
sporangium. The striking resemblance of this strobilus 
to strobili found in living species of Selaginella was es- 
pecially interesting, because the perfect state of fossiliza- 
tion suggested the probability that cellular detail might 
be preserved. Following a study of the specimen by a 
combination of the maceration and peel methods, it was 
discovered that the fossil contained numerous early fe- 
male gametophytes which exhibited remarkably well- 
preserved nuclei and nucleoli. So numerous were these 
[ 118 ] 
