13.] The Embryo-sac in Acer rubrum. 377 
brum is similar to that which takes place in few families of 
beth monocotyledons and dicotyledons. 1 ; 
__ It may be of interest to note that the pollen spores formed 
lithe anthers of female flowers (fig. 12), though never becom- 
‘functional, develop normally. They are, as far as obser- 
-Mition goes, almost precisely like those of the functional male 
flowers (fig. 13) with the two nuclei present which stain sim- 
"tltly to those of the functional spores. They are, however, 
he nuclei having a less definite membrane and 
the protoplasm Consisting of a coarser reticulum, while the 
ads are, however, as yet enclosed by the wall 
Shortly after the flower opens these an- 
imbedded in paraffin, and sectioned on a Minot mi- 
ome, after which the sections were counterstained on the 
* Seventy per cent. alcoholic solution of Bismarck 
i eed in Canada balsam. 
Niversity, Bloomin ton. 
Er LaNation 
: are : vule; 
Shon “aad Pate XXXIV.—Fig. 1, ope aber oe of young © 
' le 
Tes of male 
; ‘Tessa, : . 
: GER; Angiospermen und Gymnospermen, Jena, 1879. 
f 
