and Fertilization in Oenothera. 
3i* 
produced in correlation with accumulation of starch grains in the nucellar 
tissue. But the result of microchemical observations denies any nutritive 
substance existing there, and, on the contrary, it suggests something 
like ultimate products. 
The writer therefore examined several species of other genera of 
the Onagraceae with a view to finding a clue to solve the question. 
Unfortunately, the result of the investigation did not fully answer the 
expectation, but a close relation existing between the hypostase and starch 
grains in nucellus was found, which is shown in the following table : 
Material. 
Starch grains in 
Hypostase , i.e. the tissue 
containing chromatic , 
Cuticularization 
of the walls of 
the nucellus. 
substance in the 
the inner 
Oenothera nutans, pycnocarpa, 
many 
chalazal region. 
+ *■ 
integument. 
+ 
biennis var. canescens , and 
0do rata 
Gaura parvijlora 
many 
+ 
+ 
G. Lindheimeri 
many 
-t 
+ 
Circaea quadrisulcata 
many 
+ 
+ 
Ludwigia prostrata 
not so many 
— 
+ 
Jussieua repens 
few 
— 
+ 
Epilobium angustifolium 
very few 
— 
+ 
Godetia sp. 
none 
— 
+ 
Fuchsia macrostemma 
none 
— 
+ 
From this table it can be seen clearly that the deposition of numerous 
starch grains generally occurs when the hypostase is present, and that 
the chromatic substance interferes with nutritive communication between 
the nucellus and conducting passage. 
Lastly, the question may be discussed from the phylogenetic point 
of view. As to the affinity among the genera of the Onagraceae, Par me n- 
tier’s taxonomical and anatomical investigation ( 54 ) led to the conclusion 
that the most primitive type was found in the group to which Ludwigia 
and Jussieua belong, and that from this group Oenothera was originated 
and gave rise to other genera. Accepting his conclusion, and reflecting on 
the result of the present investigation, we can assume that the primitive 
types scarcely possess hypostase, while in certain derived genera, such 
as Oenothera and Gaura , the tissue in question is present. It is curious, 
however, that Godetia , a genus closely related to Oenothera , is entirely 
destitute of this tissue. In Epilobium , which is a direct derivative of 
Oenothera , this tissue disappears secondarily, and the same is also the case 
with Fuchsia , a genus allied both to Oenothera and Ludwigia . On the 
other hand, it still exists in an isolated genus, Circaea . 
It may therefore be concluded that the presence or absence of 
hypostase and starch grains has no relation with the tetranucleate condition 
of the embryo sac which is a diagnostic character of the Onagraceae. 
