VAILLANTIA HISPIDA 9 
end of the ovule lies in a lower horizontal plane than does the base 
of the funicle. The micropyle and embryo-sac lie in a curved line, 
and the funicle remains short. The ovule is therefore not of the 
strictly anatropous type, but is campylotropous, approaching the 
anatropous condition. (Pl. 3. Fig. 1.) During the process of in- 
version the longitudinal axis comes, of course, to lie in the hori- 
zontal plane, and about this time a number of the hypodermal 
cells under the apex of the nucellus elongate in a direction parallel 
with the longitudinal axis of the nucellus. (Pl. 1. Fig. 2.) These 
cells, about 12 in number, constitute the archesporial tissue, and 
are recognizable at first only by their size. Their subsequent 
changes will be described below. The large number of sporog- 
enous cells here found to constitute the archesporium recalls the 
condition in Rubus caesius, Geum strictum and Sanguisorba officinalis, 
in which, according to A. Fischer* ( 80) numerous sporogenous cells 
arise. A similarly large number of these cells has also been found 
in Casuarina,t in Loranthus} and in Ranunculus. § This character, 
which appears in several widely separated families is probably 
therefore not to be regarded as a persistent primitive character in 
the Rubiaceae at any rate, but one having a physiological meaning, 
as will be shown later. The sporogenous cells now elongate, and 
their elongation is accompanied'by periclinal division in the epider- 
mis and subadjacent cells of the tissue about the apical part of the 
nucellus. (Pl. 1. Fig. 3.) Only in the columnar epidermal cells 
immediately beneath which lie the sporogenous cells there occurs 
no division, periclinal or otherwise. These, therefore, remain as a 
cap of cells, about which arises the integument at first as a low 
ridge, but gradually growing over the nucellar cap and forward so 
as to form a canal which I shall call the micropylar canal, the 
outer end of which forms, in the definitive ovule, the micropyle. 
The manner in which the integument has its origin recalls 
vividly the figures by Warming || (78) of the nucellus of Thesium, 
one of the Santalaceae. In the body of the paper the author asks 
— 
the question “ Are these ovules in which the nucellus is not cov- 
* Jenaisch. Zeit. f. Nat. 14: 122 
۱ 18803. 
t179. 1875. 
