64 COMPARATIVE EMBRYOLOGY OF THE RUBIACEAE 
their structure, persistence, food content, and the behavior of the 
surrounding tissues. 
The genus Crucianella offers an exception to the general con- 
dition in the Galieae. Although antipodals are developed no evi- 
dence has been obtained that they take on any special cytological 
characters. Indeed their tenure of life is so short that the three 
antipodal cells have not been seen at the same time. Their func- 
tion is probably, therefore, at best but passive, and is carried out by 
the mere giving up of their substance in death to the embryo-sac. 
In Diodia teres, also, the number of antipodal cells is three, but 
present a difference in that the long one is relatively much shorter, 
a feature which is undoubtedly correlated with the smaller amount 
of archesporial tissue. They may, however, not be considered as 
physiologically inactive since they secrete a large amount of starch, 
and persist for a long time. 
In Diodia Virginiana the number of antipodals is greater, the 
number varying, so far as observed, between four and ten. These 
are arranged in a long series, physiologically equivalent to the 
single long antipodal in the GaZeae. The subsidiary megaspore 
mother-cells, as above pointed out, persist and form a continua- 
tion of the series. The antipodal cells retain their normal char- 
acter for a considerable period covering the earlier period of endo- 
sperm development. : 
In Richardsonia and //oustonia the antipodal cells are equal in 
all regards, and appear to have fess permanent value. They 
acquire the cytological characters of glandular cells such as are 
found in certain nectarial tissues and stigmas, and are probably 
active in some kind of secretion. "Their relative small importance 
as judged by their size is connected with the behavior of the 
embryo-sac cell and the much suppressed archesporium. 
That, in the words of Westermaier (4. c., Part 1), we have to do, 
in the antipodals, with “an anatomical-physiological apparatus, 
and not with a useless rudimentary structure which may be under- 
stood only from the viewpoint of comparative morphology,” * is 
evident from the facts as here summarized : 
= is of great interest in this connection to recall the remark of “Hofmeister made 
Mim fty years ago : “ Die am Chalaza-Ende entstandenen, durch ihre betráchtliche 
rösse oft sehr ausgezeichneten Zellen scheinen keine andere Bestimmung zu haben, 
als die der Verarbeitung des Nahrungsstoffes für den werdenden Embryo." Die Ent- 
stehung des Embryo der Phanerogamen, p. 59. 1849. 
