8 BOTANICAL GAZETTE [JULY 
were tube nucleus, stalk cell, and body cell. It is hardly to be expected 
that two prothallial cells will be present in one species and wholly 
absent in another. 
The number of prothallial cells varies in gymnosperms. Those 
in which two have been reported are Ginkgo, Strasburger (’92); 
Larix europaea, Strasburger (’84); Picea vulgaris, Belajeff (93); 
Pinus Laricio, Coulter and Chamberlain (’o01); Podocar pus coriacea, 
Coker (02); Ceratozamia longijolia, Juranyi (’82), sometimes two, 
but more often one. Those in which one has been reported are 
Ceratozamia, Juranyi (’82); Zamia, Webber (’97); Cycas, Ikeno 
(98); Ephedra campylopoda, Strasburger (’72). No prothallial cells 
have been observed in Biota, Cupressus, and Juniperus, Strasburger 
('92); Laxus baccata, Juniperus, Belajeft (93); Thuja occidentalis, 
Land (’o2); Taxodium distichum, Coker (’03); Cupressus (4 spp-); 
Taxus baccata and 4 vars., Juniperus (2 spp.), C. hamaecy paris (5 spp-), 
Callitris, Cryptomeria japonica, and Thuja orientalis, Coker (’04); 
Ephedra helvetica, Jaccard (’94). 
It is quite probable that in many gymnosperms two prothallial 
cells will be found eventually, and probably one at least will be found — 
in some of those forms where up to the present none have been 
demonstrated. 
THE OVULATE STROBILUS. 
The ovulate strobilus was first collected in December. It differs 
in external appearance from the staminate strobilus in that it is longer 
and more slender. 
The ovulate flower is not differentiated as early as is the stami- 
nate. On March 1, 1903, traces of the outer and inner integuments 
could be seen; a few days later the integuments presented the appear- 
ance shown in fig. 23. Much has been said concerning these integu- 
ments or perianths, as they are variously called. Transverse sections 
at different levels (figs. 24, 25) show that the outer integument results 
from a fusion of four leaves, and the inner integument from a fusion 
of two leaves. The outer integument becomes several cells thick, 
and in later stages quite hard. The inner integument is never more 
than two cells thick. A short time before the pollen is shed, the 
inner integument rapidly elongates and thrusts itself out through the 
apex of the strobilus. The exposed end is wide. open, and is also 
