148^4\ Spore Formation in Torreya californica. 
Fig. 22c. Embryo-sac mother-cell from an ovule collected May 21st, 1902. 
(X 600). 
Fig. 23. Longitudinal section of part of the nucellus of an ovule collected 
May 17th, 1904, shewing embryo-sac mother-cell and the surround¬ 
ing cells drawn in outline only. ( x 300). 
Fig. 24a. Terminal fertile shoot collected June 9th, 1902. A pair of ovules 
is seen in the axil of one of the lower leaves (Nat. size), cf., the 
terminal bud in Fig. 21a. which shews the condition of this shoot as 
it was a month earlier. 
Fig. 24b. Embryo-sac mother-cell with nucleus in synapsis from the longi¬ 
tudinal section of an ovule collected June 9th, 1902 ( x 600). 
Fig. 25. Embryo-sac mother-cell with nucleus in synapsis from a longitudinal 
section of an ovule collected May, 17th, 1904. ( x 600). Note the 
brush of fibrils in the protoplasm at the basal end. 
Fig. 26. Embryo-sac mother-cell with nuclear thread in the beaded condition. 
(x 600). From a longitudinal section af an ovule collected June 
1st, 1904. 
Fig. 27a. Ovule with its bracts removed, (x about 4). Collected June 24th, 
1902. The arillus surrounds the base of the conical integument 
which is truncated by the micropylar opening. 
Fig. 27b Embryo-sac mother-cell shewing part of the spindle of the reduction 
division ; from a longitudinal section of an ovule collected on June 
24th, 1902. (x 600). 
Fig. 28. Embryo-sac mother-cell shewing part of the spindle of the reduction 
division from an ovule collected June 24th, 1902. The pre¬ 
paration has been treated with aqueous iodine. This has caused 
swelling of the wall and chromosomes and has darkened the 
masses of starch grains which occupy the ends of the mother-cell 
at this stage, (x 600). 
Fig. 29. Embryo-sac mother-cell after the completion of the reduction 
division ; from the longitudinal section of an ovule collected June 1st, 
1904. (x 600). 
Fig. 30. Embryo-sac mother-cell from the longitudinal section of an ovule 
collected June 7th, 1904. The lower cell has already divided into 
two, while a spindle is visible in the upper cell. ( x 600). 
Fig. 31. Embryo-sac mother-cell from a longitudinal section of an ovule 
collected June 1st, 1904. The division into four spores has now 
taken place. ( x 600). 
Fig. 32. Embryo-sac (megaspore) capped by three degenerating and flattened 
sister-cells from a longitudinal section of an ovule collected June 
22nd, 1904. (x 600). 
[Note.— All the microscopic figures have been drawn from single 
microtome sections, except Fig. 31, which was drawn from two 
successive sections. 
The embryo-sac mother-cells are all drawn in the position which 
they would occupy if the axis of the ovule were vertical, and the 
micropyle was directed towards the top of the page.] 
