Gnetalean and Bennettitean Seeds. 
141 
the condition of certain Bennettitean seeds in which, as Dr. 
Scott remarks in the “ Studies in Fossil Botany,” the micropyle is 
usually closed. Indeed the sections through the apex of these 
seeds of Gnetum show in many respects resemblances to the 
drawings of Bennettites Morierei published by Professor Lignier 1 
in 1894. 
The ovules of Gnetum gnenion in question were about 7 m.m. 
in length ; the embryo-sac was nearly filled with a thin-walled 
tissue, but no trace of embryos could be detected. 
Transverse sections through the extreme apex show a withered 
micropyle, the wall of which consists of three or four layers of 
flattened cells, bearing internally a well-marked columnar epi¬ 
dermis. This is surrounded by the edge of the perianth, which 
also shows signs of withering. 
Fig. 2. Transverse section near the tip of the micropyle. x 150. 
Fig. 2 represents the micropyle just below the withered 
portion. Here the wall is six or eight cells thick, the thickening 
being apparently partly due to tangential divisions of the cells 
below the outer epidermis. Lower down similar divisions take 
place in the cells beneath the internal epidermis with the result 
that the micropyle is reduced to a mere slit. Lower down still 
the outgrowth of some of these cells into the small cavity completes 
the blocking of the passage, as is clearly shown in Fig. 4, and in 
cross-section we appear to get a solid cylinder of tissue (Fig. 3). 
Similar growth and proliferation of the cells takes place in the 
outer layers of micropylar wall. Here a kind of flange is produced, 
which fits over the upper edge of the outer integument. In the longi¬ 
tudinal section figured, contraction due to fixation in alcohol accounts 
1 Lignier, O. (’94). Structure ct Affinites du Bennettites Morierei, 
Mem. Soc. Linn. Normandie, Vol. xviii., Ser. 2. 2. 
