596 
STRUCTURE AND LIFE HISTORIES 
found in the English "coal balls" 1 has disclosed both the 
microsporophylls, bearing pollen-sacs, and the megasporo- 
phylls, bearing, not merely megasporangia, but true seeds. 
The ovule has a pollen-chamber, like the cycads, except that 
it projects a bit through the micropyle, and, strange as it 
may seem, fossil pollen-grains have been discovered, well 
preserved within this chamber. The seeds, about y inch 
long, have been described as resembling little acorns, en- 
FIG. 418. Restoration of a seed of Lyginodendron oldhamium (Lagenos- 
tema Lomaxi), from a model by H. E. Smedley. (After Scott.) 
closed like hazelnuts in smaller glandular cupules (Fig. 
418). They are similar to those of the cycads, except 
that they are not known to have organized an embryo with 
cotyledons and caulicle. Instead, the tissues of the 
female gametophyte only are so far found, retained within 
1 Coal balls are "concretions of the carbonates of lime and magnesia 
which formed around certain masses of the peaty vegetation as centers 
and, through inclosing and interpenetrating them, preserved them from 
the peculiar processes of decay which converted the rest of the vegetation 
into coal. In them the mineral matter slowly replaced the vegetable 
matter, molecule by molecule, thus preserving the cellular structure to a 
remarkable degree. Such balls are especially frequent in the coal of 
certain parts of England (Lancashire and Yorkshire)." 
