Osborn . — Some Observations on Isoetes Drummondii , A.Br. 43 
their dry laminae may persist for some weeks, but ultimately become 
detached from the base somewhat below the soil level. Hence, in summer, 
plants can hardly be found even by careful search of small areas in which 
they are known to occur. 
There is thus left below ground, during the dry season, the stock, 
bearing on its upper surface the somewhat cone-shaped mass of sporophyll 
Fig. 2. Plant collected at the opening of the vegetative season. The upper leaf-bearing surface 
of the stpck shows a clear ring between the scales that surround the young leaves and the outer 
withered bases of the previous season’s sterile leaves, two of which are shown reflexed. Two of the 
lobes are visible, the ‘ scar surface ’ stippled. The roots are cut off close to the groove. x 3. 
Fig. 3. Plant collected in June at the stage of elevating the old sporophylls. The mucilage 
tissue at the bases is much swollen by water (cf. Fig. 2, which was drawn at the same time from 
a similar plant from which the mucilage and sporophylls had been removed), x 3. 
• Fig. 4. Dry projectile-like mass of imbricate sporophyll bases, collected on surface of soil in 
June. Below it two dry contracted masses of mucilage can be seen, x 3. 
bases and the withered roots which dry up and die off completely at the 
beginning of the dry season. This condition persists for from four to five 
months. The stock has a hard brown coat formed of the sclerized outer 
cells over the whole of its surface, and the depressed apex is roofed over 
by three or four triangular imbricating scale-leaves, the cells of which are 
sclerized. 
