370 
like coil, but further examination showed that the tube folded 
back and forth upon itself in such a way as to form a double 
layer. This peculiar growth was due in all probability to the 
meager amount of moisture in the anther, the folding serving to 
conserve moisture most effectively. Some tubes made as many 
as five double folds. Apparently the folding occurred after the 
tube had attained considerable length. 
Repeated examination of the pollen of both Arisaema triphyllum 
and A. Dracontium failed to afford another specimen in which ger- 
mination had taken place, and it seemed scarcely probable that 
this precocious development would occur frequently. It may 
have been due to the season or the situation; so far as I can see, 
it in no way benefits the plant. 
Warming, in his Systematic Botany, makes a group of mono- 
cotyledons which he calls the Enantioblastae, remarking that these 
plants ought perhaps to be amalgamated with the other orders. 
Although the Araceae are not included in this group, both species 
of Arisaema have truly enantioblastic ovules. The stigmas of 
Arisaema are remarkable in that the stigmatic surface not only 
covers the external surface of the capitate stigma, but extends 
down the short ofen style and forms a stigmatic surface at the 
summit of the cavity of the ovary, very much like the stigma om 
the outside of the ovary. The stigmatic hairs are club-shaped, 
quite long (short in the tube) and are not septate. They are 
closely packed together. The erect ovule reaches up to the hairs 
within the ovary. It remains to be seen just what the course of 
the pollen tube in these hairs is. It seems reasonable to suppo5¢ 
that the tube would enter the cavity of the ovary through the 
opening in the hollow style and that its entrance would be facili- 
tated by the stigmatic hairs. 
CORNELL UNIVERSITY. 
Explanation of Plates. 
PLATE 272. 
Fig. 1. Vertical section of consolidated stamens of Arisaema triphylium, show- 
ing anthers and anther-cavities, also structure of filament. (<125.) 
Fig. 2. Pollen grain. Fig. 3. Pollen grain germinated. Fig. 4. Pollen graim 
germinated, the tube closely folded upon itself. (Figs. 2, 3 and 4, <1400.) 
PLATE 273. 
Fig. 5. Vertical section of pistil showing ovules and stigma, (><350-) 
