360 Goebel . — On the Simplest Form of Moss. 
with those of the sporophyll in the lower. Directly the 
abortion of the sporangia is induced, the sporophyll at once 
exhibits the characters of a foliage-leaf. 
At present I can see in the sporophylls of Ophioglossum 
and of Helmin thostachys nothing more than very highly 
modified portions of leaves. In Ophioglossum the sporangia 
are imbedded in the sporophyll, whilst in Helminthos tacky s 
and Botrychium they are superficial, a difference which finds 
its parallel in that which exists between the highly modified 
stamens of the Angiosperms with their imbedded pollen-sacs 
and those of the Cycadeae with superficial pollen-sacs which 
present some external resemblance to the sporangia of the 
Vascular Cryptogams. Moreover, in Ophioglossum palmatum 
the sporophylls are still clearly recognisable as leaf-segments. 
EXPLANATION OF FIGURES IN PLATE XXII. 
Illustrating Professor Goebel’s paper on the Simplest Form of Moss. 
Figs. 1 and 2. Botrychium Lunaria, two pinnae of the sterile portion of the 
leaf on which sporangia ( sp ) have made their appearance. 
Figs. 3-5. Onoclea Struthiopteris, a sporophyll artificially converted into a 
foliage-leaf. 
