GENERA AND SPECIES. 147 
PLare LYxX. 
OPHIOGLOSSUM. Linnzus. 
ADDER’S TONGUE. 
GEN. CHAR.—Sporangia sessile, naked, coherent in two ranks; 
fronds with sterile and fertile segments, the former simple, ovate, 
oblong—the latter forming a simple spike; veins reticulated. 
This is the typical genus of the sub-order Ophioglos- 
sacee. The distinctive characters of the genus are some- 
what like those of Botrychia. The sporangia, however, 
instead of being arranged in the form of a compound pan- 
icle, occupy a simple spike. ‘These sporangia or spore- 
cases are sessile, and situated near the apex of a long cylin- 
drical stem, in two ranks. The spore-cases are opaque, 
discharging, when ripe, a number of minute spores from 
a transverse slit, forming two valves. 
According to Hofmeister, the young frond makes its 
appearance near the depressed, almost flat end of the stem, 
in the form of a slender conical knob, from the fore side 
of which a fleshy, flat, stipule-like excrescence, as in Ma- 
rattia, is produced. This cellular mass develops in breadth 
more vigorously than the part of the frond which is situa- 
ted above its place of attachment. It embraces about 
two fifths, and the frond about one third of the zone of 
the stem upon which they both stand.* The sporangia of 
Ophioglossum agree with those of all the Vascular Cryp- 
togams in the one point of belonging to the leaves, although 
the history of their development is not as yet accurately 
known (Sachs). Figure 1 of the Plate is from nature; fig- 
ures 2, 3, and 4 are from Hooker and Bauer. 
* See Hofmeister, 1. c. p. 312. 
