fee sh KA LED PEORA. 
Subkingdom PTERIDOPHYTA.* 
FERNS AND FERN-ALLIES. 
Plants containing woody and vascular tissues in the stem and producing 
spores asexually, which, on germination, develop small flat mostly green struc- 
tures called prothallia (gametophyte). On these are borne the sexual repro- 
ductive organs, the female known as archegones, the male as antherids. From 
the fertilization of the odsphere of the archegone by spermatozoids produced in 
the antherids, the asexual phase (sporophyte) of the plants is developed ; this 
phase is represented by an ordinary fern, lycopod or horsetail. 
This subkingdom comprises about 4000 living species, of which more than three-fourths 
are confined to tropical regions. The number of extinct species known probably exceeds 
those living. They appeared on the earth in the early part of the Palaeozoic Era, reached 
their greatest abundance in Carboniferous Time, but have since been mainly replaced by 
plants of higher organization, so that at present they form only about one-fiftieth of the 
total flora. The time of year noted under each species indicates the season at which the 
spores are mature. 
Family f. OPHIOGLOSSACEAE Pres], Pterid. 6. 1836. 
ADDER’S-TONGUE FAMILY. 
More or less succulent plants consisting of a stem and leaf growing from a 
fleshy root. Sporanges formed of the interior tissues, naked, borne in a spike 
or panicle and opening at maturity by a transverse slit. Spores copious, yellow. 
Prothallium subterranean, devoid of chlorophyll. 
Three genera, the following represented on both continents ; the third, Helminthostachys is 
native of southern Asia. 
Veins reticulate ; sporanges cohering in a distichous spike. 1. Ophioglossum., 
Veins free ; sporanges distinct, borne in spikes or panicles. 2. Botrychium., 
1. OPHIOGLOSSUM LI. Sp. Pl. 1062. 1753. 
Low plants from a small fleshy rootstock, with slender fleshy roots, the bud for the 
following year formed at the side of the base of the stem. Leaves solitary, borne on the 
stem, simple in our species. Spike terminal, formed of the two rows of large coalescent 
sporanges. Veins of the leaf reticulate. Spores copious, sulphur-yellow. [Name from 
the Greek, signifying the tongue of a snake, in allusion to the narrow spike of sporanges. ] 
About 10 species of wide geographic distribution. Besides the following, three others are 
found in the southern United States, one of them extending to California. 
* Text contributed by Professor LucIEN M. UNDERWOOD. 
I 
