FERNS AND THEIR RELATIVES 89 
spots to be searched, and the fern may be found lying 
inconspicuous among the grass. 
The Adder’s Tongue is the third of these eccentric 
ferns, and perhaps the rarest. Damp meadows are its 
favourite resort. The frond splits into two parts, as in 
the Moonwort, but the green, unfertile half remains 
entire, pointed at the tip and egg-shaped at the base. 
The fertile section is upright, but, unlike the Moonwort, 
it does not branch at all, the spore-cases being arranged 
in a double row along its upper half. 
I have called this chapter “ Ferns and their Relatives,” 
and these relatives deserve a closer study on your part 
than we can give them here, for, though not interesting 
in appearance, in some of their methods they lead us 
és on to the flowering plants, and illustrate 
the development from one class to the 
other, and the absence of sharp and 
definite boundaries to which I have more 
than once drawn your attention. First 
come the Horse- tails, which you wili 
recognise at once from the illustration. 
They all go through the double generation 
we saw in the ferns; first the flat ‘“ pro- 
ffir,’ . thallium,” and then the branching “plant.” 
SNP = The horse-tails have adopted the separa- 
“f¢ So tion of the spore business from ordinary 
: vegetation. Special spikes run up in the 
spring, usually before the rest of the plant 
appears, with very little trace of the usual 
\y whorls of branches at the joints, and 
, headed by groups of spore-cases. Their 
Sx work done, and the spores spread, the 
ordinary shoots come up. Now the whorls 
~ 
HORSE-TAILS. 
