FOES IN THE HAYFIELD. 95 



The rattles are a whole group of half -developed para- 

 sites well on the way to the worst stage of degradation , 

 though not yet so utterly degenerate as the leafless tooth- 

 worts or the scaly broomrapes. They can still grow 

 feebly if left to themselves ; for when you sow the seeds 

 alone in a flower-pot, by way of experiment, the young 

 seedlings will rise to an inch or two, put forth a few 

 scrubby leaves, and blossom poorly with a couple of 

 straggling flowers or so. But when you let them have 

 some nice vigorous grass-plants in the same pot, they fix 

 upon them immediately, and grow to a foot in height, 

 with a comparatively fine spike of pale primrose flowers, 

 which children sometimes know as cockscombs. Eye- 

 bright has just the same trick ; and so have the two red- 

 rattles, cow-wheat, and others of their kind. There are 

 some parasites, like mistletoe, whose parasitism has be- 

 come so deeply ingrained that their seeds will not even 

 sprout except on the body of a proper host ; and these 

 have adapted themselves to their peculiar habits by ac- 

 quiring very sticky berries, which fall on a bough, and 

 are gummed there by their own bird-lime. Even such 

 a hardened offender as the mistletoe, however, has par- 

 tially green leaves which assimilate food on their own ac- 

 count. But there are other and still more abandoned 

 parasites, like yellow bird's-nest, which have no leaves 

 at all, and cannot provide themselves with food in any 

 way. Yellow bird's-nest is a very rare plant in England 

 a degraded relation of the heaths, which has taken en- 

 tirely to living on the roots of trees, sucking up their 

 juices by its network of succulent rootlets. Its leaves 

 have consequently shrunk by disuse into mere pale yel- 

 lowish scales, not unlike those which one sees on the 

 young shoots of blanched asparagus. Now, yellow-rattle 

 and its kind deserve notice as showing the first step on 



