36 THE AMERICAN BOTANIST. 



roughly compared with the seventeen-year locust, which ap- 

 pears so suddenly after a long interval of years. 



The habit of lying dormant is known to be true of some 

 orchids, and is illustrated by some definite cases near Urbana. 

 The white fringed orchids, Habenaria lencophaca or Blcphari- 

 glottis leucophaca, formely grew in a swampy place near there- 

 A railroad track destroyed the habitat, except a strip about a 

 hundred feet wide and five hundred feet long. The orchis 

 bloomed there in 1893, and, although careful search was made 

 each following year, it was not seen again until 1900. For the 

 four succeeding years the place was watched with great care, 

 but the orchis never appeared, and in 1905 the station was de- 

 stroyed by filling in with cinders. In 1901 the nodding po- 

 gonia, called variously Pogouia pcndnla, Pogonia triantho- 

 phora, and Triphora trianthophora, bloomed in the Brown- 

 field woods, northeast of Urbana. The location of the rotten 

 log on which it grew was carefully marked, and the place 

 watched during the following years. It has not reappeared, 

 but if it follows a seven-year rotation, as Habenaria apparently 

 does, it might be expected again this summer. These woods 

 are familiar to all the botanists of the vicinity, and have been 

 for years, yet not until this spring was putty-root, {Aplcctnim 

 spicattim), found there. It had bloomed there last year, but 

 in some way escaped notice. 



Each of these three cases concerns species that are very 

 rare or local in the vicinity and of which but few individuals 

 have ever been seen. More remarkable in some respects than 

 either of the three is the case of squirrel-corn {Diccntra cana- 

 densis). Many years ago it was found in the Brownfield 

 woods. The writer was told of its occurrence there, and, be- 

 ginning in 1899, searched those woods every spring for six 

 years without finding it. One year he systematically examined 

 a thousand or more plants of Diccntra, all of which proved to 

 be the Dutchman's breeches, {Diccntra CucuUaria). Last 



