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Devonian), and by the production of "synthetic lichens," in the 

 laboratory by European experimenters, where lichen spores, 

 sowed upon suitable algal cells, in culture media have germi- 

 nated into lichens resembling the parents. Readers are referred 

 to Annie Lorain Smith's book for a very full account of the 

 history of the development of knowledge concerning lichens. 

 Her two volume "British Lichens," is also valuable for identifi- 

 cation of many cosmopolitan species found in both the old 

 and new worlds. A condensed edition is also available. 



To place the Cladoniae, it may be said that lichens in general 

 are of three kinds; crustose, growing closely upon rocks, bark 

 or earth; such as Lecidea albocaerulescens , to name a common 

 species in our range, with bluish-gray thallus looking almost as 

 if painted on rock; foliose, leaf-like, such as the familiar Rock 

 Tripes, or Parmelias; and fruticose, shrublike or branching, of 

 which the Cladonias, and especially such densely branching 

 forms as the "Reindeer Mosses," are typical examples. 



A Cladonia plant is usually erect, with distinct stems, simple 

 or branched, and often with conspicuous fruit, to use an easily 

 understood term; such as, for example, the familiar Scarlet- 

 crested Cladonia, occurring everywhere in our range, and one 

 of the first lichens to attract the attention of young nature 

 students, because of its brilliant color. In height Cladonias 

 range from tiny species like C. papillaria, mitrula, brevis and 

 cariosa, 1/4 to 1/2 inch tall; to C. gracilis and C. rangiferina, 

 three or four inches tall in our range, and the latter a foot high 

 in northern regions. In area colonies sometimes cover several 

 acres. 



To be more precise in terms, the Cladonia plant usually 

 shows two distinct parts, the primary thallus, of scale-like 

 leaves, from a size no larger than the head of a pin to an inch 

 long in different species, prostrate or somewhat raised, some- 

 times densely aggregated into a crust; and the podetium, the 

 erect portion on which the apothecia, or spore-producing 

 organs, are borne. The podetium is regarded as a sort of second- 

 ary thallus. 



Both primary thallus and podetia contain algal cells, just 

 under the surface, spherical and bright green when moist, which 

 are usually identified as in the genus Cystococcus. They are 

 enmeshed by the hyphae, thread-like processes extending from 



