64 



THE PLANT WORLD 



number has been correctly transcribed, as laxity in this regard 

 would be another fruitful source of fatal errors. Even with 

 the utmost precaution an occasional lapse will occur. The 

 proper proceedure then is to eliminate with a firm hand. 

 Perfect integrity and no guess-work are fundamental pre- 

 requisites of success and reliable results with the pedigree- 

 method. 



ACRES OF LIVERWORTS. 

 By Prof. Henry S. Conrad. 



Doubtless every bryologist knows of some spot where 

 he can find, or has found, the horned liverworts {Antho- 

 ceros) . I used to be told of a good bog at Woods Hole, 

 Mass. Another person had seen it beside a certain watering 

 trough out in the country near Philadelphia. It was with 

 some surprise, therefore, that I began a few years ago to find 

 Anthoceros in nearly every moist meadow, and beside every 

 spring and brook and wet ditch. By its dark watery green 

 color and slightly wavy surface, A. laevis may be certainly 

 recognized before the horn-like sporophytes have appeared. 

 When little wart-like antheridia are present, the identification 



is still more sure. 



In drier places one soon finds another Anthoceros. The 

 thallus is of a bright, often almost yellowish, green and the 

 surface Is covered with a forest of lobes and papillae. This 

 is Anthoceros pimctatus. 



Some time when hunting for A. laevis you find a circular 

 thallus one-quarter to one-half inch across, wrinkled at the 

 edges, and with tiny, yellowish, curved or straight sporo- 

 phytes projecting horizontally from their sheaths around the 

 margins of the thallus. This Is Notothylas orbicularis. We 

 find It very often, along with A. laevis. 



It was only by chance that I became acquainted with 

 Riccia. For years a single round and much branched thallu? 

 collected on a clayey brook bank was my only specimen. 

 Then R. crystallina appeared in two back yards in West 



