AND HEPATICOLOGY OF NORTH AMERICA. 61 



It may be here noticed, that the position and structure of the 

 male flower of P. patens has been incorrectly described and figured 

 by authors as terminal, and borne upon proper branches arising 

 from the base of the main stem. Such is by no means the case. 

 The male flower, as in Schistidium serratum, is situated near the 

 female, rarely mixed with it, in the axils of the floral or upper 

 leaves, either of the main stem or its innovations ; the antheridia, 

 3 - 5 in number, are accompanied by paraphyses with globose ter- 

 minal cells ; and rudimentary perigonial leaves are occasionally 

 present. All the North American specimens of P. patens, so called, 

 that have come under my observation, belong to immature states 

 of Schistidium serratum; but future examination may show that 

 the two plants are less distinct than is at present supposed. 



Our plant, as now understood, cannot be referred to the genus 

 Schistidium of Bridel, much less to that of Bruch & Schimper; nor 

 does it agree with any other well defined genus. With Physco- 

 mitrium, Br. ^ Sch., it has many characters in common, and, in 

 fact, the position of the male flower presents the only essential 

 point of disagreement. 



The plant is annual, and is often met with in the Middle and 

 Western States, on rich soil, particularly near the margins of 

 streams subject to inundation ; it fruits during the summer and 

 autumnal months. 



Tab. II. C. — Fig. 1. Plants of the natural size. Fig. 2. Part of a 

 plant, showing the capsule, operculum, and the position of the male flowers. 

 Fig. 3. Spores. Fig. 4. Calyptra. Fig. 5. Antheridia with paraphyses. 

 Fig. 6. Plant with a simple stem. Fig. 7. A portion of leaf. Fig. 8. A 

 plant with innovations. All magnified. 



