FRESHWATER ALG.E. 



193 



For example : the slii? being so arranged that the left liaud l-lOOOth 

 line corresponds accurately with one of those on the eye-piece, suppose 

 that the 5th hne of the eye-piece corresponds with the 9th 1-lOOUth line 

 from the left on the shp. Hence five divisions of the eye-piece = 9-lOOOths 

 or 1 division = 9-500Uths =: l-555th of an inch. In this manner the 

 actual value of one division of the eye-piece for each poxcer should be 

 registered once for all : it is then the work of a moment to record the 

 actual dimensions of any object under examination. 



If Buch records were kept systematically by observers, a comparison 

 of their observations would go far to f acihtate a harmonious classification 

 of a large and beautiful tribe of plants, the bibliogi-aphy of which is at 

 present most unsatisfactory, and has suffered grievously from a needless 

 multij)lication of supposed species, consequent upon imperfect observa- 

 tions still more imperfectly recorded. 



The object of this paper wiU be amply fiilfiUed if it induces some of 

 the Naturalists of the Midland counties to engage in the study of these 

 minute organisms, and to do their share towards elucidating the many 

 points in their physiology which are still obscure. 



ON THE STUDY OF THE MOSSES.— H. 



BY JAMES E. BAGNALL. 



In my last paper (page 59) the inaterial and apparatus required for 

 the collecting and study of these plants were treated of. In the present 

 I purpose giving some account of the development of Mosses. 



Mosses are cellular plants, having distinct stems, leaves, and roots, 

 (the Sphagnums or bog-mosses are exceptional, as they do not possess 

 roots;) they have a capsular fruit, and are developed from spores, (seed- 

 like contents of ripe capsule, Plate IV., fig. 1,) or gemmse, (cellular bodies 

 capable of hecomlng plants, fig. '2d.) 



Desckiption of Figuees. — Plate IV. 

 1.— Spores of moss. 

 2. — Gemmiforrn state of Aulocomnion, a stem, b stalk, c gemmaj, d gemma 



detHched and magiiitied. 

 3. — A protoubnia, 6i< youug mossplauts. 

 4. — Species of Pottia, to show terminal fruited moss, a stem, b fruitstaLk, c capsule, 



d conical lid. 

 5.— Species of Hypnum, to show lateral truited moss, a fruitstaLk, b capsules. 

 6. — Leaf of Hypnum, to s-liow nerve, a nerve, b margin. 

 7.— Male flower of moss, a Antlieridium, throwing off a number of Antherozoids c, 



bb iiaraphyses. 

 8. — Antherldium of Sphagnum. 



9. — Aiche^;onium of moss, a neck, b pear shaped body, c germ cell, d canal. 

 10.— Fruit rudiment, a calyptra, b rudimentary fruilstalk, c vagiuula. 

 11. — Indeshiscent capsule of Fhaiscum, a capsule, b fruitstalk, o vaginula. 

 12. — Simple peristome of Tetraphis, a conical operculum, b jjcristome, c capsule. 

 13. — Strumose capsu e of Dicranum falcatum, a rostrate operculum, b struma. 

 14. — Capsule of Splachnum, a operculum, '< capsule, c apophysis. 

 15. — Proseuchymatous cells from leaf of liryum. 

 16. — Parenchymatous cells from leaf of Pottia. 

 17. — Inflated dimidiate calyptra of Funaria. 

 18. — Dimiiiiate calyptra of Tortula. 

 19. — Capsule of Andrea:a, dehiscing by valves a a. 



20. — Part of double xieristome of Hyfjimm, a muer peristome, b outer peristome, 

 21. — Capsule of PuLytriclium, a capsule, b peristome, c diaphiagm. 



