July 1, 1898.] 



KNOWLEDGE 



165 



which is closed in early stages by a lid, and subsequently 

 by a special structure, the peristome. 



From a physiological point of view the stomata and 

 chlorophyll grains of the moss sporophyte are of no less 

 importance. Knowing, as we do, that these structures 

 are constantly associated with active and indepcndnit 

 plant life — its respiration, nutrition, and metabolism — it is 

 evident that the sporophyte of the moss has advanced much 



of a moBS. Again, in the curious minute mosses such as 

 Epiiemerum the protonema persists throughout the life of 

 the plant — an apparently archaic character. 



The strange Bu.rbnumia, with its rudimentary leaves and 

 partly persistent protonema, its reproductive organs rising 

 (as Prof. Goebel has shown) almost direct from the pro- 

 tonema, suggests at first sight a very primitive type of 

 moss. Yet its capsule is large and specialized in structure, 



A. — The Spore. B. — Commencement of germination of the Spore, c. — Later stage; the Spore is throwing out a green 

 protonemal Filament on the left, and a colourless Bhizoid on the right. D. — Protonema of Mniitm, with a lateral Bud which 

 will grow into a Moss Plant. (Magnified.) E. and f. — Male and female Plants of Milium hornum, var. (Natural size.) 

 G. — Section through the male ■' Flower." (Enlarged.) H. — Antheridia and Paraphjses of Milium afflne. The Antheridium 

 on the left is empty ; that on the right is discharging its contents, Spei-matozoids in their Capsules, embedded in mucilaginous 

 material. I.— Spermatozoiil enclosed in Capsule. K. — Free Spermatozoid. L. — Archegonia and Paraphyses of J/n!'Ki« c_^«?. 

 The Archegonium on the left is not vet fertilized ; that on the right has been fertilized, and the Cospore has begun to divide 

 to form the young Sporophyte. ir. — Plant of Mniuin ajfiiie, yar., shoning young Sporophyte. N. — The same at a later 

 stage, showing the Calyptra carried up. o. — The same, showing deyeloped Capsule shedding the CaWptra. p. — The same at 

 the ripe stage dropping the Operculum. Q. — Diagrammatic section through the apex of the stem and the base of the Sporophyte, 

 showing the latter embedded in the parent tissue, and the withering Archegonia and Paraphvses round its base. B. — Diagram- 

 matic longitudinal section of the Capsule, showing the Columella (c) ; the Archesporium (ac); the Air Space (<z-«) ; the 

 Annulus («) ; the Peristome (jl>) ; and the Opercidum (o). s. — The Peristome seen from above, with the sixteen outer teeth 

 turned back. The mouth of the Capsule is still closed by the inner Peristome, consisting of an outer or basal membrane, 

 sixteen pairs of teeth opposite the outer ones, and sixteen pairs of cilia alternating with tliem. T. — Teeth and cilia of the 

 inner Peristome, u.— One of the outer Peristome teeth. 



further than that of the Liverwort towards establishing its 

 claim to be a separate plant. We have no evident link 

 connecting the Liverworts and the mosses. The little 

 mountain moss, Amlncea, is peculiar in possessing a 

 capsule which bursts into four segments. Unlike the 

 Junijermanniii, the segments remain joined at the apes, 

 and the general structure and habit of the plant are those 



and may be a degeneration from some higher form rather 

 than a representative of an ancestral stage. It is, in 

 fact, impossible to say what is the lowest and simplest 

 type of moss ; and it is safer to regard the Liverworts 

 and mosses, with their several aberrant relatives, as 

 separate modifications descended from some type we have 

 lost. 



