184 MORPHOLOGY. 



a few other facts, appears to offer an indication of a parent cell always 

 giving origin to two or four new cells, and that consequently in a limited 

 but uninterrupted formation, the cells formed and the equally definite 

 groups of cells must be almost regularly divisible by two or four. There 

 is certainly nothing beyond an indication to be looked for here, and it 

 would be mere empty play to attempt erecting an influential law upon 

 so frail a foundation. There are, besides, many deviations to be met 

 with in the development of the sporocarp. In the Sphagnum the pro- 

 truding archegonium breaks through the calyptra in an upward direction 

 instead of tearing it away from the base, but it does not form any long 

 seta. In the so-called Astomi the upper and middle part of the archego- 

 nium becomes developed into a simple, entirely closed capsule, only subse- 

 quently irregularly torn open, as, for instance, in Phascum. The amount 

 of cellular tissue that remains as a columella is also very variable, so that 

 sometimes there is scarcely a trace of it to be found in the ripe sporocarp. 

 In Andrecea a simple capsule is formed, which is rent lengthwise into 

 four lobes, which remain united at the apex and base. Finally, in a great 

 number of the Mosses the upper third portion of the archegonium forms 

 merely the operculum, without being further heterogeneously developed 

 inward : all these, consequently, are devoid of a peristoma. Meyen pre- 

 tends to have seen spores formed in Sphagnum at the end of a cellular 

 filament by the spontaneous separation of a parent spore, as in Liver- 

 worts. I have never been able to find these filaments, but I have easily 

 succeeded in pressing out four perfectly free spores in a young condition 

 from the parent cell (sporangium) in which they were enclosed. Finally, 

 we meet with a deviation in some Polytrichoidece, where four plates of 

 dense cellular tissue remain between the inner membrane of the theca 

 and the columella, dividing, until the sporocarp is nearly mature, the 

 space destined for the spores into four parts. Many other interesting 

 particulars may be found on this subject in Robert Brown's works * ; 

 we have also recently obtained very excellent contributions on the de- 

 velopment of the spores by Lantzius-Beninga. j The most important re- 

 sult of the latter work is the fact that the layer of the archegonium, from 

 which the spores are subsequently developed, consists originally only of 

 a single layer of cells, which are parent cells. Meyen says (in his 

 Physiologic, vol. iii. p. 387.), " Robert Brown appears to have been of 

 the opinion that the spores of Mosses are formed in the cells of the colu- 

 mella." Palisot de Beauvois had asserted that the true spores were 

 formed in the columella, and that the loose granules deposited around it 

 were the pollen. Robert Brown's assertions are directed against this false 

 view, which he fully sets aside in his usual sure and profound manner. 



D. Little buds similar to those mentioned at A, or disc-shaped 

 as in Potytrichum, Splachnum, contain another peculiar organ (an- 

 theridium), which, as in the above mentioned, also occurs with 

 archegonia even in the same blossom. The earliest condition in 

 which it has as yet been observed exhibits a small ellipsoidal, 

 longer or shorter pedicled, cellular corpuscle, having a dark opaque 

 spot in the interior. Somewhat later, we may definitely distinguish 

 a simple layer of cells, enclosing a large central cell, filled with 

 turbid formative matter. Here we subsequently find cytoblasts, 



* See R. Brown's Miscellaneous Works (loc. cit. II. 682 744-). 



f De Evolutione Sporidiorum in Capsulis Muscorum. Gottingen, 1844. 



