5Q 



MUSCALES. 



[ACROGEAS. 



A remai'kable point of stiaicture in Liverworts is the spiral filament, or elater, as it is 

 called, l}ing among the sporules within the spore-case. This consists of a smgle fibre, 

 or of two, twisted spii-ally in different du'ections, so as to cross each other, and contained 

 within a very delicate, transparent, perishable tube. They have a strong elastic force, 

 and have been supposed to be destined to aid in the dispersion of the sporules, — a most 

 inadeqi\ate end for so curious and unusual an apparatus. It is more probable that they 

 are destined to fulfil, in the economy of these plants, some function of which we have 

 no knowledge. 



One of the most extraordinary points in tlie history of the Muscal Alliance, is the fact 

 that in the cells of the antheridia are generated bodies having what seems to be 

 spontaneous motion, and apparently of the same nature as the spermatic animalcules of 

 animals. This unexpected fact has been fully and correctly desci'ibed by Meyen, 

 (Ann. Sc, Nat. N. S. x. 319), who has found the same creatm-es (?) i^ ^^^e correspond- 

 ing organs of Chara and Mar- 

 chantia, Unger has also pub- 

 lished an elaborate Memoir 

 upon this smgular subject. 

 (Ann. Sc. N. S. xi. 257 and 274.) 

 He describes the spiral tlu'eads 

 of Sphagnum thus : — " These 

 animalcules consist of a thick 

 and swollen body having a 

 slender tlu'eadhke appendage. 

 The length varies between the 

 Fig. XXXV. 0.0025 and 0.0020 or ^i^ to 



^i_ of a line Vienna measure. The length of the appendage is about 4-^ longer than the 

 body, so that the total length of the anunal may be stated to be the 0.01 of a line." 

 It fs to be observed by those who may search for such bodies that they can only be 

 found just when the antheridium is completely formed, and that a magnifying power of 

 at least 600 diameters is requii'ed for theii' detection. Unger regards them as analogous 

 to the genus of animalcules called Spu-illum. It is so improbable that animals should be 

 generated in the cells of plants, vmless accidentally, that we cannot but entertain gi'ave 

 doubts whether, notwithstanding then* locomotive powers, these bodies are really any 

 thing more than a form of vegetable matter ; and it is worth considering if they may 

 not after all be a dimmutive representation of the clavate processes sm-rounding the 

 spore of Equisetum, and perhaps of the elaters fomid in the spore-cases of Liverworts. 

 This is certain, that the spores and elaters of Equisetum, when at rest, haA-e very much 

 the appearance of the Spirilla m the antheridium of an L'^rn Moss or a Chara ; and since 

 it has been proved that the spiral filaments of Equisetum arise from the splitting of a 

 cell in which a spore is generated, there seems no reason why a similar action should 

 not take place m cells that are destitute of spores. As to the motion, how are we to tell 

 that it is not a hygrometi"ical action ? There is as active a motion in the elaters of 

 Equisetum as m the spu'illa of ISIosses, only it arises in the former from di-ying and in 

 the latter from floating in water. Nageli has lately found the spiral threads of Liverworts 

 in the leaves of Ferns. 



Equisetum may be regarded as a hnk between this alliance and Chara on the one 

 hand, while its high degree of composition brings it into the neighbourhood of Ferns 

 and Clubmosses. 



By some Botanists the orders of the Muscal Alliance are separated into two great 

 groups, Hepaticae and Musci ; of which the former ai"e ^Wthout an operculum and have 

 for the most part elaters, while the latter have an operculum and always want elaters. 

 But such distmctions seem to be of hardly sufficient importance to be employed for 

 higher purposes than the distinction of Natural orders. 



Natural Orders of Muscals. 



1. Hepatic^. 



Spore-cases ralveless, witliout operculum or elaters . . 15. Ricciace^. 



Spore-cases ralveless or bursting irreqularly, without] ,^ -.^ 



operculum, but with elaters ^ . ...... . 1 16. Marchantiace^. 



Spore-cases openinq by a definite number of equal xalves. 1 , - t 



without operculum, but with elaters ... . . .]^^- Ju^geRManniace^. 



Spore-cases peltate, splitting on one side, without oper- "1 , p p 



cxdum, and with an elater to every sp>ore . . . . J -C^QUISEtace^. 



2. Musci. 



Spore-cases opening by valves, with an operculum, ^vith- "I , ^ . 



out elaters J ^^' ^^^^^^cem. 



Spo7'c-cases vaJveles.'^,u-ith an operculum, with otd elaters . 20. Bryace^. 



