Nov. 1, 1867.] 



HARDWICKE'S SCIENCE-GOSSIP. 



249 



("Entomological Text-Book," p. 3S9), in which the 

 saucer-like cup and hall' of the envelope only had been 

 completed, leaving the cells exposed (see Westwood, 

 Introd., vol. ii., p. 250). This wasp is included in 

 Saussure's "Guepes Sociales" (p. 122) under the 

 name of Vespa sylvestris, hut the nest is not figured. 



Charles II. Griffith. 



THE ORGANIZATION OF MOSSES* 



By R. Braithwaite, M.D., F.L.S. 



FN former times many of the smaller cryptogamic 

 -■- plants were termed mosses, and although no 

 order of plants is better defined or more readily 

 recognized, the name is still vulgarly applied to 

 lichens, as Iceland Moss, Cup Moss, and the 

 shaggy forms growing on old trees ; to Algse as 

 Irish Moss ; and even to some fungi. But the 

 plants we have to consider are the mosses par 

 excellence, Musci veri, or frondosi, as they have 

 been termed, to distinguish them from the Musci 

 hepatici, or Liverworts. 



By the ancients this group was but little regarded, 

 for then plants were sought after on account of their 

 real or supposed medicinal virtues ; yet they had a 

 Muscus cranii humani, or moss of a dead man's 

 skull, which no doubt in the days of signature medi- 

 cine was found of great service in head complaints. 

 The first special work on the subject is the Historia 

 Muscorum of Dillenius, published in 17-11, remark- 

 able for the excellence of its engravings, and con- 

 taining also lichens and algse. 



Linnaeus enumerates many mosses in his Species 

 Plantarum, but he seems to have paid little attention 

 to cryptogamic plants, and hence often confounded 

 them. His erroneous notion that the Capsule was 

 an anther, and the spores pollen, led his followers 

 astray, though we may chiefly attribute it to the 

 want of sufficient optical assistance. 



John Hedwig, however, now gave to the world 

 those great works which have rendered his name 

 immortal, and fully entitle him to rank as the founder 

 of Bryology. He was undoubtedly the first to dis- 

 cover the sexual organs in these plants, and his clear 

 diagnosis of species is indicated by the great number 

 which still bear the names he imposed. 



These w r ere followed by the valuable Bryologia 

 Universa, and other works of the learned Bridel, 

 whose critical eye greatly augmented the number of 

 species ; and in our day Wilson, aud Mitten, and 

 lastly Professor Schimper have immensely extended 

 our knowledge of them, the Bryologia Europsea of 

 the last named author being the grandest contri- 

 bution ever made to a single department of botanical 

 study. 



* Read before the Quekett Microscopical Club, June 28th. 



Bridel heads the first chapter of his Muscologia 

 Recentiorum with the query, "Quid sit muscus?" 

 (What may a moss be ?), and this I hope you will 

 be able to auswer, after becoming acquainted with 

 the details of their structure. 



The mosses, to a cursory observer, may appear 

 uninviting from their minuteness and apparent simi- 

 larity, yet when we call the microscope to our aid, 

 the exquisite beauty of their structure is at once 

 apparent. They are entirely cellular, and is it not 

 surely a subject for admiration, that by mere diver- 

 sity in form, arrangement, and construction of cells, 

 we are able to characterize near 9,000 species in this 

 one class of plants ? 



The Seed or Spore. — This is very minute, yet vary- 

 ing in diameter between i and T £o of a millimetre ; in 

 some minute mosses it is of large size, the capsule 

 containing only ten or twenty spores; 1 in others 

 it is very minute, and innumerable. The spore 

 is globose, of a yellow, rufous, or brown colour ; 

 its surface smooth or covered with rough points, 

 and it consists of a mother cell, or primordial 

 utricle, enveloped hi an outer coat, or exospore, the 

 contents being chlorophyl, starch, and oil globules, 

 with mucus. 



The first result of germination is the rupture of 

 the outer coat, and protrusion of the primordial 

 utricle or cell, which immediately commences divi- 

 sion, the new cells repeating the process, until a 



Fig 253. Spore of Funaria 

 hygrometrica. 



Fig. 254. Spore of Funaria 

 hygrometrica germinating. 



Fig. 255. Prothallium and young plant. 



dense felt of branched confervoid threads results, 

 which we term the prothallium, and forming the 

 green film we may often notice in / spring coating 

 damp walls and banks, and long mistaken for species 

 of algae (figs. 253, 254, 255).- From various cells of 

 this young plants are developed, whose fine radicles 

 penetrate the soil ; their leaves shoot up, and they 

 become like the parent from which the spore ema- 

 nated ; and being now capable of maintaining an 

 independent existence, the prothallium, no longer 

 needed, dies away, except in a few minute annual 



