500 



SCIENCE 



[N. S. Vol. XXVII. No. 691 



into range in doing so. This may sound easy, 

 but if so, the reader is likely to alter his 

 opinion after reading Herr Schillings's inter- 

 esting narrative. We should have omitted all 

 the illustrations of " failures " of one kind or 

 another, as quite unnecessary to the descrip- 

 tion of the methods. 



The translation seems to be well done, and 

 but few and trifling errors have been noticed. 

 The moral of the work, like the matter of it 

 is admirable, and may be expressed in brief — 

 avoid all ruthless and unnecessary destruction 

 of the beauties of nature wherever foimd! 



Francis H. Herrick 



Aposporie et SexualUe cliez les Mousses. El. 



and Em. Marchal. Bull. Ac. roy. Belg. CI. 



Sciences, No. 7, pp. T65-Y89. 



In a paper already reviewed in Science, the 

 Marchals have shown that the individual cap- 

 sules of certain dioecious mosses contain both 

 male and female spores and that regenerations 

 from the leaves, protonemata or from other 

 parts of the gametophyte give rise to the same 

 sex as the plant from which they were derived. 

 In the present paper they give the results of a 

 careful investigation by means of pure cul- 

 tures of the sexual condition in the sporo- 

 phytes of the dioecious mosses — Bryum 

 ccespiticium, Mnium hornum and Bryum 

 argenteum. They find that regenerations 

 from the capsule or from its stalk, i. e., from 

 any part of the sporophyte, give rise to bi- 

 sexual protonemata from each of which are 

 developed three types of leafy axes : (1) Those 

 apparently male containing only antheridia, 

 (2) those obviously hermaphroditic contain- 

 ing both antheridia and archegonia, (3) those 

 apparently female containing only archegonia. 

 Shoots with only antheridia were most com- 

 mon, those with both antheridia and arche- 

 gonia were considerably less abundant while 

 those with only archegonia were distinctly 

 rare. That the three different types of shoots 

 were potentially hermaphroditic was shown by 

 regenerations from their leaves. These gave 

 in repeated cultures of Bryum cwspiticium ap- 

 proximately the same ratio of shoots appar- 

 ently male, hermaphroditic and female as were 



obtained directly by regeneration from the 

 sporophyte and it is concluded that the 

 hermaphroditic condition can be thus indefi- 

 nitely propagated by vegetative means. 



It may be pointed out that this transforma- 

 tion of a dioecious species of the mosses into 

 an hermaphroditic growth brought about by 

 the Marchals is similar to what the reviewer 

 has already accomplished in essentially the 

 same manner with the mould Phycomyces 

 nitens. The hermaphroditic growth obtained 

 from this species when propagated by cuttings 

 retains its bisexual character often to a dozen 

 or more vegetative generations but eventually 

 the bisexual character is lost and with the 

 disappearance of one sex, the growth is not 

 to be distinguished from a pure unisexual 

 race, male or female as the case may be. The 

 hermaphroditic growths of the mosses resemble 

 those of Phycomyces in that they differ in 

 their sexual polarity. Thus while one re- 

 generation from the sporophyte of Bryum 

 cwspiticium showed a marked male polarity 

 and produced one shoot with antheridia and 

 archegonia to 51 with only antheridia, a 

 second regeneration from the sporophyte of 

 this same species showed an equality of the 

 sexes and of 21 shoots, produced lY with arche- 

 gonia and antheridia, 2 with only antheridia 

 and 2 wifh only archegonia. In view of the 

 behavior of Phycomyces, the Marchals seem 

 hardly justified in concluding from an exami- 

 nation of only two generations that the herma- 

 phroditic condition obtained in the mosses can 

 be propagated for an indefinite period. 



A determination of the chromosome num- 

 ber and the sexual conditions which result 

 from the union of gametes arising from their 

 artificially produced hermaphrodites is prom- 

 ised by the Marchals in the near future. 



Mention of some unpublished work on the 

 zygospores of Phycomyces may not be out of 

 place in this connection. Zygospores formed 

 by hermaphroditic growths of this species, 

 which the reviewer has recently brought to 

 germination, do not differ, in the sexual rela- 

 tions of the offspring to which they give rise, 

 from zygospores formed between dioecious 

 growths. It seems impossible therefore to fix 



