464 PARTHENOGENESIS. 



Ltibeck, the neighbourhood of Warnemunde near Rostock, the two Jasmunder Bod- 

 dens (inland branches of the sea), on the island of Rugen, and the Wanger Wieck 

 near Stralsund, where Chara crinita is exceedingly plentiful, have been repeatedly 

 searched for male plants but in vain. And the female plants also have been 

 examined in case, perchance, an occasional antheridium might occur upon them, as 

 in the monoecious species of Chara. Thus we may take it as established that in 

 the Baltic region no antheridia and consequently no spermatozoids are developed. 

 Nor was the attempt successful to explain the matter on the supposition that at 

 the time of fruiting spermatozoids were brought by water-birds from Hungary, the 

 Caspian, or the South of France. In the Baltic the egg-cells of Chara crinita 

 remain unfertilized in their oogonia; the latter fall off in autumn and, without 

 stimulus from any spermatozoid, germinate in the spring. We have here an 

 instance of what Zoologists have termed Parthenogenesis. It has been demonstrated 

 with certainty that new individuals arise from unfertilized eggs in the Spruce-gall 

 Aphis (Chermes), in plant-lice (Aphis), and in many bees, wasps, &c. Also, in the 

 Silk-worm Moth and in Solenobia, larvae arise from unfertilized eggs and these 

 pupae give rise only to females. This is of interest in that from the unfertilized 

 oogonia of Chara crinita only individuals with oogonia arise. 



Cases similar to Chara crinita are thought to exist in several plants found in 

 water or on moist substratums. In the genus Syzygites (now included in Sporo- 

 dinia), a mould-like Fungus belonging to the Mucorini (cf. p. 54), the protoplasm 

 in the conjugating branches forms the starting-point of new individuals without 

 any actual fusion or conjugation taking place. So also in the Saprolegniaceae it 

 often happens that the egg-cells in the oogonia form new plants without being 

 fertilized; probably renewed investigations will bring to light similar relations in 

 many Peronosporeae, Siphonaceae, &c. 



Amongst the Mosses parthenogenesis does not seem to be so very rare. In 

 them, as in Characeae, fertilization is accomplished by means of water; the plants 

 are wetted by rain and dew, and this moisture is held by capillarity in the chinks, 

 fec., between the leaves. The fertilizing spermatozoids travel some distance, swim- 

 ming through the water to reach the archegonia. This distance is not very great 

 in many forms, and these ripen their fruits freely. But there are several species 

 in which only male plants occur in one locality and female plants in another 

 it may be hundreds of miles away. Such species are Paludella squarrosa, which 

 occurs in North Tyrol with antheridia, and in Bohemia with archegonia only; 

 Grimmia Hartmanni, found in the Alps with antheridia, and in the Carpathians 

 with archegonia. Neckera Besseri, Aulacomnion turgidum, Bryum alpinum and 

 B. Duvalii, Didymodon ruber, Barbula recurvifolia, Amphoridium Mougeotii, 

 Mnium insigne, Pterogonium gracile, Hypnum rugosum, and Thuidium abie- 

 tinum are further examples of which we cannot treat here in detail. As it is 

 impossible for the archegonium of a Moss in the Carpathians to be fertilized by 

 a spermatozoid from an antheridial plant in the Alps, and as fruits are ripened 

 nevertheless, though not very abundantly in truth, it may well be that these are 



