56 TRANSACTIONS, NATCKAL HISTORY SOCIETY OF GLASGOAY. 



prothallus, it is insured that at least some of them 

 will reach the germ-cells they are intended to 

 fertilise. Such locomotive antherozoids are pro- 

 duced by Ferns, Horsetails, Lycopods, Liverworts, 

 Charas, most AlgJB, and many Fungi. The Floridese, 

 or Red Seaweeds, form an exception ; the anthero- 

 zoid, in this case motionless and destitute of cilia, 

 is carried to the archegonium by water currents. 

 Among flowering plants spontaneous movement on 

 the part of the pollen - grain is of very doubtful 

 occurrence, though Dr. Horn asserts that the pollen- 

 grains of Cereus exhibit movements. Whether pollen- 

 grains ever actually move or not, w^e have a near ap- 

 proach to this in the movements of the pollen masses 

 of Orchis. It is noteworthy, also, that of the floral 

 organs the stamens are endowed with the power of 

 movement far more frequently than any other part 

 of the flower, e.g., Heliantheinum, Berberis, Parnassia, 

 etc. On the whole, however, distribution by the 

 vital activity of the corpuscle itself is mainly char- 

 acteristic of the male reproductive cells of the higher 

 CryptogaiTis. The frequency of spontaneous move- 

 ment in the male cell affords another illustration of 

 its superior adaptation for dispersion as compared 

 with the fertilised germ. 



Under this head may also be mentioned the 

 remarkable moving seed of Myzodendron, which, 

 without exaggeration, may be said to perform a 

 somersault on the branch of a tree. This plant 

 resembles the mistletoe in its parasitic habit; the 

 seed on alighting fastens itself to a branch of its 

 host by means of long tendril-like processes. In 

 several kindred parasites this fastening is effected 

 by the viscid exterior of the seed. Soon after this 

 the radicle emerges from the seed-coats, and curves 

 towards the branch, against which it presses with 

 its point. A flat disk is thus formed at the extremity 

 of the radicle, and this, as well as the seed, adheres 

 to the branch. If the spot happen to be unsuitable, 

 the radicle, instead of penetrating, straightens itself 



