1126 .JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



effects. This note contains an account of some experiments on the 

 maximum temperatures which seeds can withstand, and after which they 

 will retain their germinative power." The author gives a list of twenty- 

 two species, in ten natural orders, showing the highest temperature 

 under which the seeds survived and afterwards grew, the duration of 

 exposure being at least one hour. Medicago sativa survived the highest 

 temperature of all, viz. 121° C, but another leguminous plant, Trigonella 

 F(vnuvi-(jr<('cum, grew at the lowest temperature of all that survived, viz. 

 90° C. Seeds of Lagenaria vulgaris and Ileracleum gigantcum were un- 

 able to grow after exposure to that temperature. Convolvulus tricolor 

 comes next to Medicago sativa in power of resistance. " The seeds of 

 any one species show considerable individual differences in their power 

 of resisting high temperatures. . . . The time needed for germination is 

 increased by exposure to temperatures near the maximum. . . . Long 

 exposure to a comparatively low temperature may prove more fatal than 

 a short exposure to a high temperature. Thus, seeds which will germinate 

 successfully after one hour's exposure to 110°-120° C. (230°-248° F.) will 

 not germinate after twelve days' exposure to a temperature of 95°- 97° C. 

 r203°-206-6° F.)." — B. I. L. 



Anatomy of Selaginella. 



Selaginella, Contributions towards a Knowledge of the Ana- 

 tomy of the Genus. By R. J. Harvey-Gibson, M.A., F.L.S., Professor of 

 Botany in University College, Liverpool. Part IV. The Root (Ann. Bot. vol 

 xvi. No. 63, p. 449, with plates xx. and xxi.).— In this paper the root of 

 Selaginella is extensively treated, and is valuable for study and reference 

 on that account. It is most obviously interesting, perhaps, from the 

 views expressed by the author of the nature of the " rhizophore." 

 " Niigeli and Leitgeb's researches lay the foundation of our knowledge of 

 the anatomy of roots, and as their observations and conclusions have been 

 called in question by more recent investigators, it may be advisable to 

 summarise their results at somewhat greater length. Their observations 

 were apparently made on four species, viz. S. Kranssiana, S. Mertensii, 

 S. cuspidata, and S. laevigata. They commence by calling in question 

 the accuracy of applying the term 1 root ' to the organs arising at the 

 branchings of the stem, and point out that a root-cap is absent from the 

 apices of such organs. They further express their belief that these 

 bodies are in reality cauline in their homology, giving them the name of 

 ' rhizophores ' ( Wurzeltriiyer). Despite the fact that several authorities 

 have brought forward evidence and arguments against this view, the 

 name is still commonly employed in text-books, &c, to designate the 

 unbranched aerial portion of the root in such species as possess such 

 organs. In the present paper the 4 rhizophore ' is designated as the 

 1 aerial part of the root,' and that portion which is embedded in the soil 



the 'subterranean part.' " In addition to the absence of a root-cap, 

 Nageli and Leitgeb point out that the " rhizophore," as they term it, 

 is occasionally transformed into a leafy branch, and that it arises exo- 

 genousty, whilst the true roots are developed from it later endogenously. 

 This view is combated by Van Teighem and Russow, and the latter says 



