NOTES 717 



51. Damm : Beih. hot, Centr. 11, 1902. Emma Ott : Ost. bot. Zeitschr. 1900. 



52. Stahl : Jena. Zeitschr. 12, 1888 (plants and snails). Kohl: I.e. [20]. 



53. Calcium oxalate in epidermal voaUs. Solms-Laubach : B.Z. 1871. Heimerl : 

 Sitzb. Wien, 93, 1886. 



54. Varnished leaves. G. Haberlandt : I.e. [28], pp. 105 sqq. Wiesner : Festchr. 



zool.-bot. Ges. Wien. 187(5. 



y>r>. G. Haberlandt : Ann. Buit. 11, 1893, p. 114 (wettable velvety epidermis). 



56. Persistent epidermis. Damm's (I.e. [51 ] ) results do not agree in all particulars 

 with those of the author. At the end of the first year, according to Dam m, the 

 outer epidermal wall is thrown into folds over the radial septa, but only rarely develops 

 any fissures. Careful re-examination, however, only confirms the author in his 

 previous conclusion, to the effect that cracks are formed and not folds. The only 

 possible explanation seems to be, that Damm and the author have examined different 

 plants. Damm identifies his material as " Acer pennsylvanicum (striatum)." The 

 author's own material was taken from specimens in the botanical gardens at Graz, 

 labelled " Acer striatum, Lam., X. America." The Graz identification is undoubtedly 

 correct. Possibly Damm's plant was really Acer striatum, hort. ( = A. palmatum, 

 Thunb.). Cf. Pax : Aceraceae (in Engler's Pflanzenreich). 



57. Burns : Flora, 1900. 



58. Von Hohnel : Wissensch.-prakt. TJnters. 1, 1875, pp. 149 and 162. 



59. Mucilaginous inner icalls. Radlkofer : Monographie d. Gattung Serjania, 

 1875, p. 100. 



60. Chloroplasts in the epidermis. Stohr : Sitzb. Wien, 79, 1879. 



61. Water-storing function of epidermis. Westermaier : P.J. 14, 1883, pp. 43 sqq. 



62. Vesicular (water-storing) epidermal cells- Volkens : Flora, d. agyptisch- 

 arabischen Wuste, Berlin, 1887, pp. 52 sqq. 



63. Water-storing capacity of the ordinary epidermis. The material used in these 

 experiments consisted of leaves of Horse-chestnut, Hazel and Pear, for all of which 

 the daily rate of transpiration had already been calculated (G. Haberlandt : Sitzb, 

 Wien, 101, 1892). The radial diameter of the two epidermal layers combined, amounl s 

 to -025 mm. for Aesculus, -02 mm. for Corylus and -0325 mm. for Pyrus. The 

 volume per sq. dcm. of both epidermal layers together, therefore, works out as 

 follows : 



Aesculus -25 cc. 



Corylus - - - - - - -2 ,, 



Pyrus ------ -325 ,, 



Assuming that the epidermis gives up one-half of its total water contenl to (lie trans- 

 piring mesophyll, when the external water-supply is cut off and transpiration goo 

 on at the ordinary rate, the quantities of water available per sq. dcm. are as follows : 



Aesculus -125 g. 



Corylus - -1 



Pyrus .... - 162 



