209 



Stomata of Trillium Nivale. 



F. M. Andrews. 



Gurabel 1 was the first to make known the presence of twin stomata. 

 Since that time Pfitzer 2 and others have shown the presence of stomata in 

 groups of two or more on the leaves of various plants. In Saxifraga sar~ 

 mentosa stomata are aranrged "in circular groups" 3 in considerable num- 

 ber. In various species of Begonias, as De Bary states 4 in Begonia mani- 

 cata, B. spathulata, B. Dregei and B. heraeleifolia two or more stomata 

 are arranged over one respiratory cavity. 



This occasional grouping of the stomata in certain plants is even more 

 strikingly shown in Trillium nivale. The stomata are often found on the 

 leaves in pairs over a common respiratory cavity, but frequently in num- 

 bers up to ten or more. In opening and closing they act just as a single 

 stoma does. 



The presence of more than one stoma over a common respiratory 

 cavity is also shown on the sepals and petals. Figure 1 shows part of a 

 sepal of Trillium nivale in which the stomata are in pairs in one case and 

 in threes in another case over a common respiratory cavity. These arise 

 from the successive division of a common mother cell. The stomata on 

 the sepals and petals are frequently lateral or diagonal as regards one 

 another, but in every case their origin from one mother cell is the same. 

 The arrangement in groups of as many as ten or more over one respiratory 

 cavity on the sepals or petals is also met with. 



Figure 2 shows a case, taken from the outside of a sepal, where only 

 one guard cell, A, is fully formed. There is only a remnant of a second 

 guard cell, B. The same thing has also been observed on the inside of the 

 petal. 



•Giimbel. Jahr. fur wiss. Bot. Bel. 7, p. 551. 

 'Pfitzer, E. Jahr fur wiss. Bot. Bd. 7, pp. 532-560. 



'Treviranus. Verm. Schriften, IV. 30. Quoted from DeBary, A. Comparative Anatomy of 

 Phanerogams and Ferns. 1884 p. 47. 



••Vivani. Quoted from DeBary as above. 



14— 49G6 



