CRUCIFERAE 



"5 



All of them dehisce introrsely, and remain in their original position ; those of the 

 long stamens project a little from the entrance of the flower, while those of the short 

 stamens together with the stigma are in it. Automatic self-pollination is possible, 

 though the anthers are remote from the stigma. 



285. T. praecox Wulf. 



Visitors. Schletterer observed the following at Pola. 



Hymenoptera. (a) Aptdae: 1. Andrena convexiuscula K. ; 2. A. deceptoria 

 Schmiedekn. ; 3. A. tscheki Mor. {5) Tenthredinidae : 4. Athalia rosae Z., var. liberta 

 King. 



85. Teesdalia R. Br. 



Small, white, bilaterally symmetrical flowers, with half-concealed nectar. Four 

 nectaries. 



286. T. nudicaulis R. Br. (Herm. Miiller, 'Fertilisation,' pp. 106-8, ' Weit. 

 Beob.,' II, pp. 199-200 ; Knuth, ' Bl. u. Insekt. a. d. nordfr. Ins./ p. 20, Weit. Beob. 

 EL Bl. u. Insekt a. d. nordfr. Ins.,' p. 231.) Hermann Miiller says that during 

 anthesis the flowers are aggregated to form a flat surface, and the outer petals are 

 larger than the others, as in the Umbelliferae. In Teesdalia, however, as the flowers 

 successively fade the axis of the inflorescence lengthens, and the flat surface is drawn 

 out into a raceme, each flower becoming marginal in its turn. Hence all the flowers 

 have the outer side of the corolla enlarged, and not only as in the Umbelliferae and 

 Compositae those which are originally at the edge. 



Fig. 34. Teesdalia nudicaulis, R. Br. (after Herm. Miiller). (i) Flower seen from above, (a) An- 

 terior half of a flower. (3) One of the long stamens with a nectary, seen from outside. (4) One of the 

 two short stamens, seen from outside, s, inner sepal ; *", outer sepal ; s*, lateral sepal ; />, inner petal ; 

 P 1 , outer petal; a, short stamens; a 1 , inner long stamens; a 2 , outer long stamens; x, y, petaloid 

 appendages of the filaments ; w, nectary ; ov, ovary. 



The white-tipped sepals enhance conspicuousness, but this is chiefly attained 

 by the white petals, supplemented by petaloid appendages of the filaments. The 

 appendages of the four inner stamens closely surround the compressed ovary. Each 

 of these possesses a small pouch immediately above the middle of the base of the 

 adjacent petal, which is also pouched. Between the two, is a small green fleshy 

 nectary, which is functional, and appears to belong to the torus. 



The anthers of the four long stamens project somewhat beyond the stigma, while 

 those of the two short ones are at the same level. All six make a quarter-turn when 

 the flower opens ; each long one turning towards the adjacent short one, while each 

 of these is directed towards the outside of the inflorescence. The anthers now 

 dehisce, and the stigma simultaneously matures. Insects probing towards either 



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