Pinguicula. 5 5 



pass to gain access to the flower. Thus we find these 

 substances on the radical leaves, on the stipules, on the 

 bracts, on the perianth leaves, on the andrcecium, and, 

 exceptionally, even on the gynaecium. 



The genus Pinguicula is worthy of prominent notice 

 here, for it is, with certain Primulaceae {Primula 

 glutinosa Wulf., Primula villosa Jacq., Primula hirsuta 

 All, Primula viscosa, P. tiroliensis Schott), one of the 

 most instructive examples of those cases in which creep- 

 ing insects are prevented from gaining access to the 

 flower by viscid radical leaves, spread out in a rosette on 

 the ground. The structure of these flowers reminds one 

 very much of the Bromeliaceee, already described, 

 (Vriesia psittacina, etc.), where the rosette of leaves 

 forms a basin out of the middle of which rises a slender 

 flower stem. But whereas in these latter plants the 

 basin is filled with rain and dew, in Pinguicula alpina 

 L., P. leptoceras Echb., P grandiflora Lam., P. vul- 

 garis L., etc., the upper surface of the leaves which 

 form the radical rosette is coated over with a tenacious 

 viscid slime. This sticky matter is secreted by small 

 glandular trichomes that are so thickly crowded together 

 on the upper surface of the leaves that (in P. alpina 

 L.) I could count nearly a hundred of them on a square 

 mm. (Plate I. Fig. 3, section of a leaf). These glan- 

 dular trichomes are of two kinds. Either they are 

 wart-shaped epiblastemes of the epidermis which are 

 divided into from eight to twelve chambers or cells 



