Francis E. Lloyd — 182 — Carnivorous Plants 



In young plants derived from leaf cuttings (seen growing in Mu- 

 nich) the lobes of the traps were usually quite oblique in form, and 

 the cilia were very irregular and often very small. Both kinds of 

 glands were present in small numbers. I counted six alluring glands 

 clustered near each of the outer angles of the lobe in one, and three 

 in another trap. The digestive glands were more numerous, but still 

 few and scattered. The sensitive hairs were absent in one case, and 

 from one to two occurred in several others. While small, they showed 

 all the normal histological details. 



During development the blade and trap both display circination. 

 In the latter the two lobes are rolled inwardly and gradually un- 

 fold, the cilia being the last to unroll. The blade lobes are inrolled 

 longitudinally at first, but as it develops the axis of the roll grad- 

 ually comes to lie more transversely, the last portion of the blade 

 to unroll being the apex. At first also the trap is bent sharply back 

 on the blade, but lying asymmetrically on its right lobe, which presses 

 against the blade surface. With further growth the trap swings 

 forward on its stalk, and now comes to lie more or less on its left 

 lobe, or otherwise expressed, the trap is twisted more or less to the 

 left (as seen from above) (iS — 7). This posture is more evident 

 in small plants, with small traps, than in plants large enough to 

 produce normal sized traps. It is, however, often quite evident in 

 the latter, as I have myself observed in plants growing under my 

 eye. In the account beyond of Aldrovanda, it will be seen that in 

 this plant the trap always lies on its left side, a position which offers 

 distinct advantages in the trapping of prey. Much less marked, how- 

 ever, is the posture just mentioned for Dionaea, and it cannot be 

 said to be of any significance. I have never seen the trap bending 

 to the right (as seen from above). 



Structure of the mature leaf. — The structure of the leaf has often 

 been the subject of examination (Oudemans, 1859; Daewin, 1875; 

 Kurtz, 1876; de Candolle, 1876; Fraustadt, 1877; Goebel, 1891; 

 Haberlandt, 1901; GuTTENBERG, 1925). The winged form of the 

 petiolar region traversed by a single vascular bundle, which presents 

 nothing further of special interest, is regarded by Goebel as a physio- 

 logical compensation in the interest of photosynthesis, such compen- 

 sations being generally found among the carnivorous plants. In 

 seedlings the petiole is relatively much larger. 



The outer part of the leaf, the blade, is the trap. This consists 

 of two lobes, trapezoidal in form, united along the middle line by a 

 thick midrib, which has often been considered a hinge, but which 

 has no hinge function {i8 — i). At their bases the lobes have their 

 greatest thickness, thinning off gradually as the margins are approached 

 {18 — 4b). Here, however, they are thickened locally by the enlarged 

 bases of the marginal cilia. These are prominent, tapering, finger-like 

 processes, evidently emergencies (Solereder), which are so placed 

 that when the lobes are approximated they interweave like the fingers 

 of closed hands. The cilia have been thought to be homologous with 

 the tentacles of Drosera, but, as Goebel pointed out, the comparison 

 fails in that the ciha show no trace of glandular tissue, and have 

 evidently a widely different function. The whole trap acts, to quote 



