238 ANGIOSPERMAE—DICOTYLEDONES 



the pollen is shed, and lastly the occurrence of a mass of germinating pollen-grains 

 on the upper surface of the closed stigma. All these facts, in Loew's opinion, lead 

 to the conclusion that the cleft between the anterior stamens is a ' pollinating 

 chamber,' while the ligular tips are ' pseudo-stigmas, or pollen-catchers.' When, 

 for example, a humble-bee of suitable size — Bombus agrorum F., and B. terrester 

 Z., on the Peacock Island at Potsdam^flies to the wide opening of the flower, 

 it first alights on the under-lip, the lateral teeth serving as points by which to hold on. 

 It then tries to thrust its head under the sexual apparatus that hangs down from 

 the roof of the flower-entrance, so as to penetrate into the wide sac-like sepal that 

 secretes nectar at its end. When pressing its head against the androecium, it 

 probably pushes forward a little the end of the contained stigma, which is directed 

 obliquely to the front, and with the stigma it moves the pollen-catchers (i. e. the ligules). 

 But even without this assumption, a humble-bee must in many cases, when pressing 

 against the anterior margin of the androecium, introduce its prominent cephalic 

 hairs into the cleft, so as to come into contact with the top of the pistil. When 

 in this way a bee brings pollen from a flower previously visited, this pollen will 

 be retained by the funnel-shaped ligular cap, and will germinate on the stigmatic 

 surface at the top of the ovary. The fact that the stigma of I. Roylei remains 

 closed, the ligular cap obviously occupying its place, lends special probability to 

 this interpretation. 



Loew also observed a dwarf-flower, intermediate in character between chasmo- 

 gamous and cleistogamous blossoms. Actual cleistogamous flowers, such as have 



Fig. 73. Im^atieiis glanduligera, Lindl. (Longitudinal section- From nature ) A. Flower in the 

 first (male) condition: the pollen-covered anthers (a) are above the entrance to tlie tlouer. li. Flower 

 in the second (female) condition: the stigma is) is above the entrance to the llower. 7z, nectary. 

 (Natural size.) 



been described for numerous species of this genus, have not hitherto been noticed 

 in I. Roylei. 



Visi'iORS. — In the Kiel Botanic Garden I observed the following 3 humble-bees, 

 all very freq., skg. — i. Bombus agrorum F. 5 and 5; 2. B. lapidarius L. S; 3. B. 

 terrester L. 5 and J. I also noticed Apis mellifica I,. 5, which readily touches the 

 anthers or stigma with its dorsal surface when entering or leaving the flower. 

 It can therefore eflfect cross-pollination. 



603. I. latifolia L. — According to Loew (op. cit), this species bears lepido- 

 pterid flowers, possessing stigmas that are not covered, but project in the form 

 of thin, feebly lobed membranous lamellae. 



