660 ANGIOSPERMAE DICOTYLEDON ES 



structor Latz., at Vienna and Budapest. The ants keep off injurious insects. The 

 secretion ceases at the beginning of anthesis. 



1558. J. alata. According to Hildebrand ('U. d. Geschlechtsverhalt. b. d. 

 Compositen/ pp. 58-9), the style is similar in structure to that of Centaurea montana. 



Visitors. Loew observed the po-cltg. bee Osmia fulviventris Pz. $ in the 

 Berlin Botanic Garden. 



475. Alfredia Cass. 



1559. A. cernua Cass. 



Visitors. Loew observed the humble-bee Bombus terrester L. 5, po-cltg., in 

 the Berlin Botanic Garden. 



476. Rhaponticum Hall. 



1560. R. pulchrum Fisch. et Mey. (= Centaurea pulchra DC). 



Visitors. Loew observed 3 bees (1. Dasypoda hirtipes F. $, skg. ; 2. Osmia 

 fulviventris Pz. 5, po-cltg. ; 3. Stelis aterrima Pz. $, skg.) and a wasp (Odynerus 

 parietum Z.) in the Berlin Botanic Garden. 



477. Serratula Dill. 



Florets hermaphrodite or dioecious. 



1561. S. tinctoria L. (Kirchner, 'Flora v. Stuttgart,' p. 727; Herm. Miiller, 

 ' Fertilisation,' pp. 345-6 ; Knuth, ' Blutenbiol. Herbstbeob.') This species is gyno- 

 dioecious, and bears purple-red florets. Kirchner says there are transition-forms 

 between the female and hermaphrodite ones. 



Visitors. The following were recorded by the observers, and for the localities 

 stated. 



Herm. Mailer (Thuringia), a humble-bee (Bombus agrorum F. 5 and $, skg.) 

 and a butterfly (Colias hyale Z., freq., skg.). Knuth (Kiel Botanic Garden), 6 hover- 

 flies, po-dvg. and skg. (1. Eristalis horticola Deg. ; 2. E. pertinax Scop. ; 3. Platycheirus 

 sp. ; 4. Syritta pipiens Z. ; 5. Syrphus ribesii Z. ; 6. S. umbellatarum Z.), and 2 

 butterflies, skg. (Pieris sp., and Vanessa io Z.). Schiner (Austria), the Muscid 

 Trypeta ruficauda F. 



1562. S. quinquefolia Bieb. 



Visitors. Loew observed 2 humble-bees (Bombus agrorum F. t>, and B. terrester 

 Z. 5, skg.) in the Berlin Botanic Garden. 



1563. S. lycopifolia VOL, and 1564. S. centauroides Bieb. (=S. radiata 

 Bieb.). (Von Wettstein, 'Compos, d. 6st.-ungar. Flora.') Wettstein says that in 

 these species nectar is discharged in abundance from the stomata on the involucral 

 bracts of the young unopened heads, serving to attract ants that keep injurious insects 

 from the buds. {Cf. Jurinea mollis.) 



Visitors. Wettstein observed 4 ants on S. lycopifolia (1. Formica exsecta Nyl. ; 

 2. F. rufibarbis F. ; 3. Lasius niger Z. ; 4. Myrmica lobicornis Nyl.), and one (Lasius 

 alienus Forst.) on S. centauroides. 



