COMPOSITAE 599 



1402. I. thapsoides DC. 



Visitors. Loew observed the following in the Berlin Botanic Garden. 



A. Diptera. Syrphidae: 1. Eristalis arbustorum Z.; 2. E. nemorum Z. ; 

 3. Syrphus ribesii Z. B. Hemiptera. 4. Aelia acuminata Z. 



1403. I. viscosa Ait. (=Cupularia viscosa Godr. et Gren.). 



Visitors. Delpino observed Pieris, Vanessa, and other butterflies (' Ult. oss.,' 

 Atti soc. ital. sc. nat., xvi, 1873). 



1404. I. ensifolia L. 



Visitors. Schiner (Austria) observed the fly Myopites inulae v. Roser. 



1405. I. Conyza DC. (=Conyza squarrosa Z.). 



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

 stated. 



Schenck (Nassau), the leaf-cutting bee Megachile centuncularis Z. Schiner 

 (Austria), the fly Tephritis zelleri Loew. Schletterer and von Dalla Torre (Tyrol), 

 the bee Halictus sexcinctus F. 



434. Pulicaria Gaertn. 



Ray- florets uniseriate, female; disk-florets tubular, hermaphrodite. Stylar 

 branches beset with stigmatic papillae over their entire inner surfaces; the upper 

 third of their outer surface covered with sweeping-hairs directed obliquely upwards. 



1406. P. dysenterica Gaertn. (= Inula dysenterica Z.). (Herm. Muller, 

 'Fertilisation,' pp. 324-6, ' Weit. Beob./ Ill, p. 90; Giard, Bot. Jaarb. Dodonaea, 

 Ghent, ii, 1890, pp. 334-7; Knuth, ' Bloemenbiol. Bijdragen.') This species is 

 gynomonoecious. Upwards of 600 yellow disk-florets are surrounded by about 100 

 ray-florets of the same colour. Hermann Muller states that the corolla-tube is about 

 4 mm. long. Only the stylar branches (about \ mm. in length) project from the 

 anther-cylinder. These branches spread out horizontally and become recurved, 

 so that the stigmas occupy the place where pollen was to be found in the first (male) 

 stage. Hence insect visitors creeping about on the head pollinate simultaneously 

 numerous florets in the female stage. The triangular valves forming the upper 

 ends of the anthers are fringed with hairs, which are much longer and thicker than 

 the sweeping-hairs : they hold the pollen pressed out of the anther-cylinder. 



At Boulogne (Pas-de-Calais) Giard (1877) found several plants bearing abnormal 

 heads, some female and devoid of a ray, others male with an imperfect one. The 

 florets contained either vestigial stamens or vestigial pistils, and were degenerate in 

 other respects. For ten years in succession Giard removed all the normal stocks 

 from this station, and so converted the originally gynomonoecious plant into a purely 

 dioecious one. 



Visitors. I only saw the butterfly Vanessa urticae Z., skg. 



Herm. Muller observed the following. 



A. Coleoptera. Chrysomelidae : 1. Cassida murraea Z., not infrequent, creeping 

 over the heads. B. Diptera. Syrphidae : 2. Eristalis arbustorum Z., very common, 

 po-dvg. ; 3. E. sepulcralis Z., do. ; 4. Melithreptus scriptus Z., po-dvg. ; 5. Syritta 



