454 TRANS. ST. LOUIS ACAD. SCIENCE. 



Tliasfium aureum, Nutt. ; var. trifoliatum, C. & R. — Resembles Xxta^l, 

 Poljtienia, and Pimpinella. Plve umbels of each order bore an average 

 of flowers and umbellets as follows : 



ist order — 174 male and 37 hermaphrodite flowers in \i umbellets. 

 2d order — 98 " " 90 " " " 10 " 



3d order — 57 " '■ 98 " /' " 12 '• 



var. atropurpureum, C. \: R. 



Is^t order — 170 male and 13 hermaphrodite flowers in 11 umbellets. 

 2d order — 129 " '' 80 " " •' 12 " 



3d order — 94 " " 85 " " " 11 ' 



Umbels of the ist order are commonly male. The hermaphrodite 

 flowers are proterogvnous.* 



Pastinaca sativa, L. ("adv. from Eur.") — Schulzf has observed that 

 the primary umbels contain principally hermaphrodite flowers, while the 

 number of male flowers increases in umbels of the 3d order. The herma- 

 phrodite flowers are proterandrous, as is well known. 



The large umbels of yellow flowers are very attractive to insects. The 

 nectar is freely exposed. In comparing the lists it must be remembered 

 that this is the largest one, much more time having been given to it than 

 to any other plant. It shows the first Nyssonidas, and an increase in all 

 hymenoptera except Crabronidae, Andrenid?e, and Apidse. Although ob- 

 served nearly four times as much as Heracleum, it shows only 5 more flies. 

 Heracleum shows 20 more flies than hymenoptera, while Pastinaca shows 

 35 more hymenoptera than flies. 



In the P^ertilization of Flowers, 284, and Weitere Beobachtungen, i., 

 36, Miiller gives a list of 7 diptera and 8 hymenoptera. In the former 

 he says : " So the dull yellow flowers of this plant, like those of Buplurum 

 and Anethum, are visited by Diptera and Hymenoptera, not by Beetles." 

 Again, on p. 287, he says : "As a peculiarity which influences this assem- 

 blage of insects, I must mention the yellow color, for I have never found 

 the flowers of Buplurum, Silaus. or Pastinaca, visited by beetles." This 

 generalization was founded in the case of Buplurum falcatum on a list 01 

 only 8 visitors, and he afterwards, in the Weit. Beobachtungen. records 

 the occurrence of beetles on B. falcatum as well a*, on B. rotundifolium. 

 In a list of 46 species found in Anethum, no beetle occurs, but this may 

 be accidental. The list of visitors of Silaus is very fragmentary, -contain- 

 ing only 3 insects. In Bot. Gazette, vii., 24, Foerste mentions beetles as 

 visitors of Pastinaca, and on page 27 of the same Prof. Trelease refers to 

 Mlillei's statement. Finally. I have found Pastinaca to be visited by 40 

 species of beetles, which is nearly twice as many as Miiller ever found on 

 any plant of the order. 



* Foefste seems to have regarded some species of Thaspium( ?) as proterogynous. See 

 Bot. Gazette, vii., 71. f 1. c. 



