Bobertson — Flowers and Insects. 169 



and Insects — Rosaceae and Compositae. Trans. Acad. Sci. St. Louis 

 6:437, 4-47-50, 477-9. 1894.— (23) Loew, Bliitenbiologische Floristik, 85, 

 224. 1894. Seven species. — (24) MacLeod, Bevruchting der bloemen van 

 Vlaanderen. Bot. Jaarboek 6:321-2, 380, 436-7. 1894.— (25) Knuth, 

 Weitere Beobachtungen iiber Blumen und Insekten auf den Nordfriesischen 

 Inseln, Schr. d. Nat. V. f. Schleswig-Holstein 10:233, 252. 1895.— (26 

 Willis and Burkill, Flowers and Insects in Great Britain. Ann. of Bot. 

 9:248. 1895. 



Gillenia stipulacea Nutt. — PoHeraiithus stipulatus 

 (Muhl. ) Brittou — The stems grow from 5 to 10 dm. high and 

 are terminated by a very loose cluster of white flowers which 

 expand from 20 to 25 mm. The stems are slightly inclined 

 so that the flowers are thrown into an almost horizontal posi- 

 tion, and there is a tendency on the part of the petals to 

 assume a position somewhat as in the violet, the three lower 

 ones extending more horizontally, and the two upper being 

 somewhat reflexed. 



The calyx-tube is quite long — 5 to 6 mm. — and narrow, 

 the stamens and pistils being included. When the flower 

 opens, the mouth of the tube appears quite narrow and is 

 filled with dehiscent anthers belonging to the outer stamens. 

 Later the innermost anthers discharge their pollen. After 

 the anthers have become empty, the calyx-tube opens wider at 

 the mouth, and the stigmas, which are now receptive, become 

 visible. 



The depth and narrowness of the tube render the flowers 

 most favorable for the smaller, long-tongued bees, though they 

 may also force their heads in for some distance. Insects 

 cannot reach the nectar without becoming thoroughly dusted 

 with pollen or touching the stigmas. The plant is rather 

 frequent in woods and blooms from June 3 to 29. On the 

 15th, 16th and 20th the following list was observed : — 



Bees — Apiclae: (1) Anthophora abrupta Say tf, s.; (2) Ceratina dupla 

 Say J 1 , s. & c. p., ab.; (3) C. tejonensis Cr. J 1 , s.; (4) Alcidamea producta 

 Cr. 9, s. & c. p., ab.; (5) Heriades carinatum Cr. J*9, s. & c. p., freq.; 

 (6) Osmia distincta Cr. 9, s. & c. p., ab. ; (7) O. albiventris Cr. ?, s. & c. 

 p.; (8) O atriventris Cr. $,s. ; (9) Nomada affabilis Cr. ?,s.; (10) Cal- 

 liopsis parvus Rob. tf$, s. & c. p., ab. ; (11) C. andreniformis Sm. tf. s.; 

 Andrenidae: (12) Halictus pectoralis Sm. tf%, s. & c. p.; (13) H. macoupi- 



