Bobertson — Flowers and Insects. 161 



30. 1878. AE. hippocastanum. — (10) Trelease, Fertilization of flowers 

 by hamming birds. Am. Nat. 14:362. 1880.— (11) Miiller, Fertilza- 

 tion of Flowers, 164-6, 1883. AE. hippocastanum, rubicunda. — (12) Coul- 

 ter, Notes on Aesculus glabra. Bot. Gaz. 8:245. 1883. — (13) Loew, 

 Blumenbesuch von Insekten an Freilandpflanzen. Jahrb. Bot. Gartens 

 Berlin 3: 84 (16). 1884.— (14) Urban, Zur Biologic der einseitswendigen 

 Bliitenstande. Ber. Deut. bot. Gesellschaft 3: 409. 1885. AE. hippocasta- 

 num. — (15) Kircliner, Neue Beobaclitungen iiber die Bestaubungseinrichtun- 

 gen einlieiraischer Pflanzen. Progr. d. 68 Jaliresfeier d. K. Wiirttemb. 

 landwirtsch. Akademie Hohenheira, 31. 1886. (Just 14^: 790). AE. rubi- 

 cunda. — (16) Ascherson, Der Farbenwechsel des Saft-raals in den Bliiten der 

 Rosskastanie. Naturwiss. Wachenschrift 2: 129-30. 1888. (Just 16i: 

 548) — (17) Martelli, Dimorflsmo florale di alcune specie di Aesculus. Nuov. 

 giorn. bot. Ital. 20: 401-4. 1888. AE. hippocastanum, carnea, flava. (Just 

 161; 531. Bot. Centralblatt 86: 264.)— (18) Beyer, Die spontanea Bewegun- 

 gen der StaubgefSsse und Sterapel. Wissenschaftliche Beilage zum Progr. 

 d. Egl. Gymnasiums zu Wehlau, 54. 1888. AE. hippocastanum. (Justl6i: 

 623) — (19) Focke, Der Farbenwechsel der Rosskastanien-BIuraen. Verh. 

 bot. Ver. Prov. Brandenburg 31: 108-12. 1889. (Just 18^: 473)— (20) Bail, 

 Ueber diegelben Flecken der Rosskastanienblute. Schr. Naturf. Gesellsch. 

 Danzig 7: 6. 1890. AE. hippocastanum, carnea, color changes and sun 

 light. (Ju3t 181: 463)— (21) Kirchner, Beitrage zur Biologic der Bliithen. 

 Progr. z. 72 Jahresfeier d. K. Wiirttemb. landwirtsch. Akademie Hohen- 

 heim, 30. 1890.— (22) Mcehan, Contributions to the life histories of 

 plants. V. Proc. Acad. Nat. Sci. Phila. 1890:274-6. (Just 19^: 420)— (23) 

 Kerner, Pflanzenleben 2: 179 etc. 1891. AE. hippocastanum, macrostachya. 

 (Just 17^: 531, 533-4. 181? 485)— (24) Newell, The flowers of the horse- 

 chestnut. Bot. Gaz. 18: 107. 1893.— (25) Knuth, Blumen und Insekten auf 

 den Nordfriesischen Inscln, 50. 1894. AE. hippocastanum. — (26) Loew> 

 Bliitenbiologische Floristik, 208-9. 1894. AE. hippocastanum, rubicunda, 

 Jlava, macrostachya. See also (27) Jordan, Beitrage z. physiol. Oranogra- 

 phie d. Blumen. Ber. d. D. Bot. Ges. 5: 338-40. 1887. AE. hippocastanum. 



Astragalus L. — The observations made upon this genus 

 indicate an adaptation of the flowers to bumble-bees, though 

 some species are also visited by other bees, such as Megachile. 

 A. alpinus (6) shows a tendency to change to a butterfly- 

 flower. In those cases in which the stigma surpasses the 

 anthers, cross-pollination is indicated, while those in 

 which these parts are near together have been supposed to 

 be spontaneously self-pollinated. It seems, however, in these 

 cases that it needs to be shown that the stigma is capable of 

 being properly pollinated before it has been rubbed 

 (Heinsius 19). 



Of the two species which are the only ones found about 

 Carlinville, A. mexicanus belongs to the spring group of 



