Robertson — Flowers and Insects. 161 



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

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

 tion of Flowers, 161-6. 1S83. 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 Biologie der einseitswendigen 

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

 num. — (15) Kirchner, Neue Beobachtungen tiber die Bestaubungseinrichtun- 

 gen einheimischer Pflanzen. Progr. d. 68 Jahresfeier d. K. Wiirttemb. 

 landwirtsch. Akademie Hohenheim, 31. 1886. (Just 14 1 : 790). AE. rubi- 

 cunda. — (16) Ascherson, Der Farbeuwechsel des Saft-mals ia den Bliiten der 

 Rosskastanie. Naturwiss. Wachenschrift 2: 129-30. 1888. (Just 16 1 : 

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

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

 16 1 : 531. Bot. Ceutralblatt 36: 264.) — (18) Beyer, Die spontanen Bewegun- 

 gen der Staubgefasse und Stempel. Wissenschaftliche Beilage zum Progr. 

 d. Kgl. Gymnasiums zu Wehlau, 54. 1888. AE. hippocastanum. (Justie 1 : 

 523) — (19) Focke, Der Farbenwechsel der Rosskastanien-Blumen. Verh. 

 bot. Ver. Prov. Brandenburg 31: 108-12. 1889. (Just 18 1 : 473)— (20) Bail, 

 Ueber die gelben Flecken der Rosskastanienbliite. Schr. Naturf . Gesellsch. 

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

 light. (Just 18 1 : 463) — (21) Kirchner, Beitriige zur Biologie der Bliithen. 

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

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

 plants. V. Proc. Acad. Nat. Sci. Phila. 1890:274-6. (Just 19 1 : 420)— (23) 

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

 (Just 17 1 : 531, 533-4. 18 1 : 485)— (24) Newell, The flowers of the horse- 

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

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

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

 flava, macrostachya. See also (27) Jordan, Beitriige 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 

 Oarlinville, A. mexicanus belongs to the spring group of 



