Robertson — Floivers and Insects. 161 



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

 by humming birds. Am. Nat. 14:362. 1880.— (11) MUller, 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 Freilandpflanzeu. Jalirb. Bot. Gartens 

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

 BlUtenstiinde. Ber. Deut. bot. Gesellschaft 3: 409. 1885. A E. hippocasta- 

 num.— (15) Kirchner, Neue Beobachtungen liber die Bestilubungseinrichtun- 

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

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

 cimda.—(l&) Ascherson, Der Farbeuwechsel des Saft-raals in den Blliten der 

 Rosskastanie. Naturwiss. Wachenschrift 2: 129-30. 1888. (Just 161; 

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

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

 161: 531. Bot. Centralblatt 36: 264.) — (18) Beyer, Die spontanea Bewegun- 

 gen der Staubgefasse und Stempel. Wissenschaftliche Beilage zum Progr. 

 d. Kgl. Gymnasiums zu Wehlau, 54. 1888. AE. hippocastanum. (Just 161; 

 523)— (19) Focke, Der Farbenwechsel der Rosskastanien-Bluraen. Verb, 

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

 Ueber die gelben Fleckeu der Rosskastanienbliite. Sclir. Naturf . Gesellsch. 

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

 light. (Just 181: 463)— (21) Kirchner, BeitrJige zur Biologie der BlUthen. 

 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 19i: 420)— (23) 

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

 (Just 171; 531, 533-4. 18^: 485)— (24) Newell, The flowers of the horse- 

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

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

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

 Jlava, macrostachya. Ste 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 

 Carlinville, A. mexicanus belongs to the spring group of 



