263 TRANS. ST. LOUIS ACAD. SCIENCE. 



In Lahiates the awn-pointed lobes of the calyx are very effec- 

 tive, as in Lam'um, Melissa, Nepeta, PhlomU, etc. 



In Antirrhinum and Linuria the lips of the corolla come close 

 together, so that only such insects can get the nectar as are able 

 to push the upper lip back ; but the flowers are often perforated, 

 so that this is only a partial protection. 



In Symphytum officinale and other members of the Borrdginece 

 scales are developed which close over the throat of the corolla. 



In Passijiora the throat of the calyx is crowned with a double 

 or triple fringe of hairs. Quite as useful as this must be the inter- 

 mediate and plaited folds in the corollas of some Gentians, from 

 which teeth project into the opening of the flower. Viscid stems 

 and parts of the flower in close proximity to the essential organs 

 may also be of service. 



The glandular phyllodia of certain Acacias^ the involucral 

 bracts of Gossypium, the petioles of Cassia^ etc., secrete nectar, 

 by which ants and other insects are attracted directly to them, 

 and so do not molest the flowers. For an interesting discussion 

 of this subject I must refer to papers by Prof. Trelease,* Th. 

 Belt,| Kerner,J F. Delpino,§ O. Beccari,|| Ernst Huth,^ etc. etc. 



Pollen is protected in various ways. A curious case of protec- 

 tion is found in Ophrys insectift-ra, where the labellum simulates 

 the thorax of an insect which visits the flowers of some orchids. 

 As this plant is self-pollinated, the mimicry may be beneficial in 

 repelling insects. 



In Iris the stamens are sheltered under the over-arching petal- 

 like stigmas. 



The syngenesious stamens of Lobeliacece and Compositce open 

 inwardly around the style, so that there is not much waste of 

 pollen. The arched upper lip of labiate flowers, which is often 



* " Nectar and its Uses" in Comstock's Report on Cotton Insects, Dep'tof Ag'riculture, 

 Washington, D. C, 1S79; "Tlie Foliar Glands oi Pop it I lis,'" Bot. Gaz,, vol. vi. p. aSj, 18S1 . 



t " Naturalist in Nicaragua." London : 1874. p. 128 and 2ig. 



J "Die Schutzmittel der Bliithen gegen unberufene Gaste." Wien : 1S76. English 

 Translation by Dr. Ogle, " Flowers and their Unbidden Guests." London : 1S78. 



§ Atti R. University di Genova, iv. Pt. i. p. 26; " Funzione mirmecofila nel Regno Ve- 

 getale," In Memoria della R. Ace. delle Scienze dell. Jstit. di Bologna, p. 21. 



II " Piante ospitatrici ossia piante form Icarie della Malesia et della Papuasia"; "Male 

 sia;" vol. ii. fasc. t. ii. 18S4 ; fasc. iii. Florence. 



ir " Myrmocophile und myrmecophobe Pflanzen. Sammlung natuvwissenschaftlicher 

 Vortrage," herausgegeben von Dr. Ernst Hulh. Berlin : 1887. 



