144 HARSHBERGER— STUDY OF THE CLOVERS. 



(8) ; West Tropical South America (i) ; Temperate South America 

 (12). 



Sleep Movements of Clover Leaves. 



Pf effer in his " Untersuchungen iiber die Entstehung der Schlaf- 

 bewegungen der Blattorgane," Leipzig, 1907, does not undertake to 

 investigate the clovers, although they provide more available material 

 than Alhizzia lophantha, Mimosa Spegazzini, Phaseolus, Lourea ves- 

 pertilionis, Mimosa pudica, Impatiens parviflora, and Siegesbeckia 

 orientalis investigated experimentally by him. 



The gross morphologic movements are of interest (Plates D, E). 

 The following species of clovers grown experimentally by the writer 

 move their terminal leaflets into a flat vertical position in their nycti- 

 tropic movements : Trifolium- alpestre, arvense, dubium, elegans, fili- 

 forme, glomeratum, incarnatum, maritimum, minus, pannonicum, 

 pratense (mammoth), pratense X pratense X medium, reflexum, 

 resupinatum, rub ens, spinosum. 



A few clover leaflets move so that the terminal leaflet is erect, 

 but folded somewhat inwardly along the midrib. Such are hybridum, 

 ochroleucum, pratense, pratense (old), and subterraneum. In these 

 two cases the lateral leaflets move upward and inward so that their 

 surfaces are applied together, the leaflets standing vertically as the 

 figures clearly show. The following species of Trifolium show the 

 terminal leaflets bent forward out of the vertical through an angle of 

 ' 10° to 30° from the vertical : alexandrinum, angustifolium, cernuum, 

 elegans, hybridum, incarnatum, johnstoni, leucanthum, medium, per- 

 reymondi, reclinatum, striatum, tridentatum. 



In Trifolium cernuum, elegans, medium., repens, perenne, the 

 terminal leaflets are folded along their midribs, so that their leaflets 

 overlap the two lateral leaflets which stand vertically and lie parallel. 



In T. montanum, repens (old), repens perenne, scabrum, the 

 terminal leaflets are nearly horizontal, forming almost an angle of 

 90° with the vertical. The positions of the leaflets in T. agrarium, 

 aureum, badium, bocconi, campestre, patens, procumbens, stcllatum 

 are different from the other species and are not suggestive of sleep 

 movements. Whether the nyctitropic positions assumed in these 

 clovers are due to experimentally unhealthy plants, future study of 



