214 



THE FLOWERING PROCESS 



JO 36. Long-day plants promoted by low temperature. 



\o 



Avena sativa, H. 36, C. 197 

 Bromus inermis, H. 29 

 Dianthus arenarius, C. 213, 218 

 Dianthus gallicus, C. 212, 218 

 Hordeum vulgare, H. 24, C. 197 

 LoUiim italicum, H. 42 

 Oenothera siiaveolens, C. 203, 218 



„ longi flora 



„ striata 

 Spinacia oleracea, C. 201 

 Triticum aestivum, H. 52, C. 197 



Oat 



Bromegrass 

 Carnation 

 Carnation 

 Winter barley 

 Italian ryegrass 

 Evening primrose 



Spinach, variety 3 

 Winter wheat, most 

 varieties 



1(T 



37. Long-day plants promoted by high temperatm-e. 



Phlox paniculata, H. 95 Phlox 



1 O 38. Long-day plants with a low temperature requirement. 



Anagallis tenella, C. 214, 218 

 Beta vulgaris, H. 55, C. 199 

 Cichorium intybus ? C. 204 

 Crepis biennis ? C. 205 

 Dianthus coesius, C. 213, 218 

 Dianthus graniticus, C. 213, 218 

 Lolium perenne, H. 43, C. 211 

 Lolium perenne, H. 44, C. 211 

 Lysimachia nemorum, C. 214 

 Oenethera lamarckiana, C. 202, 



218 



Oenothera parviflora biennis, C. 222, 218, 



202 

 Oenothera strigosa biennis, C. 202, 236, 



218 

 Saxifraga hy no ides, C. 214 

 Spinacia oleracea, H. 17 



Pimpernel 



Sugar beet 



Chicory, variety 



Hawksbeard 



Carnation 



Carnation 



Early perennial ryegrass 



Late perennial ryegrass 



Loosestrife 



Evening primrose from 



forests of Fontainebleau 



Evening primrose 



Evening primrose 



Spinach, variety 1 



39. Long-day plants; low temperature required; critical dark period is 

 inversely proportional. This variety of Hyoscyamus is also a classic in 

 research on photoperiodism and vernalization. 



Hyoscyamus niger, H. 110, C. 192, 197 Henbane, biennial strain 

 218 



40. Quantitative short-long-day plant; short-day effect replaced by low 

 temperature; no direct temperature effect. This includes the classic winter 

 rye, studied so extensively over a period of many years. According to 

 early studies, this plant would have been classified only as a quantitative 

 long-day plant, promoted by low-temperature (category No. 1 5). Detailed 

 studies, however, warrant placing of the plant in this complex category, 

 and the possibihty is immediately raised that many other plants might 

 find themselves in such complex categories if study of them were carried 

 out to a sufficient degree of detail. 



Secale cereale, H. 41, C. 194 Winter rye 



Iberis durandii, C. 223 Candytuft 



