212 



OPENING OF THE PASSAGE TO THE INTERIOR OF THE FLOWER. 



be readily followed, and lasts barely two minutes. Still more rapid is the opening 

 of the Evening Primrose (CEnothera grandiflora). The petals spring apart quite 

 suddenly and stretch themselves out within half a minute. If ever the term 

 "bursting open" applies to a flower-bud, it does so here. In several tropical 

 Orchids, also, the parts separate quickly enough for the movements to be readily 

 visible. Thus, in the beautiful Stanhopea tigrina, the whole process only occupies 

 three minutes. It is worth mentioning, that during the opening of this flower, a 

 distinct noise is heard, not unlike the report caused by the bursting of the inflated 

 calyx of the Bladder-campion. 



There are flowers which open so early in the morning that they greet the first 

 rays of the rising sun with fully expanded corollas. That common garden climber, 

 Ipomcea purpurea, opens its buds at 4 a.m. Wild Roses, also, open between 4 and 

 5 a.m. Between 5 and 6 many species of Flax (Linum perenne and Austriacum) 

 open. Between 6 and 7, Willow-herbs (Epilobium angustifolium and collinum), 

 between 7 and 8, Convolvulus arvensis and tricolor. Between 8 and 9, many 

 Gentians, Speedwells, and Wood-sorrels, and the frequently-cultivated Himalayan 

 Cinquefoil (Potentilla atrosanguinea). Between 9 and 10 most Tulips and Opuntias 

 open; between 10 and 11, the Centaury (Erythrcea) and Chaffweed (Centunculus). 

 Between 11 and 12, Potentilla recta. From noon till evening comes a long interval. 

 No plant is known in our latitude which, under ordinary circumstances, opens 

 during the afternoon. Towards sunset, however, it recommences. About 6 p.m. 

 the Honeysuckle opens, shortly followed by the Evening Primrose and Campion. 

 Between 7 and 8 p.m. Hesperis matronalis and tristis, the Marvel of Peru (Mira- 

 bilis Jalapa), a few Catchflies (Silene noctiflora and vespertina) and several Thorn- 

 apples (Datura Stramonium). Between 8 and 9 more Catchflies (Silene longiflora, 

 Saxifraga, Vallesia), a Woodruff (Asperula glomerata), and a species of Tobacco 

 (Nicotiana affinis). Between 9 and 10, the Queen of the Night (Cereus nycticalus, 

 the Mexican cactus) opens. 



As it is with the commencement, so is it with the end of flowering; each happens 

 at a definite time, and every flower endures for a determinate period. Flowers 

 which are only open for a single day are termed ephemeral flowers. The annexed 

 table shows the hours of opening and closing of a series of ephemeral flowers. 





