COLOURS OF FLOWERS AS A MEANS OF ATTRACTING ANIMALS. 185 



furnish a means of allurement, as is the case in Eryngium, amelhystinum, cretictim, 

 &c., as well as other plants. 



When a coloured object is less than a certain size not even the most vivid red, 

 the brightest yellow, or most dazzling white will render it visible at a distance. If 

 the parts of the flower or the envelopes whose function is to attract flying animals 

 from a distance are to be serviceable as signs, they must occupy a considerable 

 space, a necessity pi-ovided for in various ways, one of which is the large size of 

 the individual flower. But it would be an error to suppose that this method, from 

 its apparent simplicity, is the most frequent; in point of fact it seldom occurs. 

 Scarcely one in a thousand of the flowers of Phanerogams exceeds 10 centimetres 

 in diameter, and most of these are found only in ti'opical countries. A species of 

 Rafflesia, which has the largest flowers in the world, is illustrated in vol. i. p. 203. 

 The Rafflesia Schadenbergiana, which flourishes in the Island of Mindanao in the 

 Philippines at a height of 800 metres above the sea, parasitic on the roots of Cissus 

 plants, develops flowers weighing about 11 kilogi-ams a-piece, with a diameter of 

 about 80 centimetres. To be mentioned with these Rafilesias, in respect of extreme 

 diameter, are the flowers of the rare Peruvian orchid, Paphiopediliwm (Gypri- 

 pedium) caudatum, whose ribbon-like lateral petals attain a length of 70 cm. 

 These tailed lateral petals hang down moustache-like right and left of the flower, 

 and though when the flower first expands they are only some 10 cm. long, they con- 

 tinue growing for about ten days, in which time they usually attain their full length. 

 From the second to the seventh day they have been observed to increase in length 

 as much as 5 cm. each day. Very large also are the balloon-like flowers of several 

 tropical American Aristolochias, of which it is stated that children use them in 

 play as caps and pull them down over their heads. Thus the flowers of the Guate- 

 malan Aristolochia gigas, var. Stiirtevantii (cultivated in the Botanic Gardens at 

 Kew) are about 45 cm. wide, 55 cm. long, with a tail exceeding a metre in length; 

 their colour is creamy yellow and deep maroon purple. But of course the amount 

 of substance composing these tailed and inflated flowers is as nothing compared 

 with that which goes to make a huge Rafflesia-&ower. The flowers of Magnolia 

 Camphellii belonging to Sikkim (Himalaya) display almost as great a diameter 

 as those of these tropical creepers. When the erect red flowers of this tree open 

 in the sunshine they show a width of 26 cm., a size never attained by any other 

 tree-flower. One of the Lotus plants, viz. Nelumho speciosum, as well as the 

 Australian Nymphoia gigantea, produces flowers with a diameter of 25 cm.; the 

 Lilitim auratum, recently much planted in European gardens, flowers of 24 em. 

 Many Cactuses exhibit flowers with a diameter of 20-22 cm., viz., Echinopsis 

 cristata, Cereus grandijiorus, the Queen of the Night (Cereus nycticalus), shown 

 in Plate VII. (vol. i. p. 641), the South American Datura Knightii, Kywphcea 

 Bevoniensis, and the celebrated Victoria regia, represented in the accompanying 

 Plate XI., "Victoria regia in the River Amazon". Nelumho luteurn, Amaryllis 

 solandr [flora, and the Opium Poppy (Papaver somniferum) have flowers of 16-18 

 cm. diameter, Amaryllis aulica and equestris, Datura ceratocaula and Pceonia 



