3/6 GENERAL REVIEW. 



flowers expand (see ' Garden,' iii. 499., for a highly-interesting 

 illustrated account of the way in which Yuccas are fertilised by 

 Pronuba yuccasella, Riley). More recent observations show 

 that the Yucca moth does not insert her eggs into the stig- 

 matic cavity, as was originally supposed, but that she lays 

 them in the side of the young ovary by puncturing it with 

 her ovipositor, after which she carries pollen and fertilises the 

 stigma. 



Yuccas do occasionally, although rarely, produce seed in 

 this country, and apparently without insect agency, although it 

 is next to impossible to be certain on the latter point. The 

 late Dr Englemann of St Louis, writing in 1872 (see ' Gard. 

 Chron.,' 1872, p. 941), says that it is impossible for the heavy, 

 sticky pollen to reach the stigma without some extraneous aid ; 

 and adds that he has succeeded in fertilising the flowers just 

 after they open in the evening. 



Yucca quadricolor variegata has fruited in the gardens of 

 La Muette. This plant is a variety of Y. aloifolia, of which it 

 presents the general appearance and habit. The leaves, how- 

 ever, have a broad whitish-yellow band running through the 

 centre. The fruit is also curiously marked, like the leaves, 

 with a broad whitish - yellow band. M. Carriere considers 

 that a large proportion of the seeds will reproduce the vari- 

 egation. 



The seeds of Yuccas germinate in a very curious manner. 

 Instead of throwing up the plumule from the apex of the seed, 

 and pushing the roots downwards, as in most Dicotyledons, 

 Yucca seeds, in common with those of Palms, Clivias, and 

 many other Monocotyledonous plants, throw out a long, 

 curved, neck-like growth (tigdlum), the swollen end of which 

 contains the embryo ; and after the neck has attained the 

 length of about an inch, more or less, the embryo throws up 

 a leaf and pushes down root - fibres nearly simultaneously. 

 Cyclamen seeds germinate in much the same way, and this is 

 the only instance of a Dicotyledon germinating in this curious 

 manner that I can just now remember to have seen. With 

 respect to seeds of this description, the question naturally 

 arises, Why is the embryo thrown out of the seed before ger- 

 mination has taken place ? Naturally, as we know, seeds are 

 scattered on the surface of the soil; and this is undoubtedly 

 one of Nature's ways of burying the embryo, and, until it 

 forms roots and leaves, it is nourished by the feeding-bottle- 

 shaped mass of cellular matter which remains on the surface 

 of the soil. We have instances of plants which bury, or 

 attempt to bury, their seeds, such as Trifolium subterraneum , 



