FOR ARTIFICIAL REPRODUCTION. 551 



of October, or the beginning of Xovember ; exceptionally, and 

 especially in damp weather, they may remain unopened on the 

 trees and fall during dry east winds in December and January, 

 frequently on to the snow. Horiil)eain-nuts ripen in October, 

 but usually remain hanging on the trees till the end of winter, 

 especially on large trees in damp localities. Birch-Catkins often 

 ripen in June, but in July and August when the weather is 

 unfavourable ; their dissemination is also irregular, being at the 

 end of July when the catkins ripen early and the weather is 

 favourable, otherwise, during autumn ; not unfrequently they are 

 still hanging on the trees in November. If the catkins come to 

 pieces when handled it is a sign that the seed is ripe. Few 

 trees produce more sterile seed than the birch, and birch-seed 

 may be considered good if 30 — 40% of it will germinate. 

 Alder-Catkins ripen at the end of September or early in October ; 

 the seed rarely falls before the end of November, but usually the 

 closed catkins remain hanging on the trees through the winter, 

 and open and shed the seeds only in February and March. The 

 middle catkin scales open first and contain the best seed. Elm 

 samaras ripen by the end of May or the beginning of June, and 

 are disseminated very soon after ripening. 



[Seeds of the wych-elm should be kept separate from those of 

 the common elm. They are readily distinguished from one another 

 by the seed being in the middle of the samara of the mountain or 

 wych-elm. — Tr.] 



Elm-seed ripens irregularly, green samaras being on the trees 

 after much seed has fallen. Only the samaras which ripen late 

 are fertile, those falling early being all sterile. From 30 to 

 50 % of elm-seed is bad. Ash-samaras ripen in October, and 

 usually hang on the trees through the winter, falling during dry 

 weather in February and March. The fruit of the mountain-ash 

 (Pyrus Aucuparia) ripens in September, and frequently remains 

 for a long time on the trees. Samaras of the sycamore and 

 other indigenous maples usually ripen in September and October, 

 falling a few weeks after maturity ; occasionally, especially in the 

 case of sycamore, the fruits remain hanging on the trees in 

 winter and fall on the snow. Lime ripens its fruit at the end of 

 October, the latter falling with the peduncles attached to it late 

 in the autumn and during winter. Much lime-seed lying on 



