612 



HORTICULTURE 



May 12, 19oC 



give mainly normal plants with occasional altered ones 

 and it is only, as aforesaid, that by selection and after 

 a few generations that constant plants can be obtained 

 and among these, even, will be found a few better ones 

 and some that are worthless. Greenhouse ferns have not 

 been worked much in that direction but in the hardy 

 section great results have been secured. 



Abnormality or monstrosity in ferns is a change in 

 the form of the tissue in the nervations of the frond : 

 iu normal plants and in the first case the nervations 

 which feed the soris are all alike throughout the entire 

 length of the frond and when not sterile are not liable 

 to change much by spore seeding. In some plumose 

 forms are found the marks of the soris but there are 

 no spores there. M. Drurey, in his excellent fern book 

 gives a comprehensive account of this peculiar growth, 

 called apospores. 



In the second case the abnormality generally affects 

 the top of the fronds, pinna?, or pinnules, and when not 

 dwarfed to a crested bunch or the pinna? along the stem 

 reduced to a rudimentary state the middle or lower 

 parts of the fronds are normal as far as nervation is 

 concerned. Where the frond is affected the nervation 

 is in the form of a net work more or less branched in 

 all directions and the spore dots (soris) are fewer and 

 irregularly set while in that part of the frond not 

 affected they are more numerous, normally set and of 

 normal form; therefore, the spores taken from the 

 normal part of an affected frond will give, by seeding 

 a much larger proportion of normal plants that will be 

 gol from spores taken from the affected parts where 

 the nervations begin to branch, and upward from this 

 point will be given a great many abnormal plants, and 

 tin' few normal ones included may be the result of 

 spores blown over the whole plant from the normal 

 portions. The spores taken from the whole frond thus 

 affected, in Athyrium iel. foem. especially, will grow 

 so many normal plants that they will kill the abnormal 

 ones— which arc always weaker — unless they are de- 

 stroyed as soon as they can lie recognized. These facts 

 apply mostly to hardy IVrns — athyrium, seolopendrium, 

 some polystiehurn and polypodium which are most 

 liable to change, hi nephrodiums abnormalities are near- 

 ly all reproduced identically from spores taken from all 

 parts of the frond and normal plants are seldom found 

 among seedlings. They are also very difficult to cross. 



Accepted theories have been combatted of late and 

 heredity has been spoken of, but until more certain facts 

 bearing upon the case have been obtained no definite 

 conclusion can be made; animal life is not vegetable 

 life; especially is the dissimilarity in ferns, where each 

 little spore is an individual. Raising abnormal forms 

 of ferns from spores is like most other things — you can- 

 not expect much success right off. Every fern grower 

 knows that disappointments and deceptions follow one 

 after the other and trying and trying again are neces- 

 sary before any results are reached, and a curious fact 

 is that after working for some time in that direction 

 the surrounding conditions become seeminglv saturated 



with the tendency to abnormality and abnormal fern> 

 will grow everywhere you put some spores. 



In the raising of new forms in ferns chance has much 

 to do, but there are some natural laws one has to recog- 

 nize. 



1. A normal fern will, with very few exceptions, re- 

 produce itself identically. 



2. Two or more species from a same genus seeded 

 together reproduce the same species mixed together with 

 'sometimes — but not as a rule — hybrids. The fecunda- 

 tion in ferns is such a minute thing that you cannot de- 

 pend on it. 



3. A single abnormal frond found on a plant — usu- 

 ally a forked frond — does not reproduce itself. 



4. An abnormal fern found in nature which has all 

 its fronds altered in the same way gives, by seeding, 

 more or less abnormal plants resembling the parent, 

 with many normal ones. Sometimes they give new 

 forms. 



5. The selected altered ferns from that product give 

 more than fifty per cent, altered ones, with some that 

 are better. After that they reproduce themselves nearly 

 identically through selected spores. 



6. Two abnormals, wild forms, of the same species 

 seeded together will give about one-half normal plants; 

 ;the other half will resemble the parents, with a few 

 other forms. 



7. A few of these new forms seeded together give 

 many other new forms, with a loss proportion of normal 

 plants. These new plants show great sensibility to vari- 

 ation and the result of seeding them together is scarcely 

 two plant,- alike in the progeny, the number of normal 

 ones, if the spores have been well selected, being very 

 small. These observations have been made with the 

 hardy ferns before mentioned and it is shown that most 

 of these abnormal hybrids will be constant forms. 



A few words about hybridizing ferns may not be out 

 of place here. Everybody who handles ferns is sup- 

 posed to know thai when a fern spore finds itself in a 

 suitable place it develops in a number of cells and takes 

 a heart-shaped form called prothalium, which adheres 

 to the ground by little hair-roots. On the under surface 

 of tin' prothallus are situated the reproductive organs: 

 male antheridium containing the antherozoids. the re- 

 productive agent, and the archegonium, tin: female or- 

 gan containing the embryo seed. If through 

 the dew moisture of the under surface of the pro- 

 thallus the movable fibratile little antherozoids are 

 carried to the opening of the archegonia. when 

 they enter fecundation takes place. Now, to hy- 

 bridize ferns it is necessary that the antherozoids from 

 one prothallus, the growth of a spore from one fern, 

 finds its way to the archegonia of another prothallus 

 which has grown from a spore of another fern. These 

 organs being so extremely minute cannot be handled 

 like the pollen of a flower and therefore hybridization 

 in ferns is always a very uncertain possibility. 



The female organs being situated within the indenta- 

 tion of the heart-shaped or top part of the prothallus 



