136 



A RACE OF FLOWERLESS PLANTS. 



similar histories, but their cluster-cups do not grow on 

 barberry. A fourth species, which grows on Indian 

 corn, is not known to have any cluster-cup form. 



It is easily seen by a comparison of the figures, that 

 wheat rust and apple rust belong to the same class of 

 fungi. The black rot of the grape and the black knot of 

 the plum trees both belong to another class, which have 

 one of the kinds of spores in sacks (Fig. 11 and 15). 



The black knot of the plum trees is one of our best 

 known and most destructive fungi, making plum culture 

 a failure in many places. It might easily be combatted 

 with considerable success if cultivators would only make 

 the effort. Its life history was worked out with great 

 accuracy by Prof. W. G. Farlow, of Harvard University, 

 in 1876. In the spring a new knot forms, in many cases 

 as an extension of an old one ; the branch on which it 

 forms swells and cracks open. The microscope shows 

 certain spores borne on the tips of threads and called 

 conidia (Fig. 8). The knot grows on and acquires a 

 crust-like surface which becomes marked with small 

 pimples. These pimples indicate cavities in which 

 spores are formed. Some of them (Fig. 10) contain 

 spores in sacks (Fig. 11) which become mature in Feb- 

 ruary. Other cavities contain spores of three different 

 kinds, none of them in sacks. Fig. g shows one of 

 these kinds [stylospores) which are borne on the slender 

 stalks attached to the walls of the cavity. This fungus 

 then has five different kinds of spores, two of which 

 (Figs. 8 and 11) are of special importance, the conidia 

 and the sack-spores. 



The black rot of the grape (Figs. 12-15) does not ap- 

 pear to be quite so intricate as the black knot. Two of 

 its forms are especially important, (i) the sack spores, 

 shown in a cavity, somewhat magnified at Fig. 14, and 

 simply in their sacks, more magnified, at Fig. 15 ; (2) 

 the stylospores, seen oozing out of their cavities, some- 

 what magnified, at Fig. 12, and in a section, more mag- 

 nified at Fig. 13. The latter were, until recently, the 

 only kind of spores well-known in this fungus, and are 

 the only ones seen in great abundance. They grow on 

 the leaves as well as the fruit, and naturally having a 

 different appearance on the leaves, were thought to be a 

 distinct species not particularly injurious. They were 

 therefore disregarded, and remained a constant source of 

 infection for the fruit. 



These examples are merely familiar illustrations of 

 thousands of similar cases, some of which have been in- 

 vestigated but most of which are yet but poorly known. 

 How shall such plants be named, or if, as frequently is 

 true, each form has its name or even several names, 

 what shall be the name of the fungus as a whole ? To 

 the black knot only one name was originally given, 

 Sphieria niorhosa, and when its various kinds of spores 

 were found, they were recognized as belonging to it and 

 called by its name. But the different forms of black 

 rot were at first supposed to be distinct species and they 

 received different names. The black wheat rust was 



called Piucinia graminis in 1797. A little later the red 

 rust was named Uredo linearis, being considered a dis- 

 tinct species ; but several years earlier than either of 

 these, the cluster-cup form on the barberry was called 

 Afcidinni Berberidis . When the red and the black rots 

 were found to be of the same species, there was no diffi- 

 culty about the name, because the older of the two 

 names was the one that had been given to the most 

 highly developed spores, and it is now rightfully applied 

 to both forms ; but when the cluster-cup was proved to 

 be a form of the same fungus, the question arose, shall 

 the law of priority be followed and the name be Puccinia 

 Berberidis, or shall the original name of the most highly 

 developed stage be retained ? The first name must be 

 Puccinia, because the fungus belongs in that genus ; 

 Puccinia graminis is the name still used. One of the 

 other wheat rusts was first studied in its red form and 

 called Urcdo Rubigo-vera. Afterward its black spores were 

 called Puccinia strinformis. When they were found to be 

 forms of the same species, the older specific name was 

 combined with the proper generic name, and the fungus 

 was called Puccinia Rithigo-vera ; but some claim that it 

 should still be Puccinia striceformis. 



Another question arises here. It is a necessary cus- 

 tom to append to a scientific name the name (often abbre- 

 viated) of the man who named the plant. Who is the 

 author of the name Puccinia Rubigo-vera ? Some botan- 

 ists claim that it is the man who gave the name Rubigo- 

 vera, though he placed it in another genus ; others say it 

 is the man who first put together the names Puccinia 

 and Rubigo-vera ; still others hold that both men's names 

 should be appended as authorities, the first in parenthe- 

 sis, thus : Puccinia Rubigo-vera (De Candolle), Winter. 



The black rot fungus of the grape has had more than 

 twelve different names, applied to different stages or the 

 same stage growing under different conditions, or by 

 botanists in ignorance of names previously given, or by 

 others who made too much of unimportant differences. 

 The botanist cannot ignore these names ; he must take 

 account of every one. If one of the variations is allowed 

 to stand as a supposed distinct species when it is only a 

 form of the ro'., it may be ignored in applying remedies, 

 and so remain a source of infection. This was actually 

 the case until recently with the leaf forms of the black 

 rot. 



But having once recognized any fungus in all its forms 

 and variations, and having selected the name which 

 ought properly to be retained, the other names need 

 only be recorded in a list of synonyms and laid away. 

 The most highly developed form of this fungus was the 

 last to be discovered, therefore the last to be named, but 

 fortunately all have agreed in retaining the specific 

 name of this form. 



If this is all confusion to the reader, will he not feel a 

 little pity for the botanist who is compelled to study 

 names when he wants to study plants ? 



Harvard University . A. B. Seymour. 



