34 



Garden and Forest. 



I Number 466. 



the fruits, Oranges figure conspicuously at this season, and 

 enormous trees are everywhere seen heavily freighted with 

 them. The Tangerines are plentiful and good ; the Mango is 

 almost over, and so also the Alligator Pear. Guavas and cus- 

 tard Apples are plentiful ; Strawberries are ripening fast, and 

 there is plenty of Apples and Walnuts. Coffee is grown abun- 

 dantly. Many of us cultivate our own Arrowroot, which is 

 excellent ; and much use is made of the so-called Cape Goose- 

 berry (Physalis Peruviana). The Citron is only seen in gar- 

 dens here and there, but grows perfectly, and is most excel- 

 lently candied in the island, as are also many other fruits in 

 their season. 



Nectria on Currant Canes. 



FOR a number of years there have been complaints 

 from several places in the state of New York of a 

 serious trouble with Currants. Nearly two years ago, from 

 material sent me, it was evident that the trouble was due 

 to the parasitism of a species of Nectria. Entire bushes 

 were received, and while the larger part of the canes were 

 dead, most of the roots and some of the lower ends of the 

 canes were still alive. From these living parts of the canes 

 new shoots had developed ; in some cases a number of 

 small shoots quite close together, so that the appearance 

 was something like that presented by the so-called witches' 

 brooms. It is not a true broom, however, since the devel- 

 opment of the new shoots is not stimulated by the action 

 of the fungus, but is the endeavor of the plant to produce 

 new shoots or replace the dead ones. 



The diseased plants first show a yellowing of the leaves. 

 The leaves later wither and fall. The fruit often reddens 

 prematurely, and if the injury is serious some time before 

 the time for ripening the berries often wither. Sometimes 

 the canes are killed before the leaf and flower-buds are 

 fully opened, and in such cases the dried buds with partly 

 opened leaves remain on the canes. Infection probably 

 takes place through some injured or cut surface, and cut- 

 tings from diseased plants, or from apparently healthy ones 

 in places where the disease is present, are probably one 

 prolific source of the trouble. 



Dr. E. J. Durand, formerly assistant botanist for the 

 Experiment Station, and now instructor in botany in Cor- 

 nell University, was detailed to study the disease. He 

 visited the districts where the trouble existed, made a care- 

 ful study of the external symptoms and collected material 

 for a study of the life-history of the parasite. Artificial pure 

 cultures of the fungus were made, and stems containing 

 the conidial stage were placed in a cool, shady place in a 

 small wood in order to obtain a larger number of the per- 

 fect stage of the fungus, some of this having been found 

 on the canes from the field at the time the plants were 

 obtained. 



Two species of Nectria were present, and some careful 

 study was necessary in order to separate the two conidial 

 forms and properly correlate them with the perfect forms. 

 One of the fungi proved to be the well-known N. cinna- 

 barina, which is widely distributed both in Europe and 

 America as a saprophyte, but also occurs as a parasite, 

 according to Hartig and others. This Nectria was con- 

 nected with the conidial form known as Tubercularia 

 vulgaris. This forms bright pink elevations, which have 

 their origin from the mycelium which grows in the cam- 

 bium of the cane. These elevated masses of the fungus 

 rupture the bark, and are thus exposed. The spores are 

 borne at the outer surface of this mass, and are thus easily 

 freed and carried to other canes. The perithecia of the 

 perfect form are later borne on this stromatic mass, and are 

 in the form of oval flasks, with a minute opening at the 

 free end. Inside of these flask-shaped fruit bodies are 

 numerous elongated club-shaped sacs, each of which con- 

 tains eight spores, called ascospores. These ascospores 

 are different in form from the conidia, and are composed 

 of two cells, while the conidia are one-celled. 



The other fungus was lighter pink in color than the 

 Nectria cinnabarina, and its conidial stage did not appear 

 in the form of a prominent stroma. The perithecia, how- 



ever, resemble those of the N. cinnabarina rather closely, 

 and care is necessary to discriminate between them 

 without recourse to the microscope. Here, however, 

 we find a ready means of separating the two, for the 

 ascospores of this one are many-celled, the divisions in 

 the spore running both longitudinally and transversely, 

 while the ascospores of N. cinnabarina have only one 

 transverse partition. This fungus is the Pleonectria bero- 

 linensis, Sacc. 



The most serious outbreak of the disease occurred in 

 western New York, where a plot of Currant bushes of about 

 three acres was affected. At the time the place was vis- 

 ited, in 1895, the bushes upon two acres had been destroyed 

 and the remainder were badly diseased. A large number 

 of cuttings taken from these plants made very little growth 

 and also exhibited symptoms of the malady. The fact that 

 cuttings showed the disease so soon indicates that plants 

 should not be propagated from diseased stools or even 

 from apparently healthy plants in the vicinage of infected 

 ones. Mayer has shown that this fungus gains an entrance 

 to living plants through wounds or cuttings. Once in the 

 tissue it may become perennial, so that the twigs may con- 

 tain the fungus at the time of making the cuttings for trans- 

 planting. Since the fungus may become perennial in the 

 tissues affected, plants cannot be cured. It would probably 

 be better to destroy them and for a few years plant some 

 other crop in the ground. 



The subject is one of such importance that Dr. Durand 

 will prepare a monograph upon it for distribution by the 

 Experiment Station. . 



Botanical Department, Cornell University. George F. AlkinSOIl. 



T 



New or Little-known Plants. 



Mespilus grandiflora. 



HIS is a small tree, distinguished by ovate-oblong, 

 crenate and occasionally obscurely lobed dark green 

 leaves pubescent below, foliaceous stipules, large pure 

 white flowers, which are solitary or produced in few-flow- 

 ered clusters, and lustrous, erect, russet-brown punctate fruit, 

 slightly flushed with red. It has been an inhabitant of 

 European gardens for at least a century, but its orgin is 

 uncertain. At different times it has been considered a 

 European and a North Amercan species ; C. A. Meyer 

 believed that it was a native of the Caucasus, and Karl 

 Koch and many other authors saw in it a possible hybrid 

 between the European Mespilus Germanica and either Cra- 

 taegus stipulacea, a tropical American species, or the eastern 

 American Crataegus tomentosa. We have no views to offer 

 on the origin or parentage of this tree. In habit, however, 

 in the general form and color ofthe leaves, in the flowers 

 and in the rusty color of the fruit, it bears a close resem- 

 blance to Mespilus Germanica. The fruit, however, is 

 smaller, distinctly punctately dotted, like the fruit of our 

 Crataegus punctata, lustrous and tinged with red, and the 

 opening of the calyx-tube is much narrower. In the Arnold 

 Arboretum, where this tree is well established, it grows 

 more vigorously than Mespilus Germanica, and its greater 

 hardiness might indicate an origin in some cold country 

 like the Caucasus, or a cross, if the plant is a hybrid, witli 

 one of our northern species of Crataegus. 



But our object in publishing the figure on page 35 of this 

 issue, which is a reproduction of a drawing made by Mr. 

 Faxon in the Arnold Arboretum, is not to discuss the origin 

 and history of this tree, but to call attention to its value in 

 northern shrubberies and plantations, where it grows 

 rapidly and is not attacked by the fungal diseases which in 

 this climate defoliate at midsummer several species of Cra- 

 taegus ; the flowers are large and abundant, but the leaves, 

 like those of many of the Old World trees, shrivel, turn 

 brown and fall in the autumn without assuming the bright 

 colors which make most North American and eastern 

 Asiatic trees and shrubs such beautiful objects in the autumn 

 landscape. 



