The Gardenia-Rootdisease''. 



The Gardeners' Chronicle, London, Vol. I. Third Series, Jan. to June 1887, p. 488—4811. 



This disease is occasioned by Heterodera radicicola, a small worm belonging to 

 the order of the Nematoids, and is also related to the Heterodera Schachtii, 

 Schmidt, the much dreaded Beetroot parasite. Other and more generally known 

 allies are Anguillula devastatrlx, the wide- spread plant-destroyer from our fields 

 and gardens, and Anguillula aceti, from the vinegar-bottle of our dinner-table. 



A great number of plants are affected by the same worm which affects the 

 Gardenia roots, and the morbid condition caused by the worm is curiously similar 

 in widely different plants. The occurrence of Heterodera radicicola has been ob- 

 served by myself and others (especially Licopoli, Frank, and Carl Muller) in the 

 following plants: — 



Monocotyledons. — Poa annua, P. pratensis, Elymus arenarius, Triticum repens, 

 Saccharum officinale, Musa rosacea, M. dacca, Phoenix dactylifera, and Chamaerops 

 humilis ). 



Dicotyledons. — Clematis vitalba. Berberis vulgaris, Balsamina hortensis, Vitis 

 Labrusca, Cistus aconitifolia, Euphorbia cyparissias ( ?), Daucus Carota, Angelica 

 sylvestris, A. archangelica, Carum carui, Sempervivum tectorum, S. glaucum, Sedum 

 reflexum, Onobrychis sativa, Ornithopus sativus, Trifolium incarnatum, T. pratense, 

 Medicago sativa, Erythrina crista-galli, Dodartia orientalis, Coffea arabica, Ixora 

 aurea, I. flammea, I. crocea ( Hamiltonia spectabilis), Dipsacus fullonum ( ?), Plantago 

 lanceolata, Cucumis sativus, Taraxacum officinale, Lactuca sativa, Cichorium Inty- 

 bus, Cirsium arvense, Sonchus macrophyllus ; and probably the same parasite occurs 

 in many other plants. especially in hothouses. 



It may be seen from our fig. 93 that the effect of the parasitic worm on the 

 Gardenia roots — and so it is in other plants — consists in a remarkable and very 

 irregular hypertrophy or tumour of the root-tissues, which runs either along the 

 f uil length of the root or is localised in small circumscribed places in this organ, 



') References may be made to Carl Muller, Neue Helminthocecidie und deren Erzeu- 

 gung, Berlin 1883; to Frank, Ueber das Wurzel-Aelchen, &c, Berichte d. Deutsch. Bot. 

 Gesellschaft, Bd. 2, p. 145, 1884; and to Carl Muller, Bemerkungen :u meiner Dissertation 

 &c, Berichte d. Deutschen Bot. Ges., Bd. 2, p. 221, 1884. 



2 ) Treub considers the Heterodera of Saccharum officinale as a new species, called 

 by him Heterodera javanica ( Ann. d. JarJ. Bot. d. Buitenzorg, vol. VI., p. 4, 1886), but this 

 assumption is based only on the microscopic measurement of his material in compari- 

 son with the numbers given by C. Muller for the H. radicicola. My own numbers 

 regarding the last species are much nearer to those found by Treub than to those of 

 Muller. 



