482 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



and species of Narcissus and Gladiolus. Eriksson * gives as an 

 additional host /. atomaria, and Lind f mentions among other species 

 I. propendens I and I. plicata.^ Chlorogalum angustifolium,\\ Hemero- 

 callis fulva, ^ Gemmingia chinensis, Iris Swertii, I. benacensis, and /• 

 orientalis are recorded as hosts in America, ff Many exsiccatae 

 have merely the generic name of the host plant. 



History and Nomenclature. — The species of Heterosporium causing 

 the disease under consideration is most commonly referred to as 

 Heterosporium gracile (Wallr. ?) Sacc, although very frequently the 

 query is omitted. In considering the history of the fungus it was 

 apparent that the specific name would have to be rejected if it were 

 attributable to Wallroth. There is a great objection to altering 

 such a well-known name, and our reasons for retaining it are given 

 below. Several points with regard to the genus Heterosporium which 

 appear of sufficient interest are also noted. 



The description of Wallroth's fungus occurs in his " Flora Crypto- 

 gamen," ii. (1833), p. 164, under the genus Helmisporium (" Helmi- 

 sporium, Lk. obs. Helminthosporium Pers. myc. et Lk. sp. Coelosporium 

 Lk."), and is as follows, " Helmisporium gracile W., rhabdis simphcibus 

 nodosis gracilescentibus erectus peliucidis fasciculatis, appendicibus 

 sporomorphis circa apicem congestis ovatis minimis 3-4 septatis utrin- 

 que obtusiuscuhs, rhabdorum molem subaequantibus — Helmisporium 

 gramineum W. ohm. Ad foHa vaginasque graminum cereahum 

 sicca et Iridum foHa passim." There are in this description several 

 points which suggest the Iris disease, but perhaps the fact that the 

 diagnosis refers to a black mould which occurs on Iris leaves has led to 

 the idea that it was identical with the fungus we are considering. But 

 it does not seem that " appendicibus sporomorphis circa apicem con- 

 gestis ovatis minimis 3-4 septatis " can possibly refer to a fungus spore 

 of 30-80 /X X 15-20 /X {i.e. visible to the naked eye) generally biseptate 

 and borne singly at the tips of the conidiophores. The fungus is much 

 more frequently referred to the genus Brachysporium and becomes 

 Brachysporium gracile (Wallr.) Sacc. J | It is clear that both these specific 

 names cannot be based on the original description. It would seem 

 that the description applies much better to the Brachysporium than it 

 does to the Heterosporium in every way. Lindau refers to the spores 

 of Brachysporium gracile thus : — " Konidien am Scheitel des Tragers 

 * Fung, parasitica scandia, No. 398. 



•)■ Danish Fungi as represented in the Herbarium of E. Rostrup. 

 X Mr. W. R. Dykes, in a letter to me, queries what plant is intended by 

 this name. 



§ De ThOmen, Mycoth. Univ. No. 876, records Helminthosporium gracile on 

 leaves of /. biglumis. 



II Flora of Sequoia gigantea Region, No. 2033. 



^ Ellis et Everhardt, North Amer. Fungi, 2nd Series, No. 2189. 



** E. Bartholomew, Fungi Columhiani, Nos. 1828, 2627, 2731, and 2732 

 respectively. 



tf The pubHshed sets were consulted in the Botanical Department of the 

 British Museum. 



XX E.g. Sacc. Syll. Fung. iv. (1886), p. 430, where there is a note added, " cfr. 

 Heterosporium gracile," which is given torn. cit. p. 480 as Heterosporium gracile 

 (Wallr. ?) Sacc. 



