2IO 



Journal of Agricultural Research 



Vol. XIII, No. 3 



Two kinds of spores are found both in the pycnidia on the host and in 

 culture media: An egg-shaped to spindle-shaped spore, and a much 

 longer, slender, curved, sickle-shaped, or hooked spore (fig. i, B). The 

 former are designated by Diedicke (5) as a spores, and measure un- 

 stained 5.5 to 8.8 by 1. 8 to 3. 6 /x, the average size being 2 by 5.7 /x. Stained, 

 5 to 5.8 by I.I to 1.2 p.. They are hyalin, nonseptate, contain two to 

 three oil drops (tested with Sudan III), and a deeply staining nucleus. 

 They are borne on straight or slightly curved basidia (fig. 2, B) measur- 

 ing 0.5 to 2 by 9 to 20 fx. The second form of spore 

 which is found in the same pycnidium with the a 

 form, Diedicke calls jS spores and Shear (5) scolecos- 

 yf lllAl ^ ]/ pores. Reddick (2) regards them as free paraphyses. 

 Shear states that — 



The term ' ' scolecospore "is applied to these long, slender, crooked 

 bodies tentatively to distinguish them from the ordinary pycnos- 

 pores, because we regard them as reproductive organs, though they 

 have not yet been found to germinate under the ordinary cul- 

 tural conditions in which the other pycnospores germinate . . . 

 true paraphyses are not normally abstricted and set free as these 

 are, and occur typically only in connection with the asci, though 

 the apparently sterile hyphae sometimes found intermixed with 

 sporophores in pycnidia and acervuli, have been so designated 

 by some mycologists. These slender, curved spores are evidently 

 identical in character and origin with the so-called stylospores of 

 Diaporthe as described by Nitschke [7], the other pycnospores 

 being called spermatia by him. 



The scolecospores are hyalin and contain one to several 

 oil drops, often none, and most rarely a very pale-staining 

 nucelus may be seen. They measure unstained 1.6 to 2.4 by 14 to 

 33.6 IX, average, 1.9 by 22 /x; stained, 0.6 to 0.8 by 13.2 to 23.1 ju. They 

 are borne on short, tapering, occasionally almost pyriform basidia meas- 

 uring 2.2 to 2.7 by 5.5 to I I.I M (fig. 2, A). The scolecospores occur in 

 less number always than the other kind of spore and pycnidia have been 

 found containing no scolecospores at all. No pycnidium has been found 

 with only the scolecospores present, though there are chambers within the 

 multichambered pycnidia which do contain only the scolecospores. 



In some culture media a raised stroma is formed in which the pycnidia 

 develop and in others the stroma is absent. 



The spores are extruded in irregular droplike masses, cream, waxy- 

 yellow or amber in color, or in definite threadlike form, measuring 10 

 to 25 mm. in length. 



TECHNICAL DESCRIPTION OF THE FUNGUS 



All attempts toward finding an ascogenous form of this fungus have 

 been unsuccessful. Inasmuch as it differs from all other fungi so far 

 described as infectious to K. latijolia, and as the genus in which it must 



Fig. 2. — Pkomopsis 

 kalmiae: A , Scole- 

 cospores and ba- 

 sidia; B, the ordi- 

 nary pycnospore 

 and basidia. X 

 850. 



