278 Journal of Agricultural Research voi. vi, no. 8 



9.7/i by 90.67 to i3i.37,u (7.4 to 8.7^1 by 108.9 to ii-j.6,a); paraphyses numerous, fila- 

 mentous, swollen at the ends or recurved. Spermogonia intermixed averaging 5 mm. 

 in length; spermatia elongated, straight, sometimes slightly curved, hyalin, contin- 

 uous, averaging i by 8,u. 



Type locality: Sumpter, Oreg., Whitman National Forest. 



Habitat: Living needles of Pinus ponderosa. 



Type material deposited in the Office of Investigations in Forest 

 Pathology, Bureau of Plant Industry, Washington, D. C, and in the col- 

 lections for study in the Laboratory of Forest Pathology in the same 

 office, at Missoula, Mont. 



GENERAL BIOLOGY OF THE FUNGUS 



The apothecia of the fungus are the most conspicuous of any of the 

 group on pines in the West (fig. i ) . From new infections of the previous 

 year fully mature apothecia with well-developed spores (fig. 2) may be 

 collected in early spring. From this time on the longitudinal split on the 

 medial line of the apothecium is plainly visible, and may remain open or 

 closed, depending on the humidity of the atmosphere. 



iflG. I. — A side view of two apothecia oi Hypoderma deformans on needles of Pinus ponderosa, showing 



the longitudinal medial split. 



The splitting of the epidermis on the needle directly on the medial line of 

 the apothecium is a characteristic shown by nearly all of the Hysteriaceae 

 and in a few cases seems to be governed by a particular structure of the 

 overlying layers of the apothecium. Thus, Von Tubeuf ^ points out that 

 the pseudoparenchymous covering of the apothecium of Lophodermium 

 pinastri (Schrad.) instead of being one continuous homogeneous tissue 

 is made up of two parts which come together on the middle line of the 

 fruiting body. The edges of the two parts interlock by a series of short 

 papillae. It is on the line of these papillae, when the pressure within the 

 apothecium becomes suflicient, that the epidermis of the needle ruptures. 

 In Hypoderma deformans the rupture of the apothecium is apparently 

 made easier by the coalescence of filamentous elements springing from the 

 floor of the apothecium and meeting with the darker tissues of the 

 apothecial covering above. Owing to a differentiation of the covering 

 of the apothecium at the point of union a line of rupture is formed. 



1 Tubeuf, Carl von. Studien iiber die Schuttekrankheit der Kiefer. In Arb. Biol. Abt. Land- u. 

 Porstw. K. Gsndhtsamt., Bd. 2, Heft i, p. 22, 1901. 



