106 



(Tairsonemus) and have grDwn out to short, broad papillae with 

 a granular outer surface-^, Tarsonemus induces similar papil- 

 lae on other graraineae also ( Stipa papillate . Triticum repens) . 



In the majority of cases, the Brineura turf consists of 

 slender, cyllndrioijl hairs of equp.l thickness and uith rounded 

 tips. In the leo-ves of Alnus, Tilia, Pagus, and other trees, 

 the turfs occur on the upper or under side of the leaves, more 

 rareljr on corresponding areas of both leaf -surfaces (Compare 

 figc 38). tPhey form extraordinarily thickfelts, since all or 

 nearly all the opiderra?.! cells on the infected plaoe In the 

 leaf hypertrophy as is shorrn in the illustration, 



The non- cylindrical hairs, occurl^ing on the leaves of 

 Pru nus Padus . Betula, Acer a^^d others, have different forms in 

 ihe different Erineum-galls. Either hP.irs i^ith slender bases 

 are found, T^rhich grow broader torrard the tip and end v:ith a 

 round tip, or thrtse ■v7ith a sharply set-off, ball-like or roller- 

 like head, or irith a flat and mushrooft-like one (Compare fig. 

 39), or they are depressed on the top, thereby becoming cap* 



(113) like. If a tendency towards branching shows itself, lobated 

 forms are produced (Pig. 44a). I observed unusual hair forms 

 in the case of an Erineurn of Alnus latifolia , which produced a 

 powdery coating •n the underside of the lear. The hairs, by 

 their ramification, had assumed a racemose form and the great- 

 est variety was visible among them. A few hairs of this Erin- 

 sum are shown in Pig. 40. In contrr.ot to the Erineurn galls 

 with slender, cylindrical hairs, bnly isolated epidermal cells 

 have been transformed hypertrophically in those forms which 

 have spherical or toushroom-like elements, as shown by Prank, 

 loo. cit, (fig. 39), \7hen the hairs are close together, their 

 heads may often touch one another, be flattened out in one an- 

 other, or even dovetail together with their short processee/ 



Per the histology of the single Erineum cells,- as in 

 the case of other gall-hypertrophies,- the abundant supply of 



(114) nutritive substances is important, which is connected Yrlth tne 

 growth of the infected cells. The abundance of nutrition is 

 demonstrated by the growth in thickness of the walls and es- 

 pecially by the storing up of proteins, starch and fatty oil 

 in the interior of the hair cells. 



The thickening of the wall is less conspicuous in the 

 simple cylindrical forms than in those distended like clubs. 

 Especially the parts of the wall toward the outer sxdeare 

 often very thick. Thickened and pitted also are the side ana 

 inner walls of the epidermal cells which have grown out to 

 Erineum sacs, but are still united with the tissue of the epi- 

 dermis. Similar changes occur at times in places ^nere ^pie 

 Erinetun hairs touch one another. According to Prank the 

 slender ha-irs of the linden Erineum (" Erineum tiliae ") can co- 

 alesce at the places of contact and form corresponding p^ts, 

 just as do the tyloses which touch each other inside of "'jh© 

 lumen of a duct (p. 100). In the case of club-like hairs, the 

 heads, provided with short outgror;ths, sometimes coalesce and 

 furnish a kind of pseudo-par ench2nnatic tissue; Prank observed 

 pit-like thin places in the membranes of the contact-surfaces. 



■'• MassaloiCigo, Intorno alV acaroceoidio della Stipa pen- 

 Hatfe L,, caugato dal Tarsonemus Canestrinii, N. Giorn. BQt. 

 ,, JtJil., 1897^ Jt.i^/ Vol. IV, p. 103. 



