60 



grains^- disappear and the nucleus breaks dovm. Later we will 

 again refer to the "tendency" of orchids toT/ard the formation 

 of netted duct cells. (Chap. IV. 4). 



Cellulose deposits without any regular arrangement and 

 without bordered pits occur in very different plants rnd after 

 very different kinds of disturbances, 



(62) These cellulose deposits form an especial group, and are 

 produced by the penetration of foreign bodies into the living 

 cell. The form of the newly-produced cellulose masses is then 

 determined not by the quality of the cells forming the cellu- 

 lose, but by the form of the foreign body. As is well knorm, 

 the crystals of calcium oxalate within the cells are often sur- 

 rounded by a cellulose mantle, which coalesces in one or more 

 places with the wall of the cell containing it, (Rosanoff's 

 crystals). Other paraplasmatic cell enclosures are also sur- 

 rounded at times with a cellulose covering, such as the oil 

 drops in the cells of the Piperaceae, Ajpistolochiaceae, Laura- 

 ceae. Similar cellulose formation is Incited in abnormal cases 

 when fungus hyphae penetrate into the protoplast. First of all 

 a cellulose button forms at the place of infection. Later a 

 sheath is produced around the penetrating hypha, and passes 

 through the whole cell as a tube, when the hypha has traversed 

 the cell*'-. W. Magnus saw Inside the cells of Neottia Nidus 

 avis, attacked hy the fungus, clumps composed of fungus ancL cy- 

 toplasmic fragments changing Into cellulose . 



The cellulose sheaths of cells infected by fungi here des- 

 cribed should not be confused vi^ith the coverings which clothe 

 the sting canal of various plant lice throughout the lumina oif 

 the cells and the intercellular spaces. Their mention may )» 

 a propos here, since they were considered earlier to be path- 

 ological cellulose structures. Millardet designated them as 

 "bourrelets de^^ cellulose", and Prillieux^ made the same mistake. 

 According to Busgen's thorough investigations, no product of 

 plant cells is involved in the sheath-like structures, but an 

 excretion of the parasite, which hardens after the withdrawal 

 of the sting from the bundle of bristles, surrounds it as a 

 firm tube and acts as s protection . The sheath substances 

 gives distinct protein reactions, 



^ Besides DeBary, Pilze, p. 422 and Brefeld, Brandpilze, 

 compare also Weber, Ueb. d, Pilz der Wurzelanschwellungen von 

 Junous bufonius. Bot. Zeitg. , 1884, Bd. ZLII, p. 369; Smith; 

 The Haustoria of the Erysipheae, Bot, Gaz. ,1900, Vol. XXIZ, 

 p. 153; Jeffrey, The gametophyte of Borychium virginianum, 

 Univ. of Toronto Studies, Ur, 1, 1898, and many others. 

 (Jeffrey states that a sheath of cellulose is formed onj-y in 

 case of the permeation of the cutinized walls in the interior 

 of the cell). Compare also the statements in W. Magnus. 

 (Kext note). 



Studien an d, Mycorrhiz^i f, Heottia IIi4»^ avijs. Prings- 

 heifli's Jahrb. f, wiss. Bot., 1900, Bd. ZZXV^ p. 205, 



It I 



^ Mi;Lla3j'det . Hist, d', princip, var. et especee de vignes 



d' origin© americ. qpiir^ si stent au Phylloxera, Pa^is, Bordeaux. 



Milan, 1885, p. VIII (quot?ed from Busgen, see nejKt note). 



PirLllieux, Etudes d. alterations prod, d, le bois du pommier 



etc. Ann. Inst. nat. agrb$. , 1877-1879, i:, II, -p. 39. 



'* Busgen, Der Honigtau, biol. Unliers. uj>. Pfl. und 

 Pf lanzenlause . Jepa 1890* 



