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Botany. — "Exospoi-ina T. ar if is; Oud. — A iii'v wicrosropic 



fiiiiijiis itccii rriiKi on llic Larch atnl rcnf in jUrKnis In lliis liwi'. 

 \\\ Prof. V. A. .1. A. OlDKMANS. 



Oil .Iniie 11, 1903, Air. ('. A. O. Hkins (•(i11ccIc(| (hi the estate 

 "(Ic (ii-(i()te jiiiiitc" al Xiirispect and sent to iiic a miiiihei' of needles 

 ajid twius of fli(^ coiiiiiioii Larch (fjtrlv ilccidiin =^ Lartr I'/iro/xfr'a), 

 llie former of wliicli, alllioii,t;ii tliev l»eioii,i>-ed to recently ftrowii 

 dvvarfslioots, had for the «irealer jiart a sickly appearance. an<l had 

 e\clian^-e(l their ÜLilit-urccii coh)iir for a lii;ht-l)ro\\ ii one. 



The question naturally arose ; what could he the caux- of this 

 pheiionuMiou, and whether a fun.üus nii,ulit lie at the I'oot of it. 



An investigation concei-ning this matter soon showed me that the 

 twigs ^vcl•e normal, and consequently had not heen \isited hy the 

 to the Larch very injui-ions l^'zizn ( Dnsi/sci/p/ntJ WiUL'onnnn, hut 

 that the needles wei-e spotted on hoth sides, hut esj)ecially on the 

 lower side, with vei-y small hlack specks (Fig- 1). 



These sjiecJcs, s|)read at random, sometimes more, sonuMimes less 

 numerous, mostly circular, had a diameter of 100 150 n at the 

 utmost, and most resemhled Lcjitostronni- or Jy('j)tothi//-/un/-s\)vvk>^, 

 although a closer examination showed that they shared no pi-operty 

 of any im|K)rtance with these genera. They coIkm-cmI lirndy with the 

 epiderm, and it soon appeared that they had not heen hidden uiidei- 

 it and gradually h)nn<l aii exit, hut that they had existed fi'om tln^ 

 heginning on the sui-face of the needles. 



This residt was not ohtained hy examining cross-sectiojis, which 

 the \-ery minute specks did not allow to make, hut hy heating the 

 needles for a few mimites in a ten percent solution of caustic potash, 

 washing them, making them trans[)arent with chloral-hydi-ale, and 

 gently pressing them with a co\er-sli|). Under the niicroscoj»e light- 

 hrown. wavy, occasionally hifiircate<l threads or I'ihhons of varying 

 hi'eadth were seen oji the leaf, which in various places produce<l 

 little disks, from which new threads were sent out in some other 

 direction (Fig. 2). 



The threads consisted of articulate hyphae and the disks of a 

 small-celled parenchym. IJy |»ressing the hiWvv moi-e sti-onu;iy and so 

 dividing them into smallei' fragments, it appeared that they were not 

 flat hut ulohular, and that tli(\v protruded like litlle cupolas ahove 

 the e|)ideriu to which they were lirndy attacheil. 



These fragments also uaxc an opporluinty (»f gaining an idea ahout 

 the iiit<'rnal structure, of the disk>. h'roni their small-celled tissue, 

 namely, cei-tain la\tiui-ed hyphae had grown up in a close hunch, in 



