3 o6 SYSTEMATIC 



The following is the main outline of Koerber's classification: 



Series I. Lichenes Heteromerici. 



Order I. Lich. Thamnoblasti (fruticose). 



Order II. Lich. Phylloblasti (foliose). 



Order III. Lich. Kryoblasti (crustaceous). 

 Series II. Lichenes Homoeomerici. 



Order IV. Lich. Gelatinosi. 



Order V. Lich. Byssacei. 



With the exception of Order V all are subdivided into two sections, 

 "gymnocarpi" with open fruits and "angiocarpi" with closed fruits, a 

 distinction that had long been recognized both in lichens and in fungi. 



e. NvLANDER. The above writers had been concerned with the inter- 

 relationships of lichens ; Nylander, who was now coming forward as a 

 lichenologist of note, gave a new turn to the study by dwelling on their 

 relation to other classes of plants. Without for a moment conceding that 

 they were either algal or fungal, he yet insisted on their remarkable affinity 

 to algae on the one hand, and to fungi on the other, and he sought to make 

 evident this double connection by his very ingenious scheme of classfication 1 . 

 He began with what we may call "algal lichens," those associated with 

 blue-green gonidia in the family "Collemacei"; he continued the series to 

 the most highly evolved foliose forms and then wound up with those that 

 are most akin to fungi, that is, those with least apparent thalline formation 

 according to him the " Pyrenocarpei." 



In his scheme, which is the one followed by Leighton and Crombie, the 

 "family" represents the highest division; series, tribe, genus and species 

 come next in order. We have thus : 



Fam. I. Collemacei. 



Fam. II. Myriangiacei (now reckoned among fungi). 



Fam. III. Lichenacei. 



This last family, which includes the great bulk of lichens, is divided into 

 the following series: I. Epiconiodei; II. Cladoniodei; III. Ramalodei ; 

 IV. Phyllodei; V. Placodei; VI. Pyrenodei. It is an ascending series up 

 to the Phyllodei, or foliaceous lichens, which he considers higher in develop- 

 ment than the fruticose or filamentous Ramalodei. The Placodei include 

 four tribes on a descending scale, the Lecanorei, Lecidinei, Xylographidei 

 and Graphidei. The classification is almost wholly based on thalline form, 

 except for the Pyrenodei in which are represented genera with closed fruits, 

 there being one tribe only, the Pyrenocarpei. 



Nylander claims however to have had regard equally to the reproductive 

 system and was the first to give importance to the spermogonia. The 

 classification is coherent and easy to follow, though, like all classifications 



1 Nylander 1854. 



