380 



THE AilERICAN 



place, and the ice does not block up the harbor 

 for several weeks after boats cease to run to 

 Green Bay city. Do the befoi-e named plants 

 have a double season of flowering in this locality? 

 The varied hues of the foliage of trees, especi- 

 ally the smaller species of Maples, was very 

 beautiful, clearly showing that the change in 

 the color of the leaf is due to an actual ripening, 

 and not to the action of frost. 



EUE-LEATED SPLEENWORT. 



{A.ple, 



L.) 



VILLIAMSON, LOUISVILLE KV. 



Rue-Leavid Spleeuwort (Aiplcnium ruta-miiraria, L.)« 



This fern is a spleenwort, belonging to the 

 genus Asplenium of the gi-eat group of Polypo- 

 daceus Ferns. This group is distinguished from 

 the other two groups, Osmundacem and Ophio- 

 glossacecB, by having their spore cases girt with 

 an clastic ring. 



The word Asplenium was applied by old au- 

 thors to those kinds of ferns that were supposed 

 to possess some virtues in curing diseases of 

 the spleen. Modern authors classify the Spleen- 

 worts and all other Ferns on a more definite 



•Explanation of the Figuhe — a, I'liint, natural 

 bj back of the frond, showing the sori or fruit dots; c, u 

 side of the fronds; d, youn^ fronds growing from the t 

 rootstock showing their cnoinate vernation; e, old ft 



principle, that is, the arrangement of the fruit, , 

 or sori, and the form of the indusium., or fruit- 

 cover. 



Asplenium ruta muraria is a small evergreen 

 fern two to four inches long ; root tufted, flbi'ous ; 

 stalk smooth, with one groove on the upper side, 

 slightly round on the back; fronds bi-pinnate 

 below, simply pinnate above ; pimiules i-hombic- 

 wedge-shaped, toothed at the apex, sometimes 

 deeply cut, without a mid-rib, the veins rising 

 irregularly tt-om the base of the pinnule towards 

 each serrature ; involucre or indusium elongate, 

 opening inwardly, with a sinuated margin, espe- 

 cially so when burst ; whole plant smooth and 

 having a glaucous-green color. 



I found this fern and the delicate Rock-brake 

 (Pellea gracilis') growing on the same rock, in 

 a very exposed situation. Their tufted roots 

 were embedded in the crevices of the rocks, so 

 that it was with some difficulty that good speci- 

 mens could be obtained; but by bieaking the 

 rock and using a little patience the difficulty 

 was overcome. On visiting the same district 

 on the 4th of July, I found some beautiful spe- 

 cimens growing in a sheltered situation; their 

 roots were embedded in the moss wliich grew 

 upon the rocks. Some of the fronds measured 

 fully five inches in length. 

 In England and Scotland this fern is named 

 the Rue-leaved Spleen- 

 wort, or "Wall-rue Fern. 

 It is what is termed a 

 mural species, from its 

 L.ineral habitat, grow- 

 ig usually on old walls. 

 It is found very fre- 

 quently on old castles, 

 old towers, and old 

 '■S.»u;/li<"'\/:.Su[Vu,d,ttS bridges. Lime appears 

 """S""- to be one of its chief 



elements of nourishment, at least it is always 

 found in a limestone i-egion. 1 have seen an old 

 Roman bridge in Scotland almost covered with it. 

 Two othe^ peculiar situations in Scotland in- 

 terested me very much : one was on the top of 

 an old round tower, about eighty feet high ; the 

 other in a well about four feet from the sur- 

 face. There were only a few plants growing 

 in each place, and no others within a radius of " 

 fifteen miles. It is strange that the spores would 

 have settled iu two situations so extremely dif- 

 ferent. The specimens growing in the well were 

 large, soft, and delicate ; those on the tower 

 small and crisp. 



The specimen in my herbarium is three and 

 a half inches long, and something similar to the 

 above illustration, with this exception, the pin- 



[Fig. 230.] 



1 



