74(3 (GEOLOGY UF THH YELL0WST0:NE NATIONAL PAEK. 



I'httdinis iioh'ilis Xewljy.; 1 should imt hesitate to (■(iiisi(h'i' it as i(h'iitit'al, l)ut 

 tor tlie character of the lateral nerves, which are ilescril)ed bv the author as 

 straifjht, aud termiuating in the teeth of the margin. In this species the 

 borders are entire and the lateral nerves camptodrome. The difference ma v 

 be merely casual, for one of the specimens from Troublesome Creek has 

 the close secondary veins cjunptodrome along the borders of the inner side 

 of the loljes, while on the outer side the borders are obscurely cut by a 

 few small teeth, into which the veins enter as craspedodrome. Other speci- 

 mens, thus of p]lk and Yellow creeks,^ have the characters of 1'. nohil/s." 



It would thus appear that Lesquereux himself in(diiied to regard the 

 Park specimens as being referable to PJataiins nobilis, but in the oO or more 

 specimens that I have studied frf»m this })lace I have not found one showing 

 the teeth and craspedodrome nervation of I'. iiohiVix. Tliev all have the 

 distinctlv camptodrome nerves, as shown in Les(jUereux's tigures. I have 

 therefore decided to keep them under Aralia. 



The further (pu^stion of the correctness of this generic reference, or 

 rather of the relation of {[na Aralia notata to the genus Platanus, will not 

 now l)e taken up. Janko has said" that Pkitanas nohiJis "non est Platanus," 

 wdiile on the other hand Professor Ward has suggested'' that several of the 

 so-called species of Aralia uiav have to be tmited into a group, under the 

 name of Protoplatanus, representing tiie ancestors of Plataiuis. A small 

 specimen of this species, obtained 1)v Prof. J. 1'. Iddings from a gulch north- 

 east of the peak west of Dunraven, is exceptionally well preserved, at least 

 as regards the finer nervation. This is very regularly s(piare, bemg only 

 about 0.25 mm. in size. The leaf appears to have been rather thick, possibly 

 coriaceous. 



No other specimen that I have seen has this finer nervation so well 

 preserved. 



Habitat: Fossil Forest Ridge, Yellow^stone National Park, bed No. 

 7, "Castanea bed", about 25 specimens; collected by Lester F. Ward 

 and F. II. Knowlton, August 1(1-20, 1887. Southeast end of hill aliove 

 (north) Lost Creek, bed No. 4, 2 leaves; collected by F. H. Knowlton, 

 Ang'ust 8, 1888. Yellowstone River, one-half mih^ ])elow mouth of Elk 



' Probably Elk Creek on Yello-n-stone River. F. H. K. 



-Abstamrauug d. Pliitauen, Englers bot. .labrb., Vol. XI, 1889, p. 456. 



•Typi'S nf till' Lnraniie Fl., p. 63. 



