4 PROCEEDINGS OF THE ACADEMY 0? 



them little attention ; nor did he when journeying contemplate a Supplemen 

 to Michaux's Sylva, which was done at the request of Philadelphia publishers 

 after he had ceased his American wanderings. Hence the volumes of Nuttall 

 have neither the freshness and life of description, nor that fidelity to nature in 

 the plates, which are so remarkable in those of Michaux, who travelled for 

 the especial purpose of publishing a work on the trees of America. 



The closet botanist cannot master the botany of trees as well as that of 

 herbaceous plants, because of the latter he often has the whole, but of the 

 tree he can at most possess in his herbarium but a mere fragment, which is 

 far from showing all its important characteristics. He who has made trees 

 his especial study can distinguish the different species even in midwinter, 

 when many of them are destitute of leaves. I make these remarks to show 

 why the two next described species of Fraxinus, which are prevalent both at 

 the North and at the South, have been generally referred to one or the other 

 of the three species before mentioned. 



Fraxinus albicans, S. nov. Foliolis 2 4-jugis sessilibus, ant breviter 

 petiolatis, ovatis, aut ovato-lanceolatis, integris vel serratis, subtus glaucis, 

 tarde utrinque glabris, paniculis laxe terminalibus seu axillaribus ; samaris 

 linearibns 12 18 lin. Ion. emarginatis, basi subteretibus. 



It is found from New England to Texas, being the largest of the American 

 ash trees, sometimes attaining a diameter of between four and five feet. Its 

 bark is furrowed and of a light grey ; hence it is called the white ash in many 

 places. Its petioles are grooved, and its buds are destitute of the red velvety 

 pubescence peculiar toF. americana. I have not seen it in the vicinity 

 of Philadelphia, nor is there any specimen of it collected in this neighborhood 

 in the herbarium of the Academy. In the herbarium of Darlington, at West 

 Chester, I saw specimens of it labelled F. americana, and it is probably 

 thus called by other American botanists. The West Chester collection had 

 no specimens ofF. americana or F, pubescens. 



Both F. americana and F. albicans being called white ash throughout 

 the country have caused them to be confounded, especially where, as is often 

 the case, they do not both grow in the same locality ; but the fruit of the 

 latter is only about half the size of the former, which, with the other distinc- 

 tions enumerated, show that they are very different species. 



Fraxinus oblongocarpa, s. nov. Foliolis 2 4-jugis lanceolatis, vel 

 ovato-lanceolatis, acuminatis, basi cuneatis, integerimis, vel parce serratis, 

 utrinque viridis, junioribus subtus parum pubescentibus, breve petiolatis ; 

 samaris lineari-oblongis, obtusis vel emarginatis, basi subteretibus, et anguste 

 alatis. 



A small tree, thirty or forty feet high, growing along water courses from 

 Pennsylvania to Texas. Its young branches and the footstalks of the leaves 

 covered with a velvety pubescence. Fruit 18 lines to 2 inches in length and 

 2 3 lines wide, the terete part short in proportion and somewhat winged, 

 leaflets 34 inches long. This is the Fraxinus pubescens described in 

 Darlington's Flora Cestrica, but not of Michaux. It differs from F. pu b e s- 

 c e n s in its terete petioles ; its leaves are of a deeper green beneath, and both 

 its leaves and branches are less pubescent when mature. Its samara are 

 longer and nearly one-third less in width, nor are they mucronate, or as sharp 

 pointed as in F. pubescens. 



For those who have not Michaux's Sylva, the following brief descriptions of 

 the white and red ash are given. 



Fraxinus americanus (Linn.) Foliolis 3 4-jugis, breviter petiolatis, 

 ovato-lanceolatis, integerrimis, acutis, subtus glaucis, petiolis teretibus ; gem- 

 mis rnfo-velutinis ; samaris lineari oblongis obtusis vel acutis, basi teretibus, 

 subacutis. 



Fruit 23 inches long, but generally about 2J inches in length and 4 5 

 lines broad in the widest part ; common petiole terete. 



[Jan. 



