ML'SEUM OF COMI'AUATIVE ZOOLOGY. 227 



Gencs Liriodcndron. Leaves panduriform, oppositely bilobed ; lobes oblicjue 

 or in right angle, obtuse or acuminate ; midrib thick ; lateral veins in right 

 angle, opposite or irregularly alternate. 



1. L. giyanteum. Leaves large, twenty centimeters broad between the lower 

 broad (six centimeters), oblong, obtuse or rounded lobes ; upper lubes shorter, 

 slightly turned upwards, narrowed and rounded to an obtuse point, joining the 

 lower in an obtuse sinus at a short distance (two centimeters) from the medial 

 nerve. 



This form is the <5ne more distinctly related to Liriodendron tuUpifera, 

 the species living at our epoch. It cannot be considered identical with 

 it, however, the difference in the characters of the leaves being too 

 marked, but not more so than in the following forms, which I consider 

 as new species. 



2. Liriodendron acuminatum, sp. nov. Leaves small, about halt' as large as 

 in the preceding species, cut in two pairs of narrow linear acuminate lobes, 

 about one centimeter broad, all curved upwards. 



3. Liriodendron cruciforme, sp. nov. Leaves large, upper lobes broad, square 

 or equilateral, in right angle to the broad midrib ; lower lobes narrow, linear, 

 acuminate, much longer and turned upwards. The shape of the leaves is like 

 that of an anchor, except that the medial nerve or axis does not pass above the 

 upper borders of the lobes. 



4. Liriodendron semi-alatum, sp. nov. Leaves divided at the base in two 

 oppo.site short rounded lobes (one on each side) curving up to near the medial 

 nerve and then enlarging upwards into an obovate or spathulate entire lamina. 



5. Liriodendron jnnnatijidum, sp. nov. A single leaf with the general facies, 

 and the venation of a Liriodendron, but subalternately trilobate on each side. 

 The top of the leaf is broken. 



Besides the above forms, there have been described already, from the 

 Dakota group, Liriodendron Meekii, Heer, a species with comparatively 

 small leaves, only three to five centimeters long, two to four centimeters 

 broad, the lobes equal in length, short and rounded ; and Liriodendron 

 primeevum, Newb., from a leaf of which the upper half is destroyed, and 

 whose characters are not sufficiently defined. By the size of the leaves, the 

 species is intermediate between L. MeeHi, Heei', and L. intermedium, Lsqx. ; 

 form also known from a single lacerated leaf, which, narrow in the middle, 

 has long obtuse lobes turned upwards, and a facies different from that of 

 any of the other forms described. We have thus eight specific forms of 

 leaves representing the clearly defined type or genus Liriodendron, all dif- 

 fering so greatly that it is not possible to consider them as mere varieties 

 of one species only, and nevertheless of characters so closely allied that 

 their specific identification seems to be hazardous. And this, as said 

 above, is the case with most of the so-called species of the Dakota group. 



