From the Proceedings of the American association for the Advancement 
of Science, Vol. XXXI, Montreal Meeting. 
On the Position of the Gamopetae.e. By Lester F. Ward, of 
Washington, I). C. 
In 1789, Lament cle Jussieu, in his “ Genera Plantarum,” estab- 
lished the three “Divisions” of Dicotyledons, assigning the 
Apetalous Division the lowest place, the Monopetalous Division 
the second, or intermediate, place, and the Polypetalous Division 
the highest place in the series. 
In 1848, Adrien de Jussieu, in his “Coins Elementaire de 
[abstract.] 
460 461 
BY LESTER F. WARD. 
Botanique,” reversed the order of the second and third of these 
Divisions and gave his reasons therefor. 
Notwithstanding this, nearly all subsequent authors have 
steadily adhered to the order established by Laurent de Jussieu, 
which is supposed to have been that of his uncle Bernard, the real 
founder of the “ natural system.” 
This arrangement has, however, been severely criticised by Al. 
Braun and many others. 
The present paper is designed to supplement an article “ On the 
Natural Succession of the Dicotyledons” communicated by the 
writer to the “American Naturalist” for November, 1878, and to 
bring forward some evidence from statistics and from palaeontology, 
as that did from organogeny, of the comparative recency of those 
plants having tubular, bell-shaped, or otherwise consolidated cor- 
ollas, and thus to claim for that Division of the Dicotyledons — 
the Monopetahe, or Gamopetalce, as they are now more properly 
called — the highest place in the series, as did the younger Jussieu. 
This is shown, first, by the great extent to which these plants 
are herbaceous as compared with those having the petals free 
(Polypetalce) or with those destitute of petals (Apetalce, or Mono- 
chlamydece). 
From a comparison of seventeen floras, including those of the 
Eastern United States, of California, of Great Britain, of Italy, 
of the AVest Indies, etc., it is found that of the total Dicotyledons 
the Apetalous Division furnishes on an average 13.3 per cent, the 
Polypetalous Division 43.3 percent, and the Gamopetalous Division 
43.4 per cent; but when the shrubs, trees, and woody vines of 
each of these Divisions are alone considered, we find that the 
Apetalw furnish about 24 per cent, the Polypetalce over 43 per 
cent, and the Gamopetalfje only about 33 per cent. In some of 
the floras compared the percentage of this last Division is as low 
as 20. 
A perhaps still more striking way of showing this is to see what 
proportion the woody plants of each Division bear to the total 
number in that Division ; e. g., of the Apetalai, which in the 
flora of the Eastern United States form only 13 per cent of 
the total Dicotyledons, 42 per cent are woody, while of the 
Gamopetalce, which form 47 per cent of the Dicotyledons, only 
1G per cent are woody. 
If trees only are taken into the account the contrast becomes- POSITION OF THE GAMOPETAE7E ; BY E. F. WARD. 
462 
still stronger. In the Inst named flora, which is the largest of 
those compared, the Apetalce constitute 38, the Polypetalce 45, and 
the Gamopetcilce 17 per cent of the dicotyledonous trees. 
These facts seem to show that the Gamopetcilce constitute a 
comparatively late type of vegetable growth which has not yet 
had time, as it were, to perfect itself and assume the frutescent 
and arborescent forms which mark the highest development, or 
phytological maturity. 
In the second place, and in order to anticipate the possible ob- 
jection that this might equally prove degeneracy, such as is seen 
in the Monocotyledons and in the Cryptogams, which, though 
known to be older types of vegetation, are, nevertheless, at the 
present time chiefly herbaceous, although once probably for the 
most part arborescent, the following paheontological evidence was 
adduced : 
It was shown 
1. That the first appearance of plants that are clearly referable 
to Gamopetalous genera is much later than that of either Apetalous 
or Polypetalous plants. 
2. That the most abundant of those genera are such as in the 
living flora have very deeply lobed corollas, as in Viburnum, thus 
approaching the dialypetalous condition and strongly suggesting 
that at the time of their appearance they might not have been 
truly gamopetalous at all. 
3. That the relative paucity of gamopetalous species is much 
more marked in fossil than in living floras. 
4. That the lower the horizon, the greater the disproportion in 
this respect. 
5. That in all collections the number of specimens of fossil is 
less than of living Gamopetalce in proportion to the number of 
species; i. e., there were then not only less numerous forms, but 
those that existed were less abundant. 
These several propositions were supported by copious citations 
and by tubular exhibits compiled from Schimper’s “ Palcontologie 
Vcgetale,” Ileer’s “ Flora tertiaria Helvetia^” Lesquereux’s Creta- 
ceous and Tertiary Floras of the United States, and other works, 
as well as by data obtained from the collections of fossil plants 
at the United States National Museum. 
[Salem 1’kess, July, 1883.]