FLORA or TIIE ISTHMUS OF PANA5IA. 155 
Dr. Seemaim's plant is intermediate between Scohspermum SaItimoroi(Jes, Lessing, and Baltimora 
recta, LIun., and at first sight all three seem to belong to one species, so much alike is the habit of all. In 
the common B. recta the chaff of the receptacle is blunt, or somewhat acute, but never acuminate ; the im- 
mature aeh^nia, as well of the ray as of the disc florets, having constaatiy a little lunthcd deciduous p:ip- 
pus, which is only crown-like, without any teeth in our species and its variety, and the ripe ucluvula are tri- 
quetrous, but not at all extended into one ovate-winged appendage at the summit of each augle, as in our 
variety. In Scohspcrimm Baltimoroides, Lessing, there are two wing-like appendages at the summit of 
each angle in general, but even in the authentic specimen gathered by Schiedc I observed one of them 
sometimes wanting, so that Dr. Seemaim's plant can only be considered as a mere variety of it, with less 
ciliate chaff of the receptacle. Otherwise I detected no difference, except that Dr. Seemann's plant is a 
more luxuriant one, with the leaves and petioles of greater size (3 inches long, 1^ luch broad), but of the 
same shape and the same scabrous pubescence. On the other hand it is evident that three plants of such a 
resemblance in liabit, cannot be dispersed into two different genera, chiefly since our variety Pammeiuis 
unites them in so natural and remarkable a manner. Therefore I reduce Lessing's Scolospermum to the old 
Linnean Baltimora, so much tlie more, as in both genera, and not in Scohspcnnum alone, the achtenia of the 
ray-florets are enveloped into a foliaceous integument, with which the wing-like appendages are concreted, 
and not with the developed ach^nia, which are quite the same in both. Otherwise it would be necessary- to 
disjoin the allied genus Melampodium in almost as many genera as there are knoT^Ti species. 
582. Melampodium paludomm, H. B. K., Nov. Gen. et Sp. torn. 4. p. 273. no. 3. Panama, 
on road-sides. 
Our plant agrees well with an authentic specimen in the Eoyal Herbarium at Berlin, and with other 
original specimens gathered by Schiede in JNIexico, and defined by Lessing ; but in the fertile acha^nia the 
transversal line in the lateral surface is entirely wanting or obsolete ; the younger oucs being smoother than 
the ripe achjcnia, w^hich are " subverrucoso-exasperata." Lessing, and after hun De Candolle in Prodr. torn. 5. 
p. 520, imite this species with Melampodium divaricatum, De Cand. ; it seems to me however to be distm- 
guished by its slender and simple habit. Melampodium dimricatum is a stouter plant, with a much thicker 
stem, branching often from the base, and with firmer leaves. 
583. AcANTHOsPERMrM humile, Dc Cand. Prodr. torn. 5. p. 522. no. Z.— Melampodium humile, 
Swartz Prodr. Fl. Ind. Occ. —Centrospermum Immile, Lessing in Synops. Pananaa, in waste places. 
Varies with the leaves at the base cuneate and entire, or lyrato- dentate. 
584. Wedelia carnosa, Rich., De Cand. Prodr. torn. 5. p. 538. no. 1. 
Yar. foliis late ovatis acutis inaqualiter et remote serratis, supra scabris subtus glabris. On the 
sea-sliore of the Pacific Ocean. 
The leaves of this species are most variable in size and shape. In our specimens they are broadly 
ovate acute, cuneate and narrowed at the base, but truly sessile, serrate, with sharp, remote, and miequal 
teeth' of which the lowermost is the largest, showing thus a tendency to become trilobate. They are 
fleshy 3-4 inches long, l-lf mch broad, rough above, with few strigose, appressed hairs, and smooth and 
glabrous beneath ; the peduncles and foliaceous oblong entire scales of the involucre are also beset with 
white appressed strigose hairs. Acha^nia not ripened. 
585. AViiuELiA Caracasana, De Cand. Prodr. torn. 5. p. 541. no. 19. Chiriqui Volcano, 
Veragnas. 
Dr. Seemann's specimens entirely agree with those gathered by Otto at La Guayra. 
586 Wedelia acuminata, De Cand. Prodr. torn. 5. p. 541. no. 20. Panama, in savanas. 
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