American Species of Marchantia. 297 



later description and figure published by Dillenius.*** Plumier's 

 figure represents certain reproductive parts in detail and a 

 thallus with a sinuate or vaguely lobed margin, branching occa- 

 sionally by forking and apparently also by ventral outgrowths. 

 From the tips of some of the branches the four-lobed receptacles 

 on short stalks take their origin and clearly bring the growth 

 of the branches to an end. In two cases — possibly in three— five- 

 lobed receptacles are shown. In his text Plumier compares the 

 appearance of the plant with that of the Indian fig and says that 

 the upper surface is of a pale green color and roughened by 

 minute elevated points. He compares the entire receptacle with 

 a mushroom and states that one side of the disc is rounded, 

 while the other shows four semicircular lobes, the whole resem- 

 bling an inverted goose foot. He adds that each lobe opens 

 longitudinally, and shows minute white "flowers'* in the form 

 of tubes. Each tube divides at the apex after a while into 

 four parts which roll back and disclose an oval fruit filled with 

 "seeds" like fliour. It is clear from this account that he had 

 female receptacles before him and that he saw the involucre, 

 the pseudoperianth, the capsule, and the spores. 



Dillenius took his figure directly from Plumier and did not 

 know the plant itself. He tried to improve the figure, however, 

 by indicating that the upper surface of the thallus was covered 

 over with minute polygons as in related species. Lindberg*^ 

 criticises the figure of Dillenius (and consequently that of 

 Plumier) by stating that an autoicous inflorescence is shown, 

 both male and female receptacles being represented on the 

 thallus. This criticism is undeserved. The receptacles shown 

 are all female, the dorsal surface being represented in some 

 cases and the ventral in others. In his text Dillenius brought 

 out the fact that the receptacles were all the same kind, although 

 he incorrectly interpreted the fruit of Plumier as an anther and 

 the flour-like seeds as pollen, a well-known error which he 

 repeats in his interpretation of the reproductive parts in other 

 bryophytes. 



On the basis of Plumier's description and figures it becomes 

 evident that the term "calyx" in the Linnaean diagnosis of M. 



*°Hist. Muse. 531. pi. 75, f. 5. Oxford, 1741. 



*" Krit. Gransk. Dillen. Hist. Muse. 45- Helsingfors, 1883. 



Trans. Conn. Acad., Vol. XXI 20 1917 



