158 Lloyd and Underwood : A Review of the 



posed of a single layer of parenchyma cells. All four species store 

 up toward the end of the growing season a large amount of re- 

 serve food, for the most part starch, and as a result of this habit 

 the terminal portions of their horizontal stems become considerably 

 thickened. The stele is also enlarged in these parts, and the 

 air spaces are very much reduced, more so in Z. alopecuroidcs, 

 however, than in the others. - These terminal parts of the stems 

 serve to perpetuate the plants during the winter. There is also 

 not a little difference in the size of the stems, L. pinnatum having 

 the smallest, with L. inundahtm next in order ; L. alopecaroides 

 has the thickest stem of the four. 



8. L. Carolinianum L. Sp. PL 1104. 1753 



Stems short (1— 1 5 cm.), slender (1-1.5 mm - diam.), prostrate, 

 pinnately branching, rooting occasionally from the under side ; 

 leaves strongly dimorphic, the apparently lateral ones large (5-6 

 mm. x 1.5-2 mm.), ovate -lanceolate, falcate, recurved, broadest be- 

 low the middle, with a midrib asymmetrically placed, thin, entire, 

 acute: leaves of the upper side smaller (3-4 mm. x 0.8-1 mm.), 

 subulate with a broad base : leaves of the peduncles reduced to * 

 small (2-3 mm.) subulate more or less appressed bracts : peduncles 

 5-22 cm. long, slender, with few usually whorled or scat- 

 tered bracts : strobiles (1-5 cm. long x 2-2.5 mm.) with sporo- 

 phylls (2x3 mm.), these triangular or somewhat contracted above 

 the base, margin entire or erose : sporangia subglobose. 



Habitat : In wet places, swamps. 



A plant with a very pronounced dorsiventral character, in 

 which the apparently large lateral leaves are really leaves of the 

 under side, giving it a superficial resemblance to a liverwort. Al- 

 though similar in some regards to L. inundatum and L. pinnatum, it 

 is to be separated from them by its above just described dorsi- 

 ventral character. 



Specimens from the United States have been examined as fol- 

 lows : 



* 



New Jersey : Atsion, Aug., 1897, J. A. Allen (G) ; Leed's 

 Point, 1833, A. Gray (G) ; Quaker Bridge (N) ; Toms River, 

 1894, L. H. Lighthipe (?); Egg Harbor, Sept., 1884, L. M. 

 Underwood (U) ; Hospitality Bridge, Aug., 1883, C. A. Gross 

 (strobile 1.5 cm. long) (Y) ; Toms River, July, 1898, \V. N. 

 Clute (Y). 



