DESCRIPTION OF SPECIES— RHIZOCARP.E. 65 



Salvinia Allcni, Lesqz. 



Plato V, Fig. 11. 



Ophiogloasum Alleni, Lesqx., Annual Report, 1S72, p. 371. 



Leaves oval, ronnded in narrowing to the base; lateral veins, none visible; areolae large, irregu- 

 larly square or equilateral, inordinately distributed. 



Leaf about three and a half centimeters long, twenty-two millimeters 

 broad, of a thin substance, with a thick middle nerve and irregularly quadrate 

 meshes, formed of very distinct black nervilles, the primary ones more or less 

 in right angle to the middle nerve, with oblique, generally parallel veinlets 

 between them. The borders are black, slightly undulating, as if they 

 were formed by a vein coming out of the attenuated base and following 

 them. By its form, its areolation, its size, all its characters, indeed, it is 

 remarkably similar to Salvinia reticulata, Heer (Fl. Tert. Helv., iii, p. 156, 

 pi. cxlv, fig. 16). It merelj' differs by the surface not smooth or polished, 

 indicating a very thin, pellucid leaf; by the areolation not quite as large, all 

 the meshes in the same direction, rather tending upward than downward ; by 

 the gradually narrowing curve to the base, vvhicli form a regular oval leaf. 

 As in Heer's sjjecies, this one has its areas free, without trace of reticulation. 

 It may represent the same species. 



Habitat. — South Park, near Castello's Ranch {Prof. J. A. Allen). 



Salvinia attciiiiata, Lesqz. 



Plate LXIV, Figs. 14, 14 n. 



Salvinia attenuata, Lesqx., Annual Report, 1874, p. 296. 



Leaves small, opposite, joined by a narrowed, short-pediceled base, broadly oval or round, indis- 

 tinctly reticulated in vertical jiarallel rows of large quadrate cells, marked in the middle by black spots 

 coniposed of very small close cells or pores, without trace of a middle nerve. 



The species is represented by the two small leaves figured here, one, the 

 largest, exactly round, measuring one centimeter both ways, the other, smaller, 

 ovate, only eight millimeters long and five millimeters broad. Tlie leaves, 

 joined at the base, attenuated to a short pedicel, have no trace of a middle 

 nerve or of a separation in the middle, the surface being composed of large 

 areolae exactly square, formed by veinlets ascending from the base and di- 

 verging, and from parallel veinlets crossing them in right angle from the 

 borders. These secondary veins are indistinct, and the surface of the leaves 

 appears, with the glass, like a small checker-board, with the squares marked 

 in the middle by an obscure spot apparently formed of round pores, or like a 

 very small wart. This species is closely related by its areolation and the 

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