43 
- gontal, as’in L. minor ; and, in the 10 or 12 flowers now examined, 
always’ single ; spiral vessels in funiculus, which only occurs. again 
in L. gibba, in this family; exostome, almost closed, while in all 
others it is open or even (in L. paucicostata and perpusilla,) in- 
complete, the endostome strongly protruding.—Seed horizontal and 
slightly compressed, the dark spot of the chalaza distinctly visible, 
even through the utricle, and, as in all 1-ovuled species of Lemna, 
directed backward to the base of the frond; raphe distinct, no 
spiral vessels observed in it; seed (apparently—the specimens ex- 
amined were not completely matured—) smooth as in Wolffia, not 
ribbed as in Lemna; cellular spongy testa very thick; operculum 
distinct ; endopleura, as usual in Lemna, dark brown, thin; endo- 
sperm, (albumen,) considerable.—Embryo, cylindric almost as long 
as the seed, as usual in the family, [what Austin calls albumen “ a, 
his “s” is the starchy albumen,what he calls embryo, is the plumule. } 
I take it to be a one ovuled small form of S. polyrrhiza. : 
In all the specimens éxamined, I find the singular cireumstance 
of the first (anterior) stamen only being developed and protrud-?e TL, /°- 
ing, (but never as far as in other species,) and the second or pos- 
terior one and the pistil being enclosed. Is this owing to the hour 
of the day when collected? It would be worth while to find out, 
whether in Lemna the first stamen may be developed in the 
Morning, and the second at noon or in the afternoon. 
Yours truly, G. ENGEiMAnn. 
86. Imitation.—Darwin, Wallace, and others, have pointed out nu- 
merous cases of imitation in nature for purposes of protection. An 
instance of imitation for offence recently fell under my observation. 
My attention was attracted by a wasp suspended from a panicle of 
Solidago. I at first supposed that the flower had in some way 
entrapped him, but, on closer inspection, found that he was in the 
fangs of a yellow spider of precisely the color of the blossoms. 
87,. The Club—meets at the Herbarium in Columbia College, 49th 
Street, the last Tuesday in every month. Botanists are invited to 
* 
ber Oe ¢ 
Werp, Belgium; Phenogams.—S. B. Mead, sp ie 85 York, We — 
plants in Gray, particularly for the novelties about Repel 
have a list of his desiderata, which we shall be 
of the Club desiring it. 
of > ‘ized a B00 
the region covered by Gray’s Manual, pois? that, “ Leucanthe- 
tions of every state 
; east Ee ee - Wisco . tt has emi- 
grata tg Missin, ence oard tates. found it four miles 
