Vol. 1. No, 8. } BULLETIN OF THE TORREY BOTANICAL CLUB. [New York, August, 1870. 
63. Lemna.— Between Huguenot station and Annadale on the 
Staten Island R. R., branching from a road running nearly parallel 
with the rail road, is another road leading to the shore. A brook * 
crosses this, and among the bushes on the left hand side Epigwa 
grows finely: crossing the fence; beyond the brook, and following 
a path obliquely towards the shore, rather more than a quarter of 
a mile into the woods, we find two little hollows filled with water. 
About the end of July, I found these covered with the Lemna men- 
tioned in the following note from Dr. Torrey. Since receiving it, 
I have been able to see the palmate veins, very distinctly in the 
decayed leaves. The fronds vary much in size, those with mature 
fruit I have always found quite small, but have seen the stamens 
on some nearly or quite as large as the ordinary S. polyrrhiza. 
Even in July, the plants were producing what Hegelmaier calls the 
winter fronds together with the usual kind. I have sent good spe- 
cimens to him. Excursions made to procure more specimens were 
successively less productive; I presume, therefore, that the flowers — 
Were most abundant early in July: LZ. perpusilla, Torr., which is in- 
termingled with it, is beginning to blossom at the end of August. 
= L. umbonata, A. Braun, is referred by Hegelmaier - 8. oo 
iza. : : 
Thave made a careful study of the Lemna that you brought me 
from Staten Island. It is clearly a-Spirodela, if that genus be 
adopted, but, whether a mere variety of L. ( Spirodela) polyrrhiza or 
a distinct species, I am in doubt. In all the fertile flowers that I 
examined, there was but a single ovule in each ovary. Two of the 
fronds bore ripe fruit, each with a single seed. The fronds are 
Smaller than in the ordinary state of L. polyrrhiza, seldom more 
than 24 lines long, and-I found no traces of palmate nerves. 5 ee 
Five or six years ago I received living specimens ofa Lemna,in 
flower and fruit, collected by Mrs. Brown, of Brattleboro, Vermont, == 
and named, L. polyrrhiza, I have preserved no notes respecting _ 
© ovary, and the specimens reserved for my herbarium have 
n too much injured to permit a reexaminatiom of them. It is 
+ doubtful, therefore, whether the plant is similar+to yours, or a 
genuine L. polyrrhiza, with binovulate ovaria. a 
Many years ago, (1845,) I received from Dr. Engelmann a Lemna ae 
found by him near St. Louis, and named “ L. umbonata, A. Byaun — 
tn litt.” Tt was without flowers or fruit. I can/not find any cha- — 
_ Tacter in which it differs from L. polyrrhiza; and Mr. C. F. Austin, — 
Who made a special study of North American Lemnacew, thinks it = 
Snot distinct from that species. You have been very fortunate in _ 
detecting the flowers and fruit of a plant that is so very rarely seen 
MM such condition, notwithstanding it is abundant in almost every 
Part of the world. J. T., Columbia College, Aug. 11th, 1870. 
_ 4, Additional observations on the flora of Lookout Mt—Along the per-— 
Pendicular cliffs are numerous shelves worn horizontally, | usually a 
Tom veins of conglomerate,) often quite deep: in a ae 
*mingly beyond the reach of sunlight or rain, in the dry dust, we 
