Lyon - OBSERVATIONS ON EMBRYOGENY OF NELUMBO. 645 
the embryo-sac, Trecul (’54, 2) a concretion of a homogeneous 
substance containing numerous small, acicular crystals, and 
finally Wigand-Dennert (’87) in a monograph on Velwmbium 
speciosum wrote: ** Es ist unzweifelhaft der Ueberrest von Endo- 
spermzellen, welche sich in der Héhlung zwischen den Cotyle- 
donen erhalten und gleichsam auf der Oberflache der Plumula 
niedergeschlagen und dadurch das Ansehen einer Membran 
erhalten haben.” 
From the above survey of literature it will be seen that mod- 
ern knowledge of the seed is based on investigations made upon 
mature or nearly mature fruits. That alone which will deter- 
mine the correct interpretation of the structures (7. e., a knowl- 
edge of their origin) is entirely wanting. It was in recognition 
of this fact that the present embryological study was undertaken. 
In a preliminary note, published in Sczence, the more important 
conclusions were announced. 1. The embryo of Velumbo is 
genuinely monocotyledonous in its development. The plumule 
arises laterally and at first there is but one cotyledon which later 
bifurcates to form the two fleshy bodies. 2. The membrane 
surrounding the plumule is, as conjectured by Wigand, a true 
endosperm arising within the embryo-sac. 
COLLECTION AND METHODs. 
The material for the investigation in hand was collected by 
the author in August, 1899, and August, 1900, in southeastern 
Minnesota while working on the botanical survey of that region. 
There, Velumbo lutea grows in great luxuriance in the sloughs 
and bayous of the Mississippi river, the soft muddy bottoms 
and quiet waters of these bayous affording an ideal habitat for 
the plant, where it often forms beds many acres in extent to the 
exclusion of other vegetation. 
In collecting, each carpel was removed from the torus, the 
lower end cut away and the upper portion with the attached 
ovule placed in the fixing fluid. One-half and one per cent. 
chromic acid and chrom-acetic acid were used as killing re- 
agents. The material was thoroughly washed and passed gradu- 
ally into 70 per cent. alcohol in which condition it was brought 
into the laboratory. The ovules were imbedded in paraffine and 
serial sections cut with a Minot microtome. The sections were 
stained on the slide, a variety of stains being used; the photo- 
micrographs and drawings, however, which accompany the 
