Excerpta Botanica. 261 
andri. Filamenta filiformia. Anthere biloculares, loculis sub- 
globosis, apice contiguis, basi remotissimis, bilocellatis, rima 
longitudinali laterali dehiscentibus. Pollen globosum, murica- 
tum, rima unica(?) donatum. Fam. 1. Ovarium uniloculare, 
uni- multi- (septem- in L. gibba) ovulatum. Ovulum anatro- 
pum vel hemianatropum vel atropum, in tegumentis binis. Sty- 
lus continuus ; stigma expanso-infundibuliforme. Fructus : utri- 
culus mono-polyspermus, indehiscens vel capsula circumscissa. 
Semen in tegumentis binis, externo coriaceo-carnoso, interno 
membranaceo ; endostomio indurato (operculo) in germinatione 
embryostega. Hmbryo in axi albuminis carnosi rectus, mono- 
cotyledoneus, gemmula seorsim (radiculam) spectans in rima 
laterali, radicula supera, infera vel vaga*. 
+ Vasa spiralia transitoria, vel nulla. Plante novelle nude. 
A. Frondes rima una basilari hiantes. Flores in pagina frondis superiore 
erumpentes. 
I. Wourrra, Horkel MSS. (Horkelia, Reich. non Schlechtend.) 
Flos masculus unicus. Filamentum breve, crassiusculum. Flos feemi- 
meus unicus. Ovarium uniloculare, uniovulatum, ovulo uno 
recto, anatropo ; stylus brevis; fructus utriculus monospermus ; 
semen erectum ; embryo turbinatus ; radicula supera. 
1. W. Delilii, Frondes ovales, tenuissime, geminatim opposite, 
arrhize ; labium inferius rime basilaris productum, appensum, 
hyalinum. Lemna hyalina, Del. Lemna e Rosetta, Herb. Willd. 
no. 17144. JL. arhiza, Herb. Willd. 17141. 
The author is indebted to Dr. Ehrenberg for specimens of Wolffia 
in flower brought from Egypt ; and he detected in Willdenow’s her- 
barium specimens of the same plant in fruit, under the name of 
Lemna, from Rosetta. 
B. Frondes rimis binis basilaribus hiantes. Flores e rima lateraliter pro- 
deuntes. 
II. Lemna. 
Flores masculi, altero in evolutione preecociori. Filamenta filiformia, 
- recurva; ovarium uniloculare, uniovulatum, ovulo erecto, hori- 
zontali, hemianatropo; stylus elongatus, recurvus; fructus 
utriculus monospermus indehiscens; semen in fundo affixum , 
horizontale ; embryo conicus; radicula vaga. 
1. L. minor, Linn. Frondes obovato-subrotunde, crassiuscule, 
ternatim quaternatimque, rarius plures coherentes, monorrhize ; 
stipite frondis novelle discreto fragili. L. cyclostasa, Ell. L. 
minuta, Kunth. L. minima, Chev. L. conjugata, Willd. Herb. 
17143. 
* Brongniart’s description of the embryo in ‘ Archives de Botanique’ is 
very far from being accordant with nature, nor can I possibly imagine what 
could lead him -to the supposition of a canal pervading the upper portion of 
the embryo and nourishing a cordate plumule at its base. 
