Excerpt a Botanica. 



261 



andri. Filamenta filiformia. Antherce biloculares, loculissub- 

 globosis, apice contiguis, basi remotissimis, bilocellatis, rima 

 longitudinali laterali dehiscent ibus. Pollen globosum, murica- 

 tum, rima unica (?) donatum. Fcem.l. Ovarium uniloculars 

 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. Embryo in axi albuminis carnosi rectus, mono- 

 cotyledoneus, gemmula seorsim (radiculam) spectans in rima 

 laterali, radicula supera, infera vel vaga*. 



f Vasa spiralia transitoria, vel nulla. Planice novella nudce. 



A. Frondes rima una basilar! hiantes. Flares in pagina frondis superiore 



erumpentes. 



I. Wolffia, Horkel MSS. (Horkelia, Reich, non Schlechtend.) 



Flos masculus unicus. Filamentum breve, crassiusculum. Flosfcemi- 

 neus unicus. Ovarium uniloculare, uniovulatum, ovulo uno 

 recto, anatropo ; stylus brevis ; fructus utriculus monospermus ; 

 semen erectum ; embryo turbinatus ; radicula supera. 



1. W. Delilii. Frondes ovales, tenuissimse, geminatim oppositse, 

 arrhizse ; labium inferius rimee basilaris productum, appensum, 

 hyalinum. Lemna hyalina, Del. Lemna e Rosetta, Herb. Willd. 

 no. 17144. L. 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 rinds binis basilaribus Mantes. Flores e rima later aliter pro- 

 deuntes. 



II. Lemna. 



Flores masculi, altero in evolutione prsecociori. Filamenta filiformia, 

 recurva ; ovarium uniloculare, uniovulatum, ovulo erecto, hori- 

 zontal!, hemianatropo ; stylus elongatus, recurvus ; fructus 

 utriculus monospermus indehiscens ; semen in fundo affixum , 

 horizontale ; embryo conicus ; radicula vaga. 



1. L. minor, Linn. Frondes obovato-subrotundae, crassiusculse, 

 ternatim quaternatimque, rarius plures cohserentes, monorrhizae ; 

 stipite frondis novelise 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 ' ig 

 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. 



