Observations on the Genus Spathium. 533 



ovoid, and not influenced in the same manner by the iodine 

 solution or acid. 



From the description of Aponogeton pusillum in Rox- 

 burgh's Fl. Ind. and the section of the fruit of A. echina- 

 tum, in his Cor. Plants, t. 81, I should judge that they 

 would have the same characteristics as the A. undulatum. 

 They may perhaps be found to be intermediate, in which 

 case the two species I have examined may be fairly consi- 

 dered as the extremes of a single genus. From the gene- 

 ral habit, and the position of the bracts of Endlicher resem- 

 bling that of half a floral envelope, for which reason I term 

 them sepals in the description, the place of this genus 

 would appear to be next to Potamogeton among the Naiades. 



I have subjoined an amended generic character, and 

 fuller descriptions of the two species I have examined. 



Spathium, Loureiro. — Endlich. Gen. No. 1826, p. 267. 



Flores hermaphroditi, in spadice cylindraceo pedunculato 

 spatha mophylla caduca cincto spiraliter dispositi, sessiles. 

 Sepala duo, petaloidea, sub-opposita. Stamina sex, hypogyna ; 

 filamenta, libera, subulata, patentia, persistentia ; antherae 

 biloculares, lateraliter dehiscentes. Ovaria tria (vel. 4?) 

 rostris erectis; stigma apicale, minutum, obliquum; ovula 

 2-6, basi affixa, ascendentia. Folliculi 3 (4?) introrsum de- 

 hiscentes, 1-3 spermi; semina erecta ovata, testa duplici, 

 exteriore herbacea, interiore membrancea, vel evanida. Em- 

 bryo exalbuminosus, macropodus, erectus, ascendens, ana- 

 tropus, cotyledone magna, varia, plumula varia. 



S. monostachyon, foliis petiolatis lineari-oblongis basi 

 subcordatis emersis herbaceis, floribus in spadice dense con- 

 fertis, sepalis persistentibus. 



Descr. Rhizoma tuberosum, radicibus crassis filamento- 

 sis. Folia petiolata ; petioli subtrigoni, basi membranacei inte- 

 riora amplectentes ; lamina linearis, obliqua, obtusa, basi sub- 

 cordata, vel junior cuneata, 5 venia, venis transversalibus. 



