470 



ILLUSTRATIONS OK THE NATURAL ORDERS. 



more ovaries, separate or somewhat united, with one or more ovules 

 in each. — Ex. Saururus, Hottuynia : a small group. 



1123 1129 



906. Ord. Ceratophyllaceffi {Homwort Family) consists of the single 

 genus Ceratophyllum (growing in ponds and streams in many parts 

 of the world) ; distinguished by the whorled and dissected leaves 

 with filiform segments ; the flowers monoecious and sessile in the 

 axil of the leaves ; the stamens indefinite, with sessile anthers ; and 

 the simple one-celled ovary, which forms a beaked achenium in fruit, 

 containing an orthotropous suspended seed, with four cotyledons ! 

 and a manifest plumule. 



907. Ord. CallitrichaceSB ( Water-Starwort Family), formed of the 

 genus Callitriche ; aquatic annuals, with opposite entire leaves ; the 

 axillary flowers (either perfect or monojcious) with a two-leaved 



FIG. 1127. Saururus cemuus. 1128. A separate flower, with its bract and a part of the 

 axis magnified. 1129. A more magnified anther, discliarging its pollen from one cell. 1130. 

 Cross-section of the ovary. 1131. Vertical section of one of the carpels in fruit, and of the 

 contained seed, with the sac at the extremity of the albumen, containing the minute embryo. 

 1132. A seed. 1133. Same, with the outer integument (testa) removed, showing the vitellus. 

 1134. The latter, highly magnified. 1135. Section of the same, showing the enclosed heart- 

 shaped embryo. 



