428 



SALVINIAOEAE. 



smaller globose pedieelled microsporanges with very numerous microspores. 

 Leaves green, finely papillose on the upper surface. [Name in honor of An- 

 tonio Maria Salvini, 1633-1729, Italian scientist.] About 33 species of wide 

 distribution. Type species: Salvima natans (L.) Hoffm. 



1. Salvinia Olfersiana 



Klotzch. OLFERS ' SALVINIA. (Fig. 

 468.) Completely covering the 

 surface of still water, the floating 

 leaves more or less overlapping, 

 the slender stems 2' long or more, 

 pilose. Floating leaves broadly 

 ovate, 6"-10" long, short-petioled, 

 cordate at the base, obtuse or 

 notched at the apex, pinnately 

 delicately many-veined, the upper 

 surface bearing many short 4- 

 horned or 5-horned papillae ; sub- 

 merged leaves short-petioled, sev- 

 eral-parted, root-like, li'-3' long, 

 bearing the clustered globose- 

 ovoid sporocarps. 



Common in ditches in Pembroke 

 Marsh. Naturalized ; apparently of 

 recent introduction. First observed 

 by us in 1005. Native of tropical 

 continental America. H. B. Small, 

 erroneously designating this plant 

 Lemna trisulca, states that it was 

 introduced in 1003. 



Order 3. LYCOPODIALES. 



Spores produced in sporanges, which are borne in the axils of scale- 

 like or elongated leaves. 



Spores all alike. Fam. 1. PSILOTACEAE. 



Spores of two kinds. Fam. 2. SELAGINELLACEAE. 



Family 1. PSILOTACEAE Pritzel. 

 PSILOTUM FAMILY. 



Perennial slender terrestrial or epiphytic plants. Sporanges sessile 

 in the axils of the leaves, 2-3-celled, opening by valves at the apex. 

 Spores uniform. 



1. PSLLOTTJM E. Br. 



Terrestrial or sometimes epiphytic, the stem dichotomously forked. Leaves 

 alternate, reduced to scales. Sporanges 3-celled, opening by 3 valves at the 

 apex. Spores mealy, oval or elongated-reniform. [Greek, referring to the 

 nearly naked stems and branches.] A few species of tropical and subtropical 

 distribution, the following typical. 



