ISOETACEAE. 17 



Family 2. SELAGINELLACEAE Underw. 



1. SELAGINELLA Beauv. 



Stem-leaves all alike, many-ranked. 1. S. rupestris. 



Stem-leaves of 2 kinds; 4-ranked, spreading in 2 planes. 2. S. apus^ 



1. Selaginella rupestris (L.) Spring. M. p. 26. Dry rocks. Summer. 



Philadelphia— Above Manayunk, Mart. (B. C). BwcAs— Nockamixon 

 (Fr.). Chester— (P.). Lancaster— York Furnsice (B.e.) (Ke.). Berks— 

 (P.). NorthamptoJi — 'Easton (P.). 



Hunterdon— MiUord (C). 



New Castle— Bockj Ridge, Point Lookout. 



2. Selaginella apus (L.) Spring. M. p. 27. Low shady places. Summer. 



Family 3. ISOETACEAE Underw. Quillwort Family. 



1. ISOETES L. Quillwort. 



Submerged or rarely emersed in very dry seasons; leaves quadrangular, 

 without peripheral bast-bundles. 

 Stomata wanting; macrospores crested. 1. /. lacustris. 



Stomata present; macrospores echinate. 2. I. echinospora var. 



Amphibious or submerged only in earlier stages; stomata always present on 

 the quadrangular leaves. 

 Peripheral bast-bundles wanting. 3. I. riparia. 



Peripheral bast-bundles present. 



Macrospores sparsely covered with irregular crests. 



4. I. Dodgei. 

 Macrospores with honeycomb-like reticulations. 



5. 7. Engelvianni. 



1. IsoETES LACUSTRIS L. M. p. 27. Ponds. Summer. 



Delaware— Darlo J (B. Sm.). 

 2a. IsOETES ECHINOSPORA Braunii (Durieu) Engelm. M. p. 28. Ponds. 

 Autumn. 



Ocean — Toms River (C). 

 26. IsoETES ECHINOSPORA ROBUSTA Engelm. M. p. 28. Ponds. Autumn. 



Bucls—'Durha.m, Euth (Fr.) 



3. IsoETES RIPARIA Engelm. M. p. 28. Gravelly shores. Summer. 



Fhiladelphia—Torres&ale (Wn.). BmcA's— Andalusia, Mart. (Fr.), Tul- 

 lytown (Fr.). Deto ware— Tinicum (Fu.), banks of the Delaware (B. Sm.). 



Camden— Cooper's Point, Mart. (B. C). GioMcester- Delaware, oppo- 

 site Chester (Le.), Timber Creek (Te.). 



New CasiZe- River shore, B. Soopes, Canhy, Commons. 



4. IsoETES DoDGEi A. A. Eaton. M. p. 29. Mud flats. Summer. 



Buds— Point Pleasant, Dr. Geo. Best (Fr.). 



5. IsoETES Engelmanni a. Br. M. p. 29. Shallow ponds and ditches. 



Autumn. 

 Bucks— 'Sear Perkasie (Fr.), Riegelsville, E. A. Eau (Fr.). Lancaster 

 — Smithville (Ca.). 



Camden — Camden (C). 



New Casi?e— Thompsons, Farnhurst, Ogletown. 



