1054 ISOETACEAE 



3. I. Bolanderi Engelm. Leaves erect, soft, bright green, tapering to a fine 

 point, 5-10 cm. long, thin-walled; stomata few; ligule triangular; velum narrow; 

 sporangia unspotted; macrospores 0.3-0.45 mm. thick; microstores deep brown, 

 spinulose. In water and mud: Wash. Wyo. Colo. Calif. Plain Mont. 

 Au-S. 



4. I. Howellii Engelm. Leaves 5-20 cm. long; stomata numerous; bast- 

 bundles 4; velum narrow, densely spotted; ligule short triangular to 4 mm. long; 

 macrospores 0.48 mm., with low blunt crests; microspores light brown, with low 

 tubercles or spines. /. nuda Engelm. I. Underwoodii Renders. Borders of 

 ponds: B.C. Mont. Ida. Calif. Plain Submont. Je-Au. 



5. I. Nuttallii A. Br. Trunk almost globose, 3-lobed; leaves slender, bright 

 green, 7-20 cm. long; stomata many; bast-bundles 3; velum broad, covering the 

 sporangia; macrospores 0.25-0.5 mm.; microspores brown, papillose. /. opaca 

 Nutt. /. Suksdorfii Baker. Mud: B.C. Ida. Calif. Son. Plain. Mr-Jl. 



FAMILY 7. LYCOPODIACEAE. CLUB-MOSS FAMILY. 



Low, erect or trailing plants, somewhat resembling mosses, with leafy, 

 usually branched, often elongate stems. Leaves small, lanceolate or subu- 

 late or sometimes oblong or roundish, some bearing on their axils or on their 

 upper surfaces solitary 1-3-celled sporanges. Spores minute, of one kind. 



1. LYCOPODIUM L. CLUB-MOSS, GROUND PINE. 



Perennial plants, with evergreen, usually stiff, commonly imbricate, one- 

 nerved, 4-16-ranked leaves. Main stems usually creeping, with aerial branches. 

 Sporangia flattened, coriaceous, usually reniform, 1-celled, opening by a transverse 

 slit around the margin, borne in the axils of ordinary or modified and bract-like 

 leaves. Spores sulphur-colored. 



Sporanges borne in the axils of ordinary leaves, which are not arranged in distinct spikes. 

 Leaves hollow at base, all or mostly all ascending, of nearly one length. 



1. L. Sclago. 

 Leaves flattened, not hollow at base, spreading or deflexed, longer and shorter in 



alternating zones. 2. L. porophilum. 



Sporanges borne in the axils of bracts arranged in spikes on the aerial branches. 

 Spikes sessile, or with stalks not more than 1 cm. long. 



Aerial branches all simple. 3. L. inundatum. 



Aerial branches, at least in part, branched. 



Leaves of the ultimate divisions of the aerial branches in 4 rows. 



4. L. alpinum. 



Leaves of the ultimate divisions of the aerial branches in more than 4 rows. 

 Aerial branches tree-like. 5. L. obscurum. 



Aerial branches not tree-like, mostly loosely forking or forming compact 



tufts. 

 Leaves of the ultimate divisions of the aerial branches in 5 rows. 



6. L. sitchense. 

 Leaves of the ultimate divisions of the aerial branches in 8 rows. 



7. L. annotinum. 

 Spikes borne on bracteate peduncles more than 2 cm. long. 



Leaves of the divisions of the aerial branches in 4 rows. 8. L. complanatum. 



Leaves of the divisions of the aerial branches in many rows. 9. L. clavatum. 



1. L. Selago L. Main stems very short, dichotomously branching into 

 upcurved or erect forking branches forming a tuft 2.5-24 cm. high; leaves crowded, 

 appressed or ascending or rarely a few reflexed, triangular to linear-acuminate 

 or aciculate, acute, entire; sporophylls shorter than the leaves, triangular; plant 

 often bearing gemmae. Rocks: Greenl. Newf. Me. N.Y. Ont. Alaska 

 Mont. Wash. Va.N.C.Tenn.; Mex.; Eu. 



2. L. porophilum Lloyd & Underw. Main stems short, upcurved, dichoto- 

 mously branching into upcurved or erect forking branches forming a tuft 3-35 

 cm. high; leaves crowded, spreading or reflexed, linear or nearly so, entire or 

 rarely very minutely denticulate, those in the zones of the longer slightly broad- 

 ened above the middle and similarly contracted toward the base, those in the 

 zones of the shorter broadest at the base, but very gradually tapering; sporo- 

 phylls entire or minutely denticulate above the middle, acuminate; plant often 



