270 coNTKiBUTioisrs FKOM THE :n^ational herbakium. 



4. Equisetum kansanuin J. H. Schaffner. Found only at the foot of Sherburne 

 Lake, along a small gully in aspen woods. Mont, to Utah and Mo.— yStems 30 to 50 

 cm. high, rough, with a large central cavity; cones 1 to 2.5 cm. long. 



5. Equisetum fluviatile L. Frequent at low and middle altitudes, in marshes, 

 bogs, or swamps; in sphagnum bog at Fish Lake. Alaska to Wash., Wyo., N. Y., 

 and Newf.; also in Eur. and Asia. — Stems smooth, bright green, the central cavity 

 very large. 



The stems are weak and sometimes procumbent. In the marshes along Swift- 

 current Creek below Lake McDermott this species is very abundant, growing in 

 shallow water and forming dense pure stands, which at a short distance are strikingly 

 suggestive of the similar colonies of Scirpus occidenialis found about the east entrance. 



6. Equisetum palustre L. Apparently rare; a few plants at Bel ton, in sand along 

 the river. Alaska to Oreg., Wyo., Conn., and Newf.; also in Eur. and Asia. — 

 Stems slender, 20 to 40 cm. high, bright green, much branched, deeply grooved, 

 the branches slender, simple. 



7. Equisetum litorale Kuehlwein, Occasional at low altitudes, in wet ground or 

 swampy thickets. B. C. to Pa. and N. B.; also in Eur. — Stems erect or decumbent, 

 20 to 40 cm. high, much branched, deeply grooved; sheaths with dark brown teeth; 

 branches 3 to 5-angled. 



This form is now believed to be a hybrid between E. fluviatile and E. arvense. 

 Some of the material referred here may consist of sterile shoots of E. arvense with 

 abortive cones. 



8. Equisetum arvense L. Common and often abundant, at all altitudes except 

 the highest; in wet meadows or thickets or along streams or lake shores; frequent on 

 rocky slopes or in wet gravelly soil above timber line. Widely distributed in N. Amer. , 

 Eur., and Asia. — Sterile stems 10 to 30 cm. high, much branched, bright green, 

 6 to 20-grooved, deeply furrowed; sheaths of the fertile stems with about 12 teeth. 



The fertUe stems develop in early spring. In late summer the buds that produce 

 them may be found about the bases of the sterile stems. Some of the plants above 

 timber line, especially near snow banks, are nearly prostrate and are very sparsely 

 branched. This species is common about the east entrance, extending out upon the 

 prairie. It thrives particularly well upon railroad embankments, where dense 

 patches grow from dry gravel and cinders. 



9. Equisetum sylvaticum L. Rare on the east slope and found only in a boggy 

 place in woods at the edge of Lake Josephine; occasional on the west slope at middle 

 altitudes, in boggy places in woods. Alaska to B. C, Va., and Newf.; also in Eur. 

 and Asia. — Stems 10 to 40 cm. high, 8 to 14-ridged, 3 to 4 mm. thick, the branches 

 compound and feathery, bright green; cones long-stalked. 



This is very different in appearance from our other species, and it is the only one 

 which is at all attractive in appearance. The plants often form dense tangled masses. 



4. LYCOPODIACEAE. Clubmoss Family. 



1. LYCOPODIUM L. Clubmoss, 



Low plants with leafy, simple or branched stems; leaves small, resembling those 

 of cedar or juniper; spores in sporangia, or spore cases, these borne in the axils of 

 ordinary leaves or in yellowish club-shaped spikes of reduced leaves. 



Sporangia borne in the axils of ordinary leaves. Leaves rather closely appressed. 



1. L. selago. 

 Sporangia borne in club-shaped spikes composed of much reduced leaves. 

 Fruit spikes not stalked. 

 Leaves arranged in 4 rows on the branches, bluish green, closely appressed. 



2. L. alpinum. 



