. musc i. 49 



13. Hypnum decurrens, Sulliv. (Tab. 10.) 



H. dioicum, majusculum ; caulibus prostratis subcomplanatis parce pin- 

 natim ramosis ; foliis subfalcatis cordato-lanceolaiis tenuiter acuminatis 

 decurrentibus toto ambltu serratis brevissime bicostatatis, celhdis tenuis- 

 simis linearibus alaribus magnis subquadratis ; capsula cernua gibboso- 

 oblonga; pedicello erecto-flexuoso. 



Hypnum decurrens, Sulliv. in Proceed. Amer. Acad. Art. Sci. (Jan. 1854.) 



Hab. Kaala Mountains, Oahu, Sandwich Islands. 



Probably dioicous ; a large species growing in loose shining yellow- 

 ish mats. Stems prostrate, mostly simple, 4-5 inches long and about 

 one line broad, somewhat compressed, pinnated with distant branches 

 of unequal lengths. Leaves loosely imbricating from a broad, cordate, 

 auriculate, decurrent base, lanceolate-attenuate, serrulate, secund, sub- 

 falcate, subecostate, of a firm and thin texture composed of minute and 

 linear cellules ; those at the basal angles large, pellucid, and subquad- 

 rate. Perichsetia numerous : the exterior leaves ovate oblong acumi- 

 nate ; the interior oblong, terminating in a long fiexuous, denticulate, 

 strap-shaped point; all destitute of a costa. Archegonia 35-40, copi- 

 ously paraphysated. Pedicels (two only seen, and they grew from the 

 same perichsetium) erect, fiexuous, smooth, rather short in proportion 

 to the size of the plant. Capsule horizontal, short, hypnoid. 



, This species strongly resembles the North American Hypnum curvi- 

 foUu?n, Hedw., but the latter species has larger perichsetia with whitish 

 striated leaves, and a capsule when dry conspicuously sulcate. 



Plate 10, B. — Hypnum decurrens : plant, of the natural size. 

 Fig. 1. Portion of stem, with leaves. 2, 3, 4, 5, 6. Leaves. 7, 8, 9. 

 Portions of a leaf, showing the reticulation. 10. Capsule. 11. Arche- 

 gonium and paraphysis. 12. Perichastium. 13, 14, 15. Perichsetial 

 leaves. — Details enlarged. 



13 



