272 BOTANY. 



XEROTIDEJE. 



Dasylirion* GKAMiNiFOLiuMjt Zucc. — Caudex 4° high; scape 8-10° 

 high, 2' in diameter; leaves 2° long, 6-10" wide, spiny serrated; spikes of 

 the flowering panicle subtended by lanceolate, clasping bracts; perianth 

 white or whitish; filaments much exceeding the lobes; embryo cylindrical, 

 in the centre of a hard, horny albumen and nearly as long ; fruit whitish, 

 with a purple tinge, conspicuously 3-winged. — Southern Arizona (329, 655). 



Dasylirium erumpens, Ton*. — Caudex and scape 6° high; leaves 

 linear, 2-3° long, 4-6" wide at base, and regularly tapering to the tip, semi- 

 terete below, channelled above, edges rough; fruit 3-lobed, 3-celled, and 

 not winged (but appearing so from the diverging cells), broader than long, 

 thin, membranous, and burst by the maturing seed ; the sheathing bract at 

 base of each primary branch attenuate into a long filiform tip. — Rocky 

 Canon, Arizona (278). 



This my friend Mr. Watson has named Lindheimerianum, but it cor- 

 responds so well in its fruit and leaves that I have named it as above. 



junce^:. 



By Dr. George Engelmann. 



Juncus Balticus, Deth., y. montanus, Engelm. Revis. June, in Trans. 

 Acad. Saint Louis, 2, 442. — A smaller inland form of this species, with 

 nearly equal segments of the perigon, longer, beaked capsule, and slender, 

 pointed seeds. — Colorado; New Mexico to Nevada; Rothrock (23). 



Juncus triglumis, Linn — Ctespitose, with short subulate leaves, chan- 

 nelled near the base; naked stems 3-5' high, bearing a terminal head of 2 

 or 3 flowers, enclosed in large broad bracts ; obtusish sepals shorter than 

 the oblong, obtuse, mucronate capsule ; filaments many times longer than 

 the small anthers; large seeds loosely enveloped in the striated coat, appen- 



* Dasylirion, Zucc. — Fl .wers dioecious. Male-flowers 2-3 iu clutters, enclosed iu thiD, hyaline, 

 somewhat fimbriate bracts; pedicels 1-2" loug, jointed above; perianth of similar white or whitish 

 divisions; filaments attached to the base of the divisions; pistil abortive. Female flowers iu bracteate 

 clusters, like the males; ovary sometimes 1-, sometimes 3-celled, with usually 0" ovules, of which but one 

 or two mature into seeds. — Erect, hard herbs, with clusttrs of narrow, recurved leaves crowuing the 

 caudex. Scape 0-14° high, terminated by large masses of small flowers. The ends of the leaves usually 

 split up into white, thin, strong fibres, which could doubtless be utilized iu the manufacture of cordage. 



t Dasylirion graminifolium, Zucc. Since the above was put in type, Mr. Watson has determined this 

 plant to be a new and clearly distinct species, which he names I). Wheclcri. See note under Table of 

 Orders, at. end of volume. 



