ROBINSON: CONTRIBUTIONS FROM GRAY HERBARIUM. 263 
which the description clearly applies. The other plant I would 
separate as follows : — 
P. (§ Avicularia) striatulum, spec. nov. Perenne gracile 3-7 
dm. altum glaberrimum, caule tereti glaucescenti striato plus minusve 
flexuoso nodoso infra delapsu foliorum nudo, ocreis striatis 5-7 mm. 
longis, limbo profunde in libras lacerato; foliis lineari-lanceolatis 
2.5-3.5 cm. longis 2—3 mm. latis integerrimis undique bene striatulo- 
venosis subnigrescentibus apice basique peracutis; spicis 2-9 cm. 
longis, internodiis rhachidum 3-10 mm. longis, ocreis 2-3-fioris; 
laminis bractearum parvis lanceolatis 2-3 mm. longis a floribus 
superatis; pedicellis nutantibus filiformibus apice articulatis; flor- 
ibus turbinato-campanulatis; calycis segmentis 5 elliptico-oblongis 
glabris 2 mm. longis pallidis epunctatis; staminibus 6; lilamentis 
glabris ; styli ramis 3 ; ovario triquetro ; fructu ignoto. — Texas : 
Drummond , no. 254 of his second expedition (type in hb. Gr.); also 
Drummond, no. 266 of his first Texan expedition (hb. Gr.); and on 
sterile prairies, granitic soil, near Llano, October, 1847, Lindheimer , 
no. 57 (hb. Gr.). 
Of P. camporum and P. striatulum I have seen no specimens 
from north of Texas. The numerous plants of Kansas, Missouri, 
Nebraska, and Dakota, which various authors have from time to 
time referred to P. camporum, have so far as I have been able to 
examine them proved to be P. avicidare, L., P. ramosissimum , 
Michx., or P. proliftcum, Robinson. These species are not difficult 
to distinguish, although from habital similarity they have been much 
confused. In P. camporum the flowers are borne on much longer 
pedicels than in P. aviculare or its variety littorale ; the flowers are 
much larger than in P . prolificum ; and the segments of the calyx, 
which are 5 in number, are far more petaloid and less strongly keeled 
than the outer calyx-lobes of the habitually 6-cleft calyx in P. ramo - 
sissimum. 
P. (§ Avicularia) leptocarpum, spec. nov. Glaberrimum 3 
dm. altum profuse ramosuin; radice lignescenti, caulibus numerosis 
teretibus delapsu foliorum nudis, ramulis 3-4-angulatis, ocreis 3 mm. 
longis basi ferrugineis, limbo profunde in fibras sordidas lacerato ; 
foliis inferioribus ignotis, superioribus lanceolato-linearibus 7 mm. 
longis 1-1.5 mm. latis crassiusculis pallide viridibus vel etiam griseis 
apice basique acutis uninerviis; floribus axillaribus minimis incon- 
spicuis sessilibus; calyce 2 mm. longis epunctato ad mediam vel 
