Inventory of the flora of Big Bend National Park Brewster County ...

[Records: Tornillo Flats, 28 Jun 1941, Warnock 21681 (F, NY, PH, BRIT, TEX-LL);
BBNP, Keil & McGill 7818 (OS); Smoky Creek (Sperry, 1938)]
Pectis prostrata Cav.
[Sperry, 1938]
[Brewster Co.: Oak Creek Canyon (Sperry, 1938)]
Pericome caudata Gray Tailleaf Pericome
[Sperry, 1938; Powell, 1973; Powell, 1998]
[Brewster Co.: slopes of Casa Grande (Sperry, 1938); upper Green Gulch, Chisos
Mts., Powell 1554 (SRSC) (Powell, 1973, 1998)]
Perityle aglossa Gray Rayless Perityle
[Powell, 1998]
[Brewster Co.: near Big Bend tunnel, 4 mi. W of Hot Springs and San Vivente
Canyon (Powell, 1998)]
Perityle dissecta (Torr.) Gray Slimlobe Rockdaisy
[Powell, 1998]
[Brewster Co.: Santa Elene Canyon (Powell, 1998)]
Perityle parryi Gray
[Steyermark & Moore, 1933; Sperry, 1938; Powell, 1998]
[Brewster Co.: Pulliam Canyon and Oak Creek Canyon (Sperry, 1938, #301 & 753);
Chisos Mts. and vicinity including Santa Elena Canyon (Powell, 1998); Santa Elena
Canyon, Moore & Steyermark 3466 (MO)]
Perityle rupestris (Gray) Shinners var. albiflora Powell
[Laphamia rupestris Gray]
[Sperry, 1938; Powell, 1998]
[Records: top of Casa Grande (Sperry, 1938, #742)]
Perityle vaseyi Coult. Margined Perityle
[Sperry, 1938; Powell, 1998]
[Records: hills N of Chisos Mts., Hot Springs and Fisk Canyon (Sperry, 1938);
near Hot Springs to near Costolon (Powell, 1998); Tunnel W of Rio Grande Village,
BBNP, 28 May 1982, Toolin s.n. (UTEP)]
Pinaropappus roseus Less. White Rock Lettuce
[Sperry, 1938]
[Records: Basin (Sperry, 1938)]
Pluchea sericea (Nutt.) Cav. Arroweed
[Tessaria sericea (Nutt.) Shinners]
[Sperry, 1938; Powell, 1998]
[Records: Tornillo Flats and Chisos Pens (Sperry, 1938); Chisos Mts. area,
Tornillo Creek and Chisos Pens (Powell, 1998)]
Porophyllum scoparium Gray Poreleaf
[Sperry, 1938; Johnson, 1969; Powell, 1998]
[Records: Oak Creek Canyon, Muskhog Spring, Chisos Pens and W
slope of Dead Horse Mts. (Sperry, 1938); Chisos Mts., Blue Creek, June 1931, Mueller 8240
(F, GH, MICH, MO, NY, TEX-LL, UC, US)]
Psathyrotes scaposa Gray
[Sperry, 1938; Strother & Pilz, 1975, mapped]
[Records: hills and slopes N of Hot Springs (Sperry, 1938)]
Psilostrophe gnaphalioides DC.
[Sperry, 1938; Heiser, 1944; Brown, 1977; Brown, 1978, mapped]
[Brewster Co.: Persimmon Gap area and lower Green Gulch (Sperry, 1938); 1.2 mi. N of
Persimmon Gap Ranger Station, Keil 7830 (ASU); Chisos Mts., Young (TEX-LL); Chisos
Mts., Sperry 743 (US)]
Psilostrophe tagetina (Nutt.) Greene Wooly Paperflower
[Sperry, 1938; Heiser, 1944; Brown, 1977; Brown, 1978, mapped]
[Brewster Co.: Basin, Green Gulch, Mesa de Anguila and Panther Spring (Sperry, 1938);
1.5 mi. N of Castolon, Keil 7802A and 7802 (ASU); Chisos Mts., Mueler 8231 (GH; MO; NY;
TEX-LL); Willow Creek and Green Gulch Canyons, Sperry 250 (US); lower Green Gulch,