28 BOTANICAL GAZETTE [yuLy 
C. acaulis occurring on the slopes and crests, usually in the gravelly 
loam, while P. montanus is limited to the clay of the lowland. 
The flowers of these species are produced early and are short- 
_lived, most of the foliage being produced after the flowers and con- 
tinuing during the rainy vernal period, after which the surface parts 
disappear and the living parts lie buried until the following spring. — 
VERNAL ASPECT. | 
Habitat—Physical water: in clay 1 3-17 per cent.; in gravelly” 
loam 4.5-9 per cent. Non-available water: in clay 8.5-10 per 
cent.; in gravel 1.5-2.5 per cent. Available water: in clay 5.0-_ 
9-3 to roo of dry soil; in gravel 3.2-7.28, Rainfall 12.7- 
27-9°"; ay. daily o.3°™. Relative humidity: mean 54 per cent.; 
Tange II-too per cent. Wind 5.33'™ per hour. Temperature: 
mean 14:4 (C.; mean max. 20-5 C.; mean min. 6°4 C.; range —2.2 : 
—34°4C.; soil 12—25°C.; soil surface to 49°C. Light duration — 
67 per cent. Exposure varied, cover open, soil clay to gravel. Dura- 
tion May 1 to July rs. : | 
PRINCIPAL SPECIES: Senecio oblanceolatus Rydb.,- (Thelesperma _ inter- 
medium Rydb.), Yucca glauca Nutt., Kellermannia yuccogena Ell. & Ev., | 
Pleospora phragmospora Dur. & Mont., Astragalus Drummondii Doug]., Pent- 
stemon angustifolius Pursh, P. secundiflorus Benth., (Opuntia polyacantha Haw.), : 
(Carex stenophylla Wahl.), (Puccinia caracena DC.), Astragalus bisulcatus — 
(Hook.) Gray, Euphorbia robusta (Engelm.) Small, Uromyces scutellatus 
(Schrank) Léy., Echinocereus viridiflorus Engelm., Arenaria Fendleri Gray, 
Sophora sericea Nutt., Uromyces hyalinus Pk., (Oreocarya suffruticosa [Torr] 
Greene), (Ipomoea leptophylla Torr.). F 
SECONDARY SPECIES: Lesquerella montana (Gray) Wats., Tetraneuris : 
glabriuscula Rydb., Aragallus Lambertii (Pursh) Greene, (Astragalus mol- 
lissimus Torr.), Astragalus crassicarpus Nutt., Lappula occidentalis (Wats-) 
Greene, Allium reticulatum Don, Oreocarya thyrsiflora Greene, Euphorbia 
glyptosperma Engelm., Hymenopappus cinereus Rydb., Thalesia fasciculata 
(Nutt.) Britton, Mertensia linearis Greene, Pentstemon Jamesii Benth., Erio- ; 
gonum alatum Torr., Cactus viviparus Nutt., Malvastrum coccineum ( “ ) ; 
Gray, Cheiranthus arkansanus (Nutt.) Greene, Anogra coronopifolia (T. & G-)_ 
Britton, Gaura coccinea Pursh, Euphorbia serpyllifolia Pers., Tradescantia 
scopulorum Rose, Thelesperma gracile (Torr.) Gray, Astragalus Shortianus 
Nutt., Nothocalais cuspidata (Pursh) Greene, Erigeron pumilus Nutt., E. flagel- 
laris Gray, E. glandulosus Porter, E. canus Gray, Carex filifolia Nutt., C. pent 
sylvanica Lam., Vicia americana Muhl., Aecidium porosum Pk., Quincula 
