34 BULLETINS OF THE BUREAU OF PLANT INDUSTRY. 



of the principal distingnishinj? characters of bluegrass seeds ; descriptions of 

 species ; Poa pratensis L., Kentucky bluegrass, June grass ; Poa conipressa L.. 

 Canada bluegrass, flat-stemmed l)luegrass ; Poa trivialis L., rough-stalked 

 meadow grass; Poa nemoralis L., wood meadow grass; Poa triflora Ehrh. 

 (P. flava L., P. serotina P^hrh.), fowl meadow grass, false red top ; Poa arach- 

 nifera Torr.. Texas bluegrass ; Poa annua L., annual meadow grass ; Poa 

 alpina L., alpine meadow grass ; Poa sudetica Haenke ; Panicularia spp. : Pani- 

 cidaria nervata (Willd.) Kuntze, nerved manna grass, sometimes called fowl 

 meadow grass; Panicidaria americana (Torr.) MacM., reed meadow grass, 

 water meadow grass, tall manna grass — Weed seeds commonly found with com- 

 mercial bluegrass seeds: Bursa bursa-pastoris (L. ) P)ritton, shepherd's-purse ; 

 Lepidium virginicnm L., peppergrass ; Cerastium vulgatum L., mouse-ear chick- 

 weed; Alsine media L.. common chic]<weed ; Alsine graminea (L.) Britton ; 

 ("arduus arvensis (L.) Robs., Canada thistle ; Taraxacum taraxacum (L.) Karst., 

 dandelion ; ^latricaria inodora L.. scentless camomile ; Hieracium sp.. hawk- 

 weed ; Anthemis cotula L., dog fennel, mayweed; Chenopodium album L.. 

 lamb's quarters, pigweed ; Plantago lanceolata L., rib-grass, buckhorn, English 

 plantain ; Rumex cripspus L., curled dock ; Rumex acetosella L., sheep's sorrel, 

 sorrel ; Veronica arvensis L., corn speedwell ; Juncus tenui.s, Willd., slender 

 rush; Juncoides campestre (L.) Kuntze, field rush; Juncoides albida DC, 

 wood rush ; Carex cephalo])hora Muhl.. oval-headed sedge — Ergot occasionally 

 fouud iu commercial bluegrass seed : Claviceps purpurea (Fr.) Till., ergot. 



* No. 85. The Principles of Mushroom Growing and Mushroom 



Spawn Making. By B. M. Diiggar, Professor of Botany 



in the University of Missouri, and Collaborator of the 



Bureau of Plant Industry. 11)05. (50 pp., 7 pis. Price, 



10 cents. 



Contents : Introduction — General considerations — ^Market conditions — Ger- 

 mination studies : Review of earlier work ; experimental work — Tissue cid- 

 tures — X\itrition : Growth 07i manure and other comjjlex media; growth on 

 chemically known media; tabulation of special results; acid and alkaline 

 media — Temperature and moisture — Preparation of the compost — Installa- 

 tion of beds — Spawning and casing the beds — Mvishroom growing : Experi- 

 ments at Columbia, Mo. ; variability in mnshrooms grown under diflferent con- 

 ditions ; the cultivation of various species of mushrooms; cooperative experi- 

 ments — Cave facilities in the United States — Open-air culture — Mushroom 

 spawn making : A "chance" method ; a "selective" method ; pure-culture pre- 

 cautions ; the tissue-culture method ; the commercial process — The vitality 

 of mushroom spawn. 



No. SO. Agriculture Without Irrigation in the Sahara Desert. By 



Thomas H. Kearney, Physiologist. 1905. 30 pp., 5 pis., 



1 fig. Price. 5 cents. 



Contents : Introduction — Population — Climate — Water supply — Soils — The 

 date gardens : Planting ; care of palms ; fighting the sand : manuring ; har- 

 vest ; yields ; varieties chiefly grown — Conclusion — Description of plates. 



No. 87. Disease Resistance of Potatoes. By L. E. Jones, Botanist of 

 the Vermont Agricultural Experiment Station and Col- 

 laborator of the Bureau of Plant Industry. 1905. 39 pp. 

 Price, 5 cents. 



Contents : Introduction — Potato culture in Europe — Observations on potato 

 diseases and disease resistance in Europe : Certain minor diseases ; internal 

 brown spot ; filosite, or growing-out ; leaf-spot ; scabbiness of tubers ; potato 

 scab; varietal resistance to scab; other scab-like diseases; potato stem dis- 

 eases; blackleg: other stem diseases ; late-blight and rot due to Phytophthora 

 infestans — Resistance as shown toward late-blight and rot: Historical state- 

 ment ; the meaning of disease resistance ; disease resistance and vegetative 



101 



