(1) Definitions(2) The physical process of transpiration: (a) Water‐absorption by roots; (b) transmission to membranes from which evaporation occurs; (c) cuticular transpiration; and (d) stomatal transpiration.(3) Factors controlling the rate of plant‐discharge by transpirations (a) Physiological; (b) environmental including (l) above soil (or water) surface and (2) below soil (or water) surface; and (c) relative importance of various factors.(4) Methods of measuring plant‐discharge by transpiration! (a) Potometer (end of severed plant or branch in sealed vessel of water); (b) phytometer (growing plant in sealed pot or tank); (c) cobalt chloride; (d) Freeiian method; and (e) rate of moisture‐loss from freshly cut plants determined by weighing.(5) Methods of measuring consumptive‐use: (a) Single plant or type of vegetation including (l) tank or pot (unsealed) and (2) experimental field‐plot; (b) agricultural crops in Irrigation‐projects or valleys including (1) measuring percolation‐ loss from irrigated land by determining annual increase in spring or seepage flow below tract, (2) net depletion of river‐water by irrigated lands drained either naturally or artificially, (3) relation of aggregate irrigation‐diversion to change in level of ground‐water, (4) soil‐moisture determinations before and after irrigation, (5) application of re suits of tank or field‐plot experiments to classified acreage with similar climatic and soil‐conditions, and (6) relation of available heat to consumptive use; (c) agricultural or mixed vegetation in valleys including (1) adaptation of methods developed in ground‐water hydrology for quantitative estimating of ground‐water supplies; (d) mixed vegetation in stream drainage‐areas including (1) graphical method baaed on rainfallrunoff relation (Grunsky, Rafter, Lee, etc.) , (2) rational method using formula (Russell, Vermuele, Justin, etc.), and (3) rational method by computation from rainfall and other physical data (Meyer); (e) vegetation with roots in capillaryfringe including (1) method by interpretation of continuous records of fluctuation of water‐table.(6) Quantitative experimental work—(A) Relation of water‐loss by cuticalar and stomatal transpiration to total plant‐disoharge(B) Total plant‐discharge by transpiration.List under vegetational type and describe under following sub‐headings all published or current work, principally by botanists and foresters Main headings (vegetational type)(1) Natural vegetation including (a) Western (semi‐arid climate) for (l) forest under coniferous and woodland (on stream‐borders, bottomlands, and slopes); (2) shrub under chaparral, sagebrush, creosote (mixed desert shrubs), and greasewood and alkali‐resistant shrubs; (3) grassland (grass‐like plants and herbs) under bunch grass, short grass, semi‐desert grassland (southwest), mountain meadows, swamp and marsh vegetation (rush, sedge., reed, etc.), foothill annuals (Pacific Coast), and alkali‐resistant grass (salt grass, etc.); and (b) Eastern (humid climate) for (l) forest under coniferous and hardwood or broad leaf; (2) grassland for prairie, swamp and marsh (rush, sedge, reed, etc.), and grass in timber (understory of grasses and herbs). (2) Cultivated vegetation including (a) orchard trees (citrus, deciduous, etc); (b) vines (grapes, climbing berries, etc. ); (c) annual fieldcrops (corn, potatoes, etc.); (d) perennial field crops (alfalfa, etc.); (e) garden‐truck; and (f) weeds.Sub‐headings (description) (1) Water‐supply including (a) precipitation for (1) winter maximum ‐ summer minimum, (2) winter minimum ‐ summer maximum, and (3) two maxima, winter and summer; (b) shallow water‐table; (c) flowing stream; (d) swamp or marsh; (a) surface‐irrigation; and (f) salt marsh, desert playa, etc. (2) Location. (3) Inclusive dates of observation. (4) Period of observation for (a) hour, (b) day, (c) week, (d) month, and (e) year. (5) Method of observation including (a) equipment and (b) application of water. (6) Authority. (7) Published reference.(C) Consumptive use (plant‐discharge by transpiration plus evaporation from surrounding soil).