1918.] HORTICULTURE. 749 



which have been grown in Porto Rico over a long period of years. A compara- 

 tive test of a new stock of these varieties is to be made. Among the native 

 sweet potatoes one with superior qualities, known locally as mamey, is being 

 propagated for distribution. 



Two types of the leguminous plant Phaseolus mungo received from the 

 Philippine Islands have proved very thrifty and prolific at the station when 

 planted during the spring, although poor crops have resulted from summer, 

 fall, and winter plantings. The cooked seed of this plant is palatable as food 

 and its heavy foliage makes it valuable as a soil improver or cover crop. 



A variety of banana known as Hua Moa received by the station from Hawaii 

 several yeai-s ago is giving some promise as a cooking banana, although it does 

 not appear to thrive well except when given good applications of stable manure. 



Report of tlie assistant horticulturist, T. B. McClelland {Porto Rico Sta. 

 Rpt. 1916, pp. 21-24). — The testing of coffee varieties new to Porto Rico was 

 continued and promising varieties are being distributed widely. Observations 

 on an extensive planting of Robusta coffee indicate that it is inferior in quality 

 to that of the Arabian type grown in Porto Rico, but its heavier yield makes 

 it a promising crop for supplying a low-priced market. This coffee matures 

 later than the native coffee, the main crop ripening in late winter and early 

 spring rather than in autumn. This is suggested as being an advantage as it 

 furnishes employment to pickers in a dull season. The rank growth of the 

 trees necessitates topping to 7 or 8 ft. to facilitate picking. The coffee locally 

 Icnown as " Murta " has proved to be a mongi-el and inheritance ©f different 

 forms is being studied. The experimental transplanting of coffee trees con- 

 tinues to show wide differences both in growth and yield as the result of the 

 method followed. This work is discussed in detail in a separate report (E. S. 

 R., 37, p. 649). Fertilizer experiments with coffee contimae to show beneficial 

 effects, both on growth and crop, from the application of nitrogen. A native 

 tree of dwarf growth (Erythrina corallod-endron) , not hitherto used locally as 

 coffee shade, is being tested for this purpose. Plantings without shade of differ- 

 ent coffee varieties are also being made to compare their relative vigor in 

 the open. 



Records have been kept of the number of pods produced on individual cacao 

 trees for several years. Of plantings made in the spring of 1909 a little more 

 than one-fourth of the trees produced no crop in the calendar year 1915. The 

 others averaged nearly 10 pods per tree. In plantings made in 1903 about the 

 same proportion of trees failed to produce but the average yield from the fruit- 

 ing trees was 6.5 pods per tree. Attempts to propagate cacao from cuttings 

 have been unsuccessful. 



The experiments thus far conducted witii vanilla show this to be a promising 

 crop for Porto Rico. It requires careful attention and a great deal of labor, 

 but with proper conditions large returns may be secured from a small acreage. 

 In crossing vanilla species some very marked modifications, here noted, in the 

 shape of the resulting pod have followed the application of foreign pollen. A 

 new planting of vanilla has been made for further tests of the effects of light 

 and dense shading, different pruning systems, the removal of superfluous blos- 

 soms, and the pollination of few to many blossoms per cluster. 



Trees of mahogany {Sioietenia iiuici'ophylla) continue to show adaptability 

 to local conditions. In a planting made at the station the average height at 

 3 years from seeding was 16 ft, the maximum height 30 ft 



Bush beans in the greenhouse, S. N. Gbeen {Mo. Bid. Ohio Sta., 3 {1918), 

 No. 1, pp. 16-20, figs. 2). — Experiments on the greenhouse culture of bush beans 

 conducted during the three seasons 1915-1917 are reported. 



