PHELLODENDRON 



PHILADELPHIA 



1297 



hardy as far north as Mass., but P.Japoniciim is some- 

 what tender; the first has been recommended as a street 

 tree for western cities, as it resists drought and heat in 

 summer and seems to be not attacked by insects. It is 

 of rapid growth when young and forms a rather low, 

 round head. It seems to grow in almost any kind of 

 soil except in a very moist one. Prop, by seeds, which 

 are produced freely when both sexes are planted and by 

 root cuttings, dug up in fall and stored during the 

 winter in moist sand or sphagnum. Two closely related 

 species in E. Asia and Japan. Fls. dioecious, in terminal 

 short panicles; sepals and petals 5-8, ovate-lanceolate; 

 stamens 5-6, longer than petals: ovary 5-celled, with a 

 short, thick style: fr. a black drupe with 5 small one- 

 sgiMled stones. 



Amur6nse, Rupr. CHINESE CORK TREE. Tree, to 50 ft., 

 with spreading branches forming a broad, round head; 

 bark of the trunk light gray, corky; almost glabrous: 

 h'ts. 7-17, ovate to ovate -lanceolate, narrowed or 

 rounded at the base, long-acuminate, minutely crenu- 

 late, dark green and somewhat shining abo've,glaucescent 

 and glabrous beneath or pubescent only on the midrib: 

 fr. globose, black, about % in. across, with a strong 

 turpentine-like odor when bruised. June. N. China, 

 Amurland, Japan. 



Jap6nicum, Maxim. Closely allied to the preceding. 

 Lfts. ovate, rounded or truncate at base, acuminate dull 

 green above, pubescent beneath, with rather prominent 

 veins; leaf-stalk and inflorescence pubescent. June. 

 Japan. Less hardy than the preceding and probably 

 only a variety of it; but sometimes thrives in New 

 England. ALFRED REHDER. 



PHENOLOGY (contraction of phenomenology; that 

 is, the science of phenomena) : the study of the rela- 

 tionships between the climate of any place and the 

 annual periods of plants and animals. Plants vege- 

 tate, bloom, and ripen fruit at more or less definite 

 seasons, each after its kind; animals mate, bear young, 

 migrate and hibernate each also after its kind; but 

 these recurring events are related to the climate in 

 which these things live: with these inter-relationships 

 Phenology 'has to do. The most complete means of 

 comparing the climate of one year with that of another 

 are the life-events of the animals and plants of the 

 years. Thermometrical readings are the customary 

 measures, but the thermometers record only tempera- 

 ture, whereas local climate is modified by conditions 

 of humidity, cloudiness, the sequence of atmospheric 

 changes, and many subtle agencies which cannot be 

 measured by means of instruments. Living things are 

 the agents that really measure climate. A record of 

 the life-events of living things, therefore, even though 

 imperfect, should contribute to the science of clima- 

 tology; and incidentally it should contribute much to 

 the science of biology. Records of plant-events are 

 more comparable than those of animal-events, because 

 plants are stationary and have no volition to adapt 

 themselves to inclemencies by means of change of po- 

 sition, diet, or otherwise; therefore, plants emphati- 

 cally express climatal influence. A record of the first 

 blooming of a given apple tree, for example, during a 

 ^i-rics of years woiild give comparable measures of the 

 lateness or earliness of the different seasons. Most 

 so-called phenological observations in this country have 

 hem mere records of dates of blooming, leafing, migra- 

 tion of birds, peeping of frogs, and the like, without 

 correlative data respecting the local climate. They are 

 therefore of relatively little consequence to science. In 

 this country the literature of Phenology is very meager. 

 See Bailey, Essay 17, "Survival of the Unlike," and 

 "Instructions for taking Phenological Observation," 

 "W.uther Review," Sept., 1896, U. S. Weather Bureau. 



L, H. B. 



PHILADlSLPHUS (name of an ancient Egyptian 

 kiny:: applied to this genus with no obvious reason). 

 Saxifragacece. MOCK ORANGE. SYRINGA. Ornamental 

 deciduous or rarely half -evergreen shrubs with opposite 

 entire or serrate Ivs. and white showy fls. in terminal ra- 

 ('mes or solitary on short branchlets, appearing mostly 

 in June and often very fragrant. Most of them are 

 hardy North except P. Coulteri, Mexicanus and the 



other Mexican species; P. tomentosus and Billardi are 

 only half-hardy. They are well adapted to shrubberies 

 and are mostly of medium height, the tallest being P. 

 pubescens, which grows to about 20 ft.; P. Gordoni- 

 anus and P. inodorus grow nearly as high, while 

 P. microphyllus hardly exceeds 3 ft. They thrive well 

 in almost any well-drained soil and even under trees. 

 If pruning is needed it should be done after flowering, 

 since the fls. appear on the wood formed the previous 

 year. Prop, usually by hardwood cuttings, or by 

 suckers and greenwood cuttings under glass; also by 

 layers and by seeds, but they are very apt to hybridize 

 when several species are growing together. 



About 30 species have been described. They are dis- 

 tributed through the northern hemisphere ; in N. Amer. 

 south to Guatemala and from southeast Europe to 

 Himalayas and Japan. All are shrubs with exstipulate, 

 petioled more or less distinctly 3-nerved Ivs. : fls. solitary 

 or racemose; calyx-lobes, petals and styles usually 4; 

 stamens 20-40: fr. a dehiscent, 4-valved, many-seeded 

 capsule. Owing to the absence of well-marked charac- 

 ters the species are often rather difficult to distinguish, 

 and this difficulty is much increased by the numerous 

 hybrids which have originated in cultivation. The 

 latest account of this genus is a short monograph by 

 E. Koehne in Gartenflora, Vol. 45 (1896), p. 450, etc., 

 where 33 species are distinguished, of which 20 are 

 American. 



It seems strange that Philadelphus is popularly 

 known under the name of Syringa, a very different 

 genus of no botanical affinity and little resemblance; 

 but this is only continuing the usage of the old 

 herbalists who used to unite under Syringa species of 

 Philadelphus, Syringa and Jasmine. Thus we find in 

 Gerarde's "Herball," first published in 1597, descrip- 

 tions and figures of Syringa alba, White Pipe, S. 

 ccerulea, Blue Pipe, and S. Arabica, Arabian Pipe, the 



1748. Philadelphus coronarius Mock Orange (X 



first being Philadelphus coronarius, the second Syringa 

 vulgaris and the third Jasminum Sambac. This 

 accounts also for the German popular name Jasmine 

 for Philadelphus. In French Syringa has been changed 

 to Seringa, and is used in this form as the popular 

 name for Philadelphus. Linnaeus decided to take up 

 the name Syringa for the S. ccerulea of the older 

 botanists and Syringa alba he called Philadelphus, a 

 name previously used for the same plant by some of the 

 old herbalists. 



