332 



HENDERSON'S HANDBOOK OF PLANTS 



PLA 



be well and carefully drained ; cleanliness 

 amongst plants and also pots is most import- 

 ant, as a high temperature favors the multi- 

 plication of insect pests. 



Plants, Unhealthy. The Eemedy. Whenever 

 plants begin to drop their leaves, it is certain 

 that tlieir health has been injured. This may 

 be due to over-potting, over-watering, over- 

 heating, too much cold, or the application of 

 such stimulants as guano, or to some other 

 cause which has destroyed the fine root- 

 lets by which the plant feeds, and induced 

 disease that may lead to death. The case is 

 not usually important enough to call in a 

 "plant doctor," so the amateur begins to 

 treat the patient, and the practic<» is, in all 

 probability, not unlilve that of some of our 

 household physicians who apply a remedy 

 that increases the disease. Having already 

 destroyed the, so to speak, nutritive organs 

 of the plant, the "stomach" is gorged witli 

 food by applying water, or with medicine by 

 applying guano or some patent " plant food." 

 Now the remedy is nearly akin to what is a 

 good one when the animal digestion is de- 

 ranged — give it no more food until it re-acts. 

 We must then, if the roots of the plant have 

 been injured from any of the above-named 

 causes, let the soil in which it is potted 

 become nearly dry; then remove the plant 

 from the pot, take the ball of soil in which 

 the roots have been enveloped, and crush it 

 between the hands just enough to allow all 

 the hard outer crust of the ball of earth to be 

 shaken off; and then re-i)ot in rather dry soil, 

 using a new flower-pot, or the old one, thor- 

 oughly washing it, so that the moisture can 

 freely evaporate thi-oughthepon^s. Be careful 

 not to over-feed the sick plant. Let the pot be 

 only lai-ge enough to admit of not more than an 

 inch of soil between the pot and the ball of 

 roots. After re-potting, give it water enough 

 to settle the soil, and do not apply any more 

 until the plant has begun to grow, unless, in- 

 deed, the atmosphere is so dry tiiat the mois- 

 ture hag entirely evaporated from the soil, 

 and then, of course, water must be given, or 

 the patient may die from the opposite cause — 

 starvation. The danger to be avoided is, in 

 all probability, that which brought on the 

 sickness, namely, saturation of the soil by too 

 much water. Other causes may induce sick- 

 ness in plants, such as an escape of gas in th(* 

 apartment, or smoke from a flue in the green- 

 - house; but in all cases, when tlio leaves fall 

 from a plant, withhold water, and if there is 

 reason to believe that the soil has been 

 poisoned by gas, or soddened with moisture, 

 shake it fn>m the roots as before advised, and 

 re-pot in a fresh flower-pot. 



Platana'ceae. A small natural order of usually 

 tall treeo, of which two are natives of eastern 

 Europe, and Asia, and the rest of North 

 America. Platanus, the only genus of the 

 order, comprises five or six species, valuable 

 for their timber as well as for their ornamental 

 appearance. 



Platanthe'ra. Native Orchids, now included in 

 the genus Habenaria, which see. 



Pla'tanus. Plane Tree, Button-wood, or Syca- 

 more. From platyti, broad or ample ; in allu- 

 sion to the spreading branches and shady 

 foliage. Nat. Ord. Platanacece. 



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P. occidentalis is the well-known Button- 

 wood tree, and is common throughout the 

 United States east of the Rocky Mountains. 

 P. orientalis, the Oriental or Common Plane, 

 is a beautiful, lai'ge, spreading tree presenting 

 a great variety of handsome forms, which 

 differ chiefly in the shape and lobing of the 

 leaves. The variety P. O. Acerifolia (maple- 

 leaved) is the commonest in cultivation, fre- 

 quently bearing the name of P. occidentalis 

 from which it may readily be distinguished 

 when in fruit, by the peduncles bearing more 

 than one ball, and frequently many. P. racem- 

 osa, a California species, is remarkable for 

 its deeply live-lobed leaves, the under surface 

 of which, even when they become old, is 

 copiously clad with woolly hairs. This spe- 

 cies furnishes a hard and durable timber, and 

 is much less liable to warp than that of P. 

 occidentalis. P. Wrightii, found on the banks 

 of rivers in the valleys of New Mexico, Arizona, 

 and northern Mexico, forms a beautiful tree 

 forty to sixty feet in height. The wood is 

 light, soft, very close-grained and compact. 

 Some fine specimens of this genus are to be 

 seen as street trees in Washington, D. C. 



Platyca'rpum. From platys, broad, and Karpos, 

 a fruit; alluding to the shape of the capsule. 

 Nat. Ord. Rubiacem. 



P. Orinocense, the only described species, 

 introduced from Orinoco in 1813, is a tall 

 tree with robust, opposite, terete branches. 

 If the plants are kept rather dry in winter, it 

 will tend to throw them into flower. 



Platyce'rium. Stag's Horn Fern. YTom platys, 

 broad, and keras, a horn ; referring to the form 

 of the fronds. Nat. Ord. PolypodiacecB. 



A very distinct and remarkable genus of 

 Ferns, formerly grouped with Acrostichum, 

 but now placed by themselves in a separate 

 genus under the name of Platycerium, because 

 they produce their sori in large amorphous 

 patches, and not, as in the true AcrostichecR, 

 over the whole fertile portions. The species 

 are few in number, chiefly Eastern or Austra- 

 lian and for the most part tropical. "They 

 have hetermorphous, coriaceous, laciniate, or 

 lobate fronds, clothed Avith stellate hairs, and 

 the fertile fronds are articulate. The broad 

 fronds are traversed by several furcate ribs, 

 between which there is a close network of finer 

 buried veins. The large, shapeless masses 

 of spore cases are attached to the plexus of 

 crowded veins, and are quite naked. In P. 

 biforme they occupy a separate scutiform lobe, 

 but in the other species they are variously 

 situated near the maigin." — Dr. Moore in Bot. 

 Treas. P. alcicorne is the type of the genus, 

 and was introduced in 1808. It is best known 

 under its common name of Stag's Horn Fern, 

 so called because of the striking resemblance 

 of the fronds to the horns of a stag. This is 

 the species commonly seen in our green- 

 houses. It is a native of New South Wales, 

 and was introduced in 1808. P. grande, a 

 native of Moreton Bay, was introduced into 

 Europe in 1828, but is still quite rare in the 

 United States. It has broader and larger 

 fronds than P. alcicorne, is a plant of altogether 

 grander proportions. To this species has 

 been given the name of Elk's Horn Fern. Mr. 

 F. W Burbidge, a well-known botanist and 

 collector, in his recent book of travels in 

 Borneo, etc. (" The Garden of the Sun ") thus 



