AND GENERAL HORTICULTURE. 



315 



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base of the lip. They should be grown in 

 well-drained pots of light, rich, fibrous loam, 

 with a liberal mixture of fine sand and broken 

 charcoal. They succeed well in an ordinary 

 green-house, but are impatient-of much water, 

 particularly when at rest. They flower during 

 the summer months, and remain in bloom 

 several weeks. It is propagated by division, 

 and was introduced in 1826. 



Peristro'phe. From peristrophe, turning round, 

 in reference to the corolla, which is twisted 

 so as to be upside down. Nat. Ord. Acan- 

 thacecB. 



A small genus of green-house herbaceous 

 plants, natives of India, with small purple 

 flowers produced in winter, and continuing in 

 full beauty for several weeks. P. angustifolia 

 variegata, an ornamental plant, with foliage 

 variegated with j'ellowish-white and green ; it 

 is a very useful plant in window gardening or 

 rustic woi'k, and is propagated readily by cut- 

 tings. 



Peri'toma. From peritome, a cutting round 

 about ; referring to the base of the calyx. Nat. 

 Ord. CapparidacecE. 



A small genus of hardy annual herbs now 

 included by Bentham and Hooker under 

 Cleome. P. aurea is the only species of inter- 

 est. 



Periwinkle. See Vinca. 



Perne'ttya. Named after Don Pernetty, author 

 of "A Voyage to the Falkland Islands." Nat. 

 Ord. EricacecB. 



A genus of half-hardy evergreen, white 

 flowering shrubs, natives of Mexico and Peru. 

 They are not sufficiently hardy to endure our 

 winter without protection, and have no merits 

 that entitle them to a place in the green-house. 



Perono'spora. A genus of minute Fungi, all 

 growing in, or upon living plants. The species 

 that has done most harm and is most to be 

 dreaded is the Potato disease Fungus, P. infes- 

 tcCns, known also as Phytophthora infestans. 

 There are many other species that attack 

 various vegetables such as Parsley, Carrots, 

 Turnips, Cabbages, Peas, Spinach, etc., and 

 are frequently most injurious to these plants. 

 As it is now well understood that these Fungi 

 live inside the host-plants, and that it is 

 impossible to destroy the parasite without 

 destroying the plant, all efforts should be 

 directed against the spread of the disease, 

 since a cure of the diseased plant is practi- 

 cally hopeless. All diseased plants are liable 

 to communicate the disease to healthy plants 

 and should, if possible, be burned, that being 

 the only certain means of preventing the 

 spread of the disease. 



Perse'a. Alligator or Avocado Pear. A name 

 applied by Theophrastus to an Egyptian tree. 

 Nat. Ord. LauracecB. 



The Alligator Pear, a native of the West 

 Indies, grows upon a tree about the size of 

 the Apple-tree. The tree has oblong, veiny 

 leaves, and yellowish-green flowers. The fruit, 

 which is the size of a large Pear, is considered 

 by the natives one of the most delicious in the 

 world, though strangers do not at first relish 

 it. It contains a lai-ge quantity of firm pulp, 

 possessing a buttery or marrow-like taste, 

 and is therefore frequently called Vegetable 

 Marrow or Midshipman's Butter. It is usually 

 eaten with spice, lime-juice, or pepper and 



PET 



salt. The trees cannot be induced to grow 

 excepting in tropical or sub-tropical countries. 



Persian Po-wder. A valuable insecticide manu- 

 factured from the flowers of Pyrethruvi roaeum 

 and other species. 



Pe'rsica. The Peach. So named from Persia, 

 its supposed native country. Nat. Ord. 

 RosacecB. 



A small genus now included by Bentham 

 and Hooker under Prunus. P. vulgaris and 

 its variety P. V. Imvis are well known and 

 much esteemed fruits; forcultui-e and descrip- 

 tion of which, see Peach and Nectarine. 



Persica'ria. A common name for Polygonum 

 Persicaria. 



Persimmon. See Diospyros Virginiana. 



Persimmon. Japanese. See Diospyros Kaki. 



Persistent. Remaining beyond the period 

 when such parts commonly fall, as the leaves 

 of evergreens, and the calyx, etc., of such 

 flowers as remain during the growth of the 

 fruit. 



Personate. Masked ; a bilabiate corolla, with a 

 projection or jjalate in the throat, as of the 

 Snapdragon. 



Perso'onia. Named after C. H. Persoon, author 

 " Synopsis Plantarum " and other botanical 

 works. An extensive genus of Proteacem, com- 

 prising some sixty species of green-house 

 ornamental shrubs found in most parts of 

 Australia. One species, P. Toro, a lofty tree, 

 is found in New Zealand. A number of 

 species are in cultivation, and are admir- 

 able for large conservatories. They are 

 propagated by cuttings of the ripened shoots. 



Pertuse. Having slits or holes. 



Peru. Balsam of. Myroxylon Peruiferum. 



Peru. Mars'el of. See Mirabilis Jalapa. 



Peruvian Bark. See Cinchona. 



Peruvian DafTodil. A common name for Hymen- 



ocallis {Isviene) Calathina. 



Pes. The Latin for the foot or stalk ; as in com- 

 pounds, Brevipes, short-stalked ; Longipes, 

 long-stalked, etc. 



Pescato'rea. A genus of Orchids now included 

 under Zygopetalum. 



Petaloste'mon. Prairie Clover. From petalon, 

 a petal, and stemon, a stamen, referring to the 

 peculiar union of these organs in this genus. 

 Nat. Ord. LeguminoscB. 



A genus of hardy or lialf-hardy perennial 

 herbs closely allied to Dalea, natives of the 

 southern United States. The flowers are rose- 

 colored, purplish violet, or white. P. candidus, 

 and P. violaceus are both good subjects for the 

 herbaceous border. 



Petaloid. Similar to a petal in color and 

 texture. 



Petals. The division of the corolla, or flower 

 when they are not united to each other by 

 their edges. 



Petasi'tes. From petasos, an umbrella ; alluding 

 to the size of the foliage. A genus of Com- 

 positcB, natives of Europe, Asia and North 

 America. Many of the species formerly 

 included under Tussilago, have now been 

 referred to this genus. They are principally 

 coarse-growing weeds though some of the 

 species being very early flowering are worth 



