PROTEA 



PROTOPLASM 



1439 



shows for many successive seasons, is as certain as that 

 they were once the glories of the old tine-heated houses 

 that our forefathers called stoves, in which orchids 

 quickly perished, and Banksias and Proteas throve 

 magnificently." Over 40 colored plates of Proteas have 

 been published, of which 23 appeared in Andrews' Bot. 

 Rep. between 1797 and 1811. 



The interest in proteaceous plants is growing in 

 southern California. Proteads have a reputation for 

 being difficult t(5 cultivate away from the Cape, but 

 Hooker's statement seems to indicate that their culture 

 is not so much difficult as special. Under glass they are 

 said to require a coolhouse which is airy and sunny. 

 "The one great danger to cultivated Proteads," 

 Watson, "is excessive watering, and to 

 guard against this it is found to be a good 

 plan, in the case of delicate species, to 

 place the pot in which the plant is grow- 

 ing inside a larger one, filling up the 

 space between with silver sand. The lat- 

 ter is always kept moist." Many of the 

 species need staking, as the shoots are 

 quick to break off at the base if unsup- 

 ported. 



The family Proteaceae contains 14 gen- 

 era, of which 10 are typical of southern 

 Africa and 4 of Australia. According to 

 Bentham and Hooker, the family is as dis- 

 tinct as possible and has never been con- 

 fused by any one with anything else. The 

 most popular member of the family for 

 greenhouse culture in America at present 

 is the Silk Oak, or Grevillea. In southern 

 California the interest in the family is now 

 centered on the Silver Tree, Leucaden- 

 dron, which is the characteristic tree about 

 Cape Town and practically the only native 

 tree of any kind growing there in quantity. Proteas 

 ripen seeds freely, and seeds can be easily procured 

 from the Cape. Of recent years the two species which 

 have attracted the most attention in the horticultural 

 world are P. cynaroides (G.F. 8:35. G.C. HI. 17:773. 

 G.M. 38:407. Century Book of Gard. 310), and P. nana 

 (B.M. 7095. G.F. 4:413. G.M. 35:268, 269). 



The Australian Proteaceae are monographed in the 

 Flora Australiensis. Good horticultural accounts are 

 those of Wm. Watson in G.F. 8:34 and 4:412, which 

 have been liberally quoted above. -yy^ ]y[_ 



PROTEADS. Same as Proteacece. 



PROTECTION, as used by the gardener, is an indefi- 

 nite term. A plant may need protection from living 

 agencies, as animals, birds, insects, or plants (includ- 

 ing fungi and weeds)— or it may need protection from 

 the weather, — heat, cold, rain, drought. Generally, 

 however, the gardener means by "protection," winter- 

 protection, which again covers two very distinct ideas. 

 Most Cape bulbs, for instance, are ruined if they are 

 frozen; tulips are not. Yet Cape bulbs can sometimes 

 be wintered outdoors if they are protected by a cover- 

 ing heavy enough to keep out frost. Strawberries, on 

 the contrary, are covered after frost with a light mulch, 

 which is designed merely to keep the plants from being 

 heaved by alternate freezing and thawing. These are 

 the main objects of winter protection in the East, at 

 least with herbs. In the prairie states the fruit trees 

 also need protection from the hot, drying winds of sum- 

 mer and from sun-scald, which are not the important 

 considerations with eastern fruit-growers. See Winter 

 Protection. Allied topics are discussed under Green- 

 house, Coldframes and JTotbeds; Insects, Insecticides, 

 Fungicides and Weeds; Transplanting. 



PROTOPLASM. A substance, sometimes called the 

 physical basis of life, apparently universally present 

 and functional in all living bodies, plants and animals 

 alike. It varies greatly in consistence, owing to the 

 proportional amount of water contained, from a semi- 

 fluid to a firm solid; and its chemical composition is 

 constantly changing by its own constructive and destruc- 

 tive activitv. The slimy substance observed when bark 



is separated from rapidly growing stems is mainly pro- 

 toplasm, and is a good illustration of its condition in 

 young tissues and of its appearance in quantity. 



As usually seen under the microscope in the cells of 

 living plants, protoplasm is a mucilaginous or plastic 

 mass, nearly transparent, colorless or gray from the 

 numerous fine embedded granules, and often exhibits 



1962. Protea cynaroides (X Vg). 



streaming or other kinds of motion. It fills very young 

 and actively forming cells completely full, like thin 

 jelly in a glass flask. But as growth continues bubbles 

 of clear water appear, which soon enlarge and then 

 coalesce, so that at length the protoplasm becomes a 

 thin lining to the cell-wall and incloses a central body 

 of water. Not unfrequently, however, several strings 

 or bands, more or less branched, of the soft substance 

 stretch through the water across the cell, and in these 

 may often be observed streams of moving granules. 

 The protoplasmic layer or lining as described remains 

 as long as the cell lives and is, in fact, the only part of 

 the cell which exhibits any of the phenomena of vitality. 

 When it disappears, as it does from the heart-wood and 

 outer bark of trees and often of other plants, the tissues 

 are lifeless, and any functions they subsequently per- 

 form are solely mechanical or physical. 



In living cells of all plants (except, perhaps, certain 

 algsB and fungi) there is a specialized and very impor- 

 tant portion of the cell-protoplasm, usually spheroidal or 

 disk-form, called the nucleus. The whole protoplasmic 

 mass is capable of absorbing nutriment and of appro- 

 priating it in its own growth, and it is all sensitive to 

 external agents or stimuli, like heat, light, mechanical 

 shock, etc. ; but the nucleus is essential to cell-multi- 

 plication and to reproduction. No new cells are ever 

 formed, unless in the plants excepted above, without 

 the active aid of these minute but peculiarly endowed 

 bodies; hence no growth, beyond the simple enlarge- 

 ment of cells previously formed, can take place with- 

 out them. Cells increase by the self-division of those 

 already existing, and in this the nuclei are the active 

 agents. Two new cells are actual, though enlarged, 

 halves of one former cell; the young cells, therefore, 

 repeat the characteristics of the old one as nearly as any 

 such transmission can take place. In sexual reproduc- 

 tion there is a definite and essential coalescence of two 

 nuclei into one, and the result springing from the latter 

 is necessarily a union of the characteristics of both 

 parents; but in other cell-formations there is no such 

 chance for departure from the preexisting type. This 

 explains why the characteristics of stock and cion do 

 not become mixed however intimate the union; the 

 tissues adhere together and nutrient fliiids pass up or 

 down, but there is no intermingling beyond this. No 

 cell becomes half-and-half of stock and cion. Each pre- 



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