2812 



PROTEA 



PROTOPLASM 



densely bearded. About 100 species, mainly from S. 

 Afr. but extending into Trop. Afr. Their fl.-heads are 

 said to look like a "glorified artichoke." Indeed P. 

 cynaroides (Fig. 3195) is named from this very resem- 

 blance. (Cynaroides means cynara-like; and Cynara is 

 the artichoke.) It has bright pink fl.-heads which last 

 several months. The structure of the fl.-heads is the 

 distinctive feature of the whole family of the Proteacea?. 

 The showy parts of the fl.-head are the bracts, which 

 are often rigid, colored, and overlap one another 

 like the scales of a hard cone or an artichoke. "When 

 the heads of P. cynaroides first open," says Watson, 

 "they are full of honey and are known to the Boers as 

 honey-pots." This honey is collected and made into a 

 kind of sugar. The blooming of the "honey-pots" is a 

 great occasion, for picnics. Watson saw large bushes of 

 P. speciosa at the Cape, which he declared were quite 

 as effective as big specimen rhododendrons. "Fifty 

 years ago," writes Watson, in 1891, "there were about 30 

 species of Protea included among popular greenhouse 

 plants in England; now one may safely say there is not 

 one, the few really under cultivation being only in 

 botanical collections." In 1881, Hooker wrote: "That 

 these and many other plants requiring like treatment 

 will be reintroduced, and will be the wonders of the 

 shows for many successive seasons, is as certain as that 

 they were once the glories of the old flue-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 to 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," says 

 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 growing 

 inside a larger one, filling up the space between with silver 

 sand. The latter is always kept moist." It is suggested 

 by one grower that it is possibly not excessive watering 

 that injures them, but insufficient drainage. Many of 

 the species need staking, as the shoots are quick to 

 break off at the base if unsupported. Proteas ripen 

 seeds freely, and seeds can be easily procured from the 

 Cape. 



cynaroides, Linn. Fig. 3195. Bush, up to 6 ft. high or 

 sometimes acaulescent: Ivs. petioled, varying from 

 subrotundate and obtuse to elliptic and acute: head 

 sessile; outer involucral bracts ovate to ovate-lanceo- 

 late, inner lanceolate, oblong, acuminate, tomentose, 

 exceeding the fls.; ovary oblong, covered with long 

 whitish hairs. S. Afr. G.F. 8:35. G.C. III. 17:773. 

 G.M. 38:407. 



mellifera, Thunb. A large bush, 6-8 ft. high: Ivs. 

 hnear-oblanceolate : involucral bracts very viscid, those 

 of the stipes silky pubescent, the others glabrous, dark 

 red to whitish green with pinkish tips and margins but 

 usually rosy pink: fls. whitish, exceeded by the involu- 

 cre/ ovary covered with long golden hairs. S. Afr. B.M. 

 346. R.H. 1903:308. The oldest specific name for 

 this plant is P. repens, Linn. Mant., not Thunb., but 

 following Phillips & Stapf in Fl. Cap. 5 sect. 1:577, 

 the name mellifera is maintained. They state that "The 

 specific name repens is so inapplicable to this plant, 

 while Thunberg's name is so suitable and has been in 

 such general use that we have retained it." Var. rilbra, 

 Hort., is a form of P. mellifera which has been offered 

 in the trade abroad. 



nana, Thunb. (P. rosacea, Linn.). Smooth shrub, 2 

 ft. high, branched: Ivs. acicular, erect-spreading, acute 



or acuminate: involucral scales oblong, obtuse, the outer 

 greenish, the inner scarlet, exceeding the yellowish fls. 

 S. Afr. B.M. 7095. G.F. 4:413. G.M. 35:268, 269. 

 Good horticultural accounts of proteas are those of 

 Wm. Watson in G.F. 8:34 and 4:412, which have been 

 liberally quoted above. WILHELM MILLER. 



F. TRACY HuBBARD.f 



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 winter-protection, which 

 again covers two very distinct ideas, freezing injury 

 and mere mechanical injury. Most Cape bulbs, for 

 example, are ruined if they are frozen; tulips are not. 

 Yet Cape bulbs may sometimes be wintered outdoors 

 if they are protected by a covering 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 alter- 

 nate 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 summer and from sun- 

 scald, which are not the important considerations with 

 eastern fruit-growers. See Winter Protection. Allied 

 topics are discussed under Greenhouse, Coldframes, and 

 Hotbeds; Diseases and Insects; Weeds; Transplanting. 



PROTIUM (probably the Javan name). Bursera- 

 cese. Trees, with balsam sap: Ivs. toward the ends of 

 the branches, alternate, 3-foliate or uneven pinnate; 

 Ifts. few-paired, rather large, petiolulate, entire or 

 dentate: panicles long-peduncled, fasciculate, branched: 

 fls. small, slender-pedicelled; calyx small, cup-shaped, 

 4-6-cleft or -dentate; petals 4-6, linear-oblong; disk 

 urn-shaped; stamens 8-12; ovary sessile, 2-4-celled: 

 drupe fleshy, globose. About 50 species, mostly natives 

 of Trop. S. Amer., some species also in India, Malaya, 

 Mauritius, Madagascar, W. Indies, and Mex. P. ser- 

 ratum, Engl. (Bursera serrdta, Wall.). Sometimes 

 planted in tropics and subtropics for ornament, and 

 wood said to be used for furniture: evergreen: Ifts. 

 about 7 or more, opposite, narrow-ovate, base acumi- 

 nate, pubescent or nearly glabrous, serrulate or entire: 

 panicles axillary, lax, much branched, shorter than the 

 Ivs.: fls. very small, hermaphrodite, pubescent exter- 

 nally; calyx 5-toothed; petals 5; stamens 10: drupe 

 globose, 1-3-celled. India. 



PROTOPLASM. The living or organized cell-con- 

 tent . The difference between living and non-living things, 

 so far as it has been possible to study it, consists in the 

 fact that the former are characterized by the posses- 

 sion of protoplasm, "the physical basis of life." This 

 protoplasm is a most complex material, the seat of 

 diverse chemical reactions and physical changes, and 

 at the same time a material having a wonderful capacity 

 for correlation and growth. When the cell or living 

 organism is killed, there is no loss of substance, and 

 the material originally constituting this protoplasm 

 remains, but there is "left relatively little to suggest 

 living protoplasm. So far as is known, this non-living 

 residue can never be reendowed or activated with 

 those characteristic properties of correlation and 

 growth, and many other properties less complex, which 

 are the potential or kinetic possessions of the living. 

 It is in some ways unfortunate to call the dead material 

 by the same name as the living. 



In the living plant or animal, the protoplasmic unit 

 is the cell, usually microscopic in size, and an associa- 

 tion of cells of the same form, or with similar functions, 

 constitutes a tissue. The spores of many fungi and of 

 mosses and ferns are single cells. In plants the proto- 

 plasmic unit is usually surrounded by a resistant mem- 



