59 



organization, and the difference be- 

 tween Exogens and Endogens is often 

 disguised or obliterated by irregu- 

 larities of- growth or by the pro- 

 duction of. large quantities of cellular 

 tissue filled with starch or other 

 substances. There is seldom, if ever, 

 any distinct pith ; the concentric circles 

 of iibro-vascular tissue in Exogens are 

 often very indistinct or have no re- 

 lation to seasons of growth, and the 

 epidermis has no stomates. Boots grow 

 in length constantly and regularly at 

 the extremities only of their fibres, in 

 proportion as they find the requisite 

 nutriment. .Their fibres proceed irregu- 

 larly from any part of their surface 

 without previous indication, and when 

 their growth has been stopped for a 

 time, either wholly by the close of the 

 season or partially by a deficiency of 

 nutriment at any particular spot, it 

 will, on 'the return of favourable cir- 

 cumstances, be resumed at the same 

 point, ff the growing extremities be un- 

 injured. If during the dead season, or 

 at any othertime,thegrowingextremity 

 is cut off, dried up, or otherwise injured, 

 or stopped by a rook or other obstacle 

 opposing its progress, lateral fibres will 

 be formed on the still living portion, 

 thus enabling the root as a whole 

 to diverge in any direction, and travel 

 far and wide when lured on by appro- 

 priate nutriment. This growth is not, 

 however, by the successive formation 

 of terminal cells attaining at once their 

 full size. The cells first formed on a 

 fibre commencing or renewing its 

 growth will often dry up and form a 

 kind of terminal cap, which is pushed 

 on as cells are formed immediately 

 under it ; and the new cells, constituting 

 a greater or lesser portion of the ends 

 of the fibres, remain some time in a 

 growing state before they have attained 

 their full size. The functions of the 

 root are — first, to fix the plant in or to 

 the soil or other substance on which it 

 grows ; second, to absorb nourishment 

 from the soil, water, or air into which 

 the fibres have penetrated (or from 

 other plants in the case of parasites), 

 and to transmit it rapidly to the stem. 

 The absorption takes i>lace through the 

 young growing extremities of the fibres, 

 and through a peculiar kind of hairs or 

 absorbing organs which are formed at 

 or near those growing extremities. The 

 transmission to the stem is through the 

 tissues of the root itself. The nutri- 

 ment absorbed consists chiefly_ of 

 carbonic acid and nitrogen, or nitro- 

 genous compounds dissolved in water. 

 Third, in some cases the roots secrete 

 or exude small quantities of matter in 

 a manner and with a purpose not 

 satisfactorily ascertained. 

 Ro'eidds — Dewy ; covered with little 

 transparent elevations of the paren- 

 chyma which have the appearance of 

 - fine drops of dew. 

 KoSe-bcshbs, To Desteot Aphides on — 

 See "Aphides." 



Eose'us — Rose-coloured ; pale red. 



Ro'TATE, RoTA'CEUS, EoTiEFOE'MIS, RoTIf'- 



OEMis, RoTATDS— When a mono- 

 petalous corolla has a very short tube 

 and spreading limbs, thus supposed to 

 resemble a wheel. The corolla of the 

 common Pimpernel, Anagallis arvensis, 

 is rotate. 

 Rostel'lum — A term applied to a process 

 which intervenes between the anther 

 and stigma of an Orchid flower, and 

 which has been aptly termed the floor 

 of the former and the roof of the latter. 

 Rosteha'ths— Furnished with a stiff and 

 often somewhat honked termination, 

 supposed to resemble a little beak. 

 Eostka'lus — Beaked. Ro'steum— A 

 beak. (See fiower-buds and fruit of 

 Eucalyptus rostrata, a tree very 

 abundant along the Condamine River.) 

 Rota'tion, Rota'tio— The internal circula- 

 tion of fluids in the cells of plants. 

 Rotation Ckopping should be carried out 

 as far as possible both in farm and 

 garden. In changing crops it is best 

 to avoid planting any to succeed others 

 which are nearly allied. Thus it will 

 be found advantageous for Cabbage, 

 Turnips, &c., to follow Beans, Peas, 

 Onions, &o. Peas have been found to 

 do well when planted after Celery. 

 An American writer says — Pirst year, 

 Cabbage ; second year. Onions ; third 

 year, Carrots, Beets, or Parsnips ; 

 fourth year. Potatoes or Turnips ; fifth. 

 Celery, Spinach, or Lettuce. No doubt 

 this system could be advantageously 

 applied to fruit-growing in the orchard, 

 &c., by allowing the land to be occu- 

 pied by one kind of fruit but for a few 

 years, when the trees should all be 

 destroyed and as dissimilar as possible 

 a kind planted in their place. The time 

 allowed to each sort of fruit would vary 

 according to kind. This mode would 

 be particularly advantageous where the 

 subsoil was sour or otherwise bad. 

 RoTnNDA'Tns — Roundish. Rotun'dds — 

 Round ; synonym for " Orbicularis." 

 (See PhehaUum rotundifohum. ) 

 Rubel'lus — Somewhat red. RuBBS'OENS — 

 Growing red. Ru'bens — Red. EuBl- 

 cnN'DUS — Ruddy. Ru'bee — Pure red 

 of a deep tint. Ru'tilans, "Ru'tilus 

 (Fiery red) — Of a brick-red colour ; red, 

 with a moderate i-ortion of grey, also 

 glittering with red. 

 Rubico'lus — Parasitic on, or attached to, 



the steins or leaves of a Bubus. 

 Rubigin'bds, RnBlGiNO'sus — Rusty; of a 

 brownish red tint; red, with much 

 grey. _ Eupescens, Rufus — Brown 

 inclining to red. 

 Rudeea'lis — Growing in waste places, or 

 among rubbish. Example, the common 

 weed, Lepidium ruderale. 

 Ru'dimentabt — Either in an early stage of 

 development, or in an imperfectly 

 developed condition. 

 Rd'qa- a wrinkle. Rugose', Rdgo'sula, 

 RuGo'sus— Rough, wrinkled. Rtiou- 

 LO'sus — Where a surface is covered 

 with wrinkles. (See the leaves of the 

 common Sage plant. ) 



