2980 



RONDELETIA 



ROOT- GALLS 



A. F Is. red. 



odorata, Jacq. (R. speciosa, Lodd.)- Lvs. ovate, 

 nearly sessile: clusters 10-30-fld. : fls. crimson to brick- 

 red, with a conspicuous yellow throat; lobes elliptical 

 to roundish. Cuba, Mex. B. 2:53. B.M. 3953. B.R. 

 1905. F.C. 1:36. L.B.C. 19:1893. P.M. 2:242; 16:354. 

 R.H. 1891:522 (throat not conspicuously yellow). 

 G.W. 6, p. 125. Var. major, Hort., is a form with 

 larger fls. 



AA. Fls. pink to white. 

 B. Base of Ivs. more or less cordate. 



cordata, Benth. (Rogiera corddta, Planch. R. thyrsi- 

 flora, Hort., not Roth). Fig. 3427. Lvs. ovate, acumi- 

 nate, cordate: generally said to have pink or flesh- 

 colored fls. with a yellow throat (as in F.S. 8:754), 

 but in R.H. 1878:230 they are shown as pure white. 

 B.M. 8540. J.F. 2:122. Guatemala. Possibly also 

 native in Mex. 



latifolia, Hort. (Rogiera latifolia, Decne.). Lvs. large, 

 heart-shaped, acuminate, short-petioled: fls. in corym- 

 bose cymes, the tubes pink, the limb white; calyx-lobes 

 oval, obtuse. Guatemala. R.H. 1853:121. 



BB. Base of Ivs. not cordate, 

 c. Corolla-lobes ovate: stipules broadly ovate. 

 amdena, Hemsl. (Rogiera amcena, Planch.). Lvs. 

 elliptic, broader than in R. gratissima, and shorter, 

 acuminate, 2-5 in. long: fls. rose-pink, with a conspicu- 

 ous yellow throat. Guatemala. F.S. 5:442. Intro, in 

 Calif. See also R. versicolor, in suppl. list below 



cc. Corolla-lobes obcordate: stipules subulate. 

 gratissima, Hemsl. (Rogiera gratissima, Lind.). Lvs. 

 oblong-elliptic, 1-2 in. long, short-petioled, mostly 

 rounded at the base: fls. with a bright rosy tube, the 

 lobes fading from pale rose to whitish; throat not con- 

 spicuously yellow. Trop. Amer. I.H. 28:424. F.S. 

 15:1570 (corolla-lobes often obovate; stipules narrowly 

 ovate). Gt. 490 (as Rogiera elegantissima). J.H. III. 

 52:365. 



AAA. Fls. blue. (Hindsia.) 



longiflora, Cham. (Hindsia longiflora, Benth.). Lvs. 

 opposite, entire, lanceolate, more or less oval or some- 

 times almost linear, petiole very short, attenuate at the 

 base: infl. terminal corymb; fls. blue; calyx-tube short, 

 lobes linear; corolla-tube very long; segms. of lip oval, 

 spreading and acuminate. R.H. 1858, p. 329. H.U. 

 4, p. 243. This is now placed in the genus Hindsia, 

 which differs from Rondeletia in general appearance 

 and in the form of the corolla which is rather funnel- 

 shaped than salver-shaped, without any callous con- 

 traction or beard at the mouth of the tube and by the 

 caps, which is differently dehiscent. A second species of 

 Hindsia is H. violacea, Benth., from Brazil. B.R. 30:40. 



The following species have been occasionally cult.: R. americdna, 

 Linn. White-fid. W. Indies and S. Amer. B. anomala, Hort., is 

 an imperfectly known species said to have the Ivs. in 3's, and coral- 

 red or deep scarlet fls. with a presumably yellow throat. Habitat 

 _(?). R. Bdckhousii, Hook., a pink-fld. species from Trop. Amer., 

 is easily distinguished from those mentioned above by the 

 much longer calyx-lobes, which are pink. B.M. 6290. R. Piirdiei, 

 Hook., a beautiful pale yellow-fid, species from Colombia, has a 

 great pyramidal cluster 5 in. across and 4 in. deep, with an astonish- 

 ing number of fls., perhaps 150-200 in B.M. 5669. R. versicolor, 

 Hook. (Rogiera versicolor, Lindl. & Paxt.), is referred to R. amoena 

 by Index Kewensis but seems distinct. The fls. are said to be 

 'remarkable for their play of colors: the tube is yellow; the limb in 

 bud deep rose-color, changing when they expand to pale rose and 

 then to white, with a yellow disk, and having a 2-lobed green spot 

 in the center from the color of the stigmas, which protrude a little 

 beyond the mouth." B.M. 4579. J.F. 2: 112. 



F. TRACY HUBBARD.! 



ROOT-GALLS. Abnormal enlargements often appear 

 on the roots of plants. These enlargements are much 

 more frequent than is generally supposed, but from their 

 position under ground are rarely observed. From an 

 economic standpoint they have not received the atten- 

 tion that they merit. 



Although the term root-gall is usually applied to the 

 abnormal enlargement of roots due to insects and other 

 animal organisms, it has a much w r ider application as 

 used by most plant-growers. The presence of nodules 

 or local enlargements on the roots of plants has been 

 discussed by different authors under the names root- 

 galls, root-knots, root-swellings, and the like. In cases 

 in which the cause of the nodules of hypertrophied tissue 

 is known, special names have been assigned to the 

 enlargements. Thus the gall formed by the eel-worm 

 (Heterodera radicicola) is known as the nematode root- 

 gall (Fig. 3428); the enlargement on the roots of cab- 

 bage and related plants by the myxomycete (Plas- 

 modiophora Brassicse) is called club-root; the swellings 

 on the roots of the peach, apricot, and many other plants, 

 which are of characteristic appearance and usually 

 appear at the crown of the plant, are known as crown- 

 gall. Root-tubercles are small gall-like bodies found on 

 the roots of many leguminous plants. They are sym- 

 bionic in nature, the organism causing them being 

 helpful to the plant. See Legumes. 



Abnormal root enlargements are due to the follow- 

 ing causes: (1) animal parasites, as in the nematode 

 root-gall (Fig 3428), the galls formed on the roots of 



the grape by 

 the phylloxera, 

 woolly aphis 

 galls on apple 

 tree roots, and 

 the like; (2) 

 vegetable para- 

 sites, as in the 

 club-root and 

 the crown - gall 

 (Fig. 3429); (3) 

 mechanical in- 



3428. Root-galls due to nematodes. 

 Tomato roots. 



ury, causng ex- 

 cessive callous 

 development, 

 root -burls, and 

 so on. In addi- 

 tion to these the 

 '7 causes of these 

 enlargements 

 are oftentimes 

 obscure or un- 

 known. 



Swellings on 

 the roots of the 

 mulberry are 

 said to be due 

 to the hypertrophy of the lenticels. Some investigators 

 have attributed gall-like root-growths in some instances 

 to the hypertrophy of adventitious buds. 



The root-galls caused by the nematode (Heterodera 

 radicicola) may usually be readily recognized from 

 other forms of hypertrophied tissue by the numerous 

 knotty enlargements on the smaller roots infested by 

 the worms. By careful search, in most instances, the 

 distended female worms may be found in the infested 

 tissue, where they appear as small nearly spherical 

 pearl-like bodies, readily seen with the unaided eye. 

 This minute worm, commonly called eel-worm, feeds 

 upon the roots of a great variety of cultivated plants and 

 is particularly destructive in the South. It is usually 

 injurious in the northern states only to plants growing 

 under glass. However, ginseng and some other outdoor 

 perennials often suffer severely as far north as Michigan 

 and southern Canada. The most effective remedy in 

 the case of field crops is the removal of all rubbish that 

 would harbor the worms during the winter. In green- 

 houses steam can be forced through the infested soil. 

 When potted plants are badly affected, they may be 

 severely root-pruned and repotted in soil free from 

 worms. 



The root-swellings caused by the grape-vine gall- 



