786 



MACROSCOPIC AND MICROSCOPIC CHARACTERS OF PLANTS. 



thicker than the peduncles: sepals oblong, 7 mm. long, 

 apprcssccl to the tips with subulate iufraterminal awns 

 smaller than in /. cocciitca: corolla scarlet; tube 3 cm. 

 long, slightly enlarged above, shallow saucer-shaped limb 

 2 to 3 cm. broad, 5-angled: capsules ovoid, only a few 

 mature : seeds 1 to 2 in each capsule, very rarely 3 to -1 

 mature. 



ORIGIN OF I. SLOTEEI. 



A hybrid of /. coccinca and /. quamoclit was obtained 

 in 1897 by hand pollination by Mr. Logan Sloter, who 

 supplied the following data : 



" This vine was in degree of growth and vigor in no way 

 superior to its parents, if anything it was inferior to them. 

 Foliage long and narrow, pale green, and thin of texture; 

 lluwi-ra rotund and freely produced, but of a dull red hue and 

 but three-quarters inch in diameter. This specimen was abso- 

 lutely seedless. By repeating the original cross, 1 succeeded in 

 producing a few specimens of it up till 1908, with the same 

 result. But in 1908, one specimen produced one seed. This 

 one seed was planted in 1909, and from it grew the cardinal 

 climber as it appears to-day." 



Mr. Sloter tried in hundreds of instances to cross this 

 hybrid with other Ipomoeas, but without success, nor 

 could he succeed in crossing it with either of its parents. 

 Therefore, he believes that the plants used in this re- 

 search are first hybrids, the straight descendants from 

 that one seed planted in 1909. He states: 



" The cardinal climber is remarkably true from seed, the 

 deviations being small and few, and so nearly identical with 

 the parent as to be unnoticeable by the ordinary observer. For 

 the most part they consist of some specimens showing small 

 oculations or lighter places in the throat or opening of the tube, 

 while others show no such markings. Some plants may be a 

 ahade lighter or a shade darker in color than others. Aside 

 from this the cardinal climber has thrown off one specimen 

 bearing dark rose flowers and a specimen bearing orange-scarlet 

 flowers which come true from seed; also Iponura serratifolia, a 

 leaf variant, thrown off by the parent plant three seasons ago 

 (1910). /. serratifolia is identical with the cardinal climber 

 in every respect except foliage. Its foliage has more the appear- 

 ance of an uncut leaf with a toothed edge." 



Examinations of three plants of the cardinal climber 

 of the season of 1913, and eight plants of the season of 

 1914, all germinated from self-pollinated seed and grown 

 in the Botanical Gardens of the University of Pennsyl- 

 vania, showed that all were exactly alike, there being no 

 appreciable variation. 



Ipomcea sloteri has recently been described by Nieuw- 

 land (American Midland Naturalist, 1915, iv, 71). He 

 goes on to state : 



" Since the plant Quamoclit sloteri possesses characters 

 that are notable enough to make it seem specifically distinct 

 from either parent and from all of the members of the genus, 

 why should the knowledge of its ancestry militate against it as 

 deserving a 'species' name in binary nomenclature? With its 

 character of breeding true it deserves to be ranked as a new 

 plant as truly as the mutants or new species published under 

 Oenotlicra during the last decade. It is likely that many species, 

 unequivocably ranked as such found in the field, have fewer 

 characters of distinction than the plant in question." 



In reading over a description of Quamoclit muUifida 

 Eaf ., Nieuwland " was forcibly struck by the fact that the 

 characterization of this plant is practically identical with 

 that of the plant produced by Mr. Sloter." 



The following description is quoted from Rafinesque 

 (New Flora of North America, 1836, Part IV, 57) : 



"Quamoclit multifida, Eaf. Twining, smooth, leaves mul- 

 tifid, lacinate, base truncate, sinuses obtuse, segments linear 

 and lanceolate acute, peduncles 3-5 flors, equal to petioles, calix 



acute a curious sp. deemed a garden hybrid produced by Q. 

 coccinea and Q. pinnata, leaves variously cut few alike, some 

 reniform with shorter cuts, (lowers handsome, large purple, 

 tube clavate, limb Hat stellate pentagone, stamens exserted. 

 Seen alive in gardens, where sometimes spontaneous. The Q. 

 pinnata Kaf. above is certainly Ipomcea quamoclit Linn, the 

 only pinnate leaved Quamoclit known by him at the time." 



It should be noted that Xieuwlaud erroneously states 

 that the color of the flower of I. sloteri is the same as that 

 of /. coccinea. 



COMPARISONS OF THE MACROSCOPIC CHARACTERS. 



COTYLEDONS. 



The cotyledons of I. coccinea, I. quamoclit, and 7. 

 sloteri, from seedlings of exactly the same age, are illus- 

 trated in Plate 25, figs. 145, 148, 151. The hybrid shows 

 a mid-degree of intermediateness in the shape of the 

 cotyledons, and it is also very nearly mid-intermediate 

 in the length of the mid-rib and in the length of the 

 petiole. (Table J 1.) 



TABLE J 1. Lengths of midrib and petiole. 



Midrib: I. coccinea 1.3 cm.; I. quamoclit 0.3 cm.; I. sloteri 0.9 cm. 

 Petiole: I. coccinea 3 cm.; I. quamoclit 1.05 cm.; I. sloteri 2.3 cm. 



The cotyledons of I. coccinea have two blunt, rounded 

 lobes, with an angle of 90 between them; those of 7. 

 quamoclit have two narrow, tapering lobes, with an angle 

 of 150 ; those of the hybrid have two lobes which are 

 slightly narrower than those of 7. coccinca but much 

 wider than those of I. quamoclit, and with an angle of 

 120. The lobes of the hybrid taper more toward the 

 apices than those of 7. coccinea, but the apices are less 

 acute than those of 7. quamoclit. 



ROOTS. 



The primary root of 7. coccinea is rather thick, has a 

 diameter of 5 mm., is slightly flattened, and extends for 

 a distance of about 7 cm. below the surface before divid- 

 ing into two strong branches, before which division only 

 a few small side rootlets are given off. The primary root 

 of 7. quamoclit is about 2.5 mm. in diameter, very 

 slightly flattened, very long (19 cm.), and gives off only 

 a few thread-like side rootlets. The rootage of the hybrid 

 is much more extensive than in either parent. The pri- 

 mary root is thick, 10 mm. in diameter, and extends 

 below the surface for a distance of 8 cm. before it divides 

 into 2 or 3 strong branches. Above the point of division 

 lateral rootlets arise which are long and branching and 

 spread out a good distance just below the surface of 

 the soil. 



STEM. 



The stems of all three plants are slender, climbing, 

 and give off many branches. The stem of the hybrid has 

 a greater diameter, attains a greater growth, and gives 

 off many more branches than in either parent, in these 

 respects being nearer to 7. coccinca than to the other 

 parent. The stems are in all cases flattened, one diameter 

 being about half that of the other. 



The diameters of the stem for 7. coccinea are 5 by 

 3.5 mm.; for 7. quamoclit 1.3 by 0.9 mm.; for 7. sloteri 

 8.7 by 4.6 mm. 



The stems of the parents and the hybrid branch at 

 different distances above the ground : 7. coccinea branches 

 nearest the ground 4.2 cm. ; 7. quamoclit, a good dis- 

 tance above 7.1 cm. ; and the hybrid, at a point between 

 the two 6 cm. 



