C YMBIDIUM CALANTHE . 



769 



The hilum and lamellae are as distinct as in C. lowi- 

 anum, and gelatinization begins at the hilum as in both 

 parents, and the process is the same as described under 

 C. lowianum, except that the granules formed of the 

 starch immediately surrounding the hilum are not so 



numerous as in those grains. The gelatinized grains are 

 large and as distorted as those of C. lowianum. In this 

 reaction C. elurneo-lowianum shows qualitatively a 

 slightly closer relationship to C. lowianum than to C. 

 eburneum.- 



17. CALANTHE. 



This genus of sub-epiphytal or terrestrial orchids in- 

 cludes a few species, and there are a number of varieties 

 and hybrids. Starches from the pseudobulbs of the fol- 

 lowing parent-stocks and hybrid-stocks were studied: 



45. C. rosea (seed parent), C. vestita var. rubro-oculata Hort. 



(pollen parent), and C. veitchii Lindl. (hybrid). 



46. G. vestita var. rubro-oculata, Hort. (seed parent), C. 

 regnieri (C. vestita var. regnieri var. williamsii) (pollen 

 parent), and C. bryan (hybrid). 



The specimens were obtained from James Veitch and 

 Sons, London, England. 



45. STARCHES OF CALANTHE ROSEA, C. VESTITA VAE. 

 RUBKO-OCULATA, AND C. VEITCIIII. 



CALANTHE ROSEA (SEED PARENT). 



(Charts D 019 to D 626.) 

 HISTOLOGIC PKOPEBTIES.* 



In form most of the grains appear to be simple (as 

 the hilum is rarely demonstrable it can not be definitely 

 asserted) and are isolated with the exception of a few 

 which appear in aggregates, usually of 2 components. 

 Definite compound and semi-compound grains consisting 

 of from 2 to 4 components are rarely observed. No well- 

 defined pressure facets are observed, although flattening 

 either at one end at indefinite points as well as small 

 concave depressions are found. The surface of the grain 

 is generally irregular, which is chiefly due to the fol- 

 lowing causes: A sinuous to crenate outline, the latter 

 frequently at one end ; a difference in the contour of the 

 sides; shifting of the longitudinal axis, sometimes result- 

 ing either in one or two abrupt curves ; small nipple-like 

 to large protuberances at the proximal end ; a protuber- 

 ance apparently at the distal end, but since a hilum is 

 rarely distinguishable in these grains a definite orienta- 

 tion is difficult; deep concave indentations at varied 

 points more frequently appear to be at the distal end; 

 and occasionally moderately large blunt protuberances 



at one side which probably represent a secondary growth. 

 The conspicuous forms are almost round; rounded tri- 

 angular; ellipsoidal, sometimes with slightly broadened 

 and squared diagonal or irregular distal end; pyrifonn 

 squared at the narrow end; shield-shaped and rhom- 

 boidal. The additional forms are perfect ovoid; lenticu- 

 lar; reniform, scroll-shaped, dome-shaped, probably a 

 separated grain, and grains of indefinite form. Most 

 of the grains are very much flattened and when viewed 

 on edge are either narrow lenticular or rod-shape. 



The hilum is rarely demonstrable, when made out 

 it appears as a small non-refractive spot which varies from 

 centric to quite eccentric, commonly eccentric. Either 

 a small crescentic or lenticular transverse cleft at the 

 hilum, and delicate definite fissures leaving it are rarely 

 observed. The longitudinal fissures appear either as one 

 from each side of the hilum passing obliquely towards 

 the distal margin, or as one median straight, curved or 

 diagonal, which is generally clean-cut, though sometimes 

 either ragged throughout or branched at the distal end. 

 The main body of most of the grains is broken either into 

 refractive masses or granules by irregular translucent 

 branched lines having no connection with the hilum, 

 sometimes the branching being so numerous as to form a 

 network, or the main body may be studded with trans- 

 lucent dots which impart a pitted appearance to this 

 region of the grain. It is uncertain whether these lines 

 are fissures, or whether both lines and dots are related 

 to the inequalities of the surface, and thus simply indicate 

 differences in density. When deeply pitted or divided 

 by a network of lines so as to break the body into granules 

 the grains have the appearance of partial gelatinization. 

 The position of the hilum is centric to quite eccentric, 

 the range of eccentricity varies from 0.33 to 0.1, more 

 frequently about 0.2 of the longitudinal axis. Since the 

 hilum is rarely demonstrable these figures are only 

 provisional. 



* It is difficult to obtain the percentage of gelatinization 

 with Calanthe rosea, 0. veitchii, and C. regnieri. These starch 

 grains are mixed with numerous oxalate needles, G. regnieri 

 having the greatest numl>er. When a thin layer of the prepa- 

 ration is made on the slide it is frequently found to contain 

 but a small proportion of starch grains. It is almost impos- 

 sible to find 100 grains in the field under the high power of the 

 polariscope, and the grains are so small that the process of 

 gelatinization can not be satisfactorily studied under the low 

 powers. It is difficult to obtain more than 40 or 50 grains in 

 the field when working with C. regnieri, in such an event it 

 is necessary to repeat the experiment several times in order 

 to eliminate the chance of error. The degree of polarization of 

 the three starches mentioned is low except in the narrow 

 marginal border and, when viewed on edge, the needles are so 

 brilliant and so massed when observed under the polariscope 

 that it is almost impossible to obtain the percentages by means 

 of the polariscope unless the reagent used dissolves these 

 needles; and therefore the results have to be obtained by means 

 of the miscroscope and the polariscope combined, if the latter 

 is at all possible. Most of the grains of the Calanthe in the 

 specimens studied have much the appearance of partial gel- 



atinization, and when studied with iodine the reactions are 

 very reddish in tint, resembling the reaction with dextrin; the 

 Calanthe regnieri is the farthest removed from the character- 

 istic color reaction of starch with iodine. 



These grains are much flattened and often present a pitted 

 appearance, notably in C. regnieri; this may be due to partial 

 gelatinization, but as the margin is usually wavy and sometimes 

 even scalloped it might be due to different densities caused by 

 these elevations. 



The Calanthe vestita var. rubro-oculata is quite normal in 

 appearance, the C. bryan being more nearly normal than in the 

 three starches mentioned. This hybrid has marked character- 

 istics of both parents, and this fact seems to indicate that the 

 C. regnieri grains as noted may be the normal grain for this 

 species. If the C. regnieri is a grain of great instability which 

 is readily partially gelatinized, then C. bryan inherits this 

 characteristic. 



The narrow marginal layer of the species C. rosea, C. 

 veitchii, and C. regnieri is very resistant to most reagents, 

 especially at the proximal end and sides nearby. These layers 

 in the untreated grain may extend around the entire grain or 

 only appear at the proximal end and sides nearby. 



