822 



STARCHES OP MARANTACE^. 



With ferric chloride a beginning of a reaction is seen in some grains at once. A few are gelat- 

 inized in a minute, about four-fifths in 5 minutes, nearly all in 10 minutes, all but rare resistant 

 grains in 15 minutes, and all in 25 to 30 minutes. The lamellae disappear and the hilum becomes 

 distinct as a black spot. There is often a protrusion or gelatinization of the margin at the nodules 

 or nipple-Uke processes of the grain or from the distal end. The rest of the margin becomes clear 

 and shows lamellation, and a ring is formed which widens as it spreads inward, lessening the area 

 of the inner, lighter portion. The swelling is slight until a bubble is formed at the hilum. This is 

 followed by great swelling and the disappearance of the bubble. By this swelling a clear inner 

 space is formed, surrounded by a darker portion that exhibits striated rings, and granular masses 

 are present where protrusion first took place from the margin. The gelatinized grains gradually 

 become clear and are finally quite transparent. They are very large, oval, and somewhat folded 

 and crumpled. 



Swelling begins in 30 seconds or less with Purdy's solution. A few grains are gelatinized in a 

 minute, about one-fourth in 5 minutes, about two-thirds in 30 minutes, and four-fifths in 60 min- 

 utes. The hilum and lamellae become more distinct. Two refractive lines extend from the hilum to the 

 margin, and the grain becomes finely striated. The hilum and the grain swell very rapidly, form- 

 ing a smooth, gelatinized grain which has a distal end with a lobulated outline, and a collection of 

 granular starch. The margin is darker than other parts of the grain, and shows one or three finely 

 striated darker bands, which gradually disappear, as does the granular mass at the lobulated distal 

 end. There is no essential difference in the gelatinization of grains with fissured hilum. The gelat- 

 inized grains finally formed are very large and of a regular, rounded, ovoid outline. 



STARCH OF MARANTA MASSANGEANA. (Plate 89, figs. 529 and 530. Chart 348.) 



Histological Characteristics. — In form the grains are simple and consist of isolated ones which 

 were the components of small aggregates, with the exception of a small number which have never 

 existed as aggregates and a few small aggregates. No compound grains were observed. Pressure 

 facets are found on most of the grains. The grains are generally regular, but a slight concave in- 

 dentation, possibly a pressure facet, may be found at one 

 side of the distal margin of the larger, rounded grains 

 which have a broadened and somewhat thinned distal 

 margin. The conspicuous forms are dome-shaped with 

 squared or pointed base, round, and polygonal. There 

 are also a few ellipsoidal and rounded with broadened 

 and somewhat thinned distal end which approach the 

 triangular with rounded angles. Scattered among the 

 numerous separated grains are much larger ones which 

 are gelatinized and so distorted that their structure can 

 not be studied. The grains are more regular than those 

 of M. arundinacea, differ generally in shape, and in the 

 frequent presence of pressure facets. 



The hilum is a round, clear, refractive spot, centric 

 to slightly eccentric about two-fifths to five-twelfths of 

 the longitudinal axis. The hilum is usually not fissured. 

 Clefts which form either a stellate, a Y-shaped, or a 

 soaring-bird figure are sometimes present. 



The la?nellce are demonstrable, and in the round 

 forms of large size from 12 to 16 rather fine, complete, 



circular rings may be counted. In the dome-shaped type the lamellae, even those immediately around 

 the hilum, usually have the form of the grain. There are 8 to 10 lamelliE on the large, dome-shaped 

 grains. They are more often demonstrable throughout the entire grain than in M. arundinacea. 



The grains vary in size; the smaller are 4 by 3ii; the larger, dome-shaped grains are 24 by 20^, 

 and the large, round forms are 26 by 26m in length and breadth. The common size of the dome- 

 shaped grains is about 18 by 16^ and of the round grains about 16 by 16^ in length and breadth. 



Polariscopic Properties.— The figure is centric to slightly eccentric, rarely quite eccentric, dis- 

 tinct, and clear-cut. Its lines are rather fine and usually straight; they often cross at right angles, 

 but sometimes obliquely. The figure is more regular than in M. arundinacea. 



Oiari No. 348. 



PC PS 

 5 



Curve of Reaction-Intensities of Starch of Maranta 

 massangeana. 



