GENUS MARANTA. 



829 



Second, when fissures of a similar character are present they are more sharply defined, but frequently 

 very irregularly arranged clefts appear, which have no connection with the hilum. Third, the starch 

 is often broken into many rather large, irregularly arranged, refractive fragments by means of the 

 clefts above mentioned, and gelatinization in many grains does not advance beyond this stage. 

 Fourth, the lamellae throughout the grain are more resistant and, when disorganized, more brilliant, 

 refractive granules appear, many having a linear arrangement. The gelatinized grains are much 

 swollen and some retain the general shape of the untreated grain, while more of the ungelatinized 

 starch is often present than in M. arundinacea, which appears to cause some distortion of the grain. 



Differentiation of Certain Starches of the Genus Maranta. 



HisToiiOaicAL Characteristics. 

 Conspicuous Forms. 



M. arundinacea: Usually simple, few aggregates and com- 

 pounds, pressure facets rare, usually regular, irregu- 

 larities due to depressions or to rounded, pointed, 

 cone-shaped or nipple-like protuberances; ovoid, 

 ellipsoidal, pyriform, triangular, nearly round, 

 mussel-shell-shaped, ellipsoidal with central eleva- 

 tion at the side. Somewhat flattened. 



M. arundinacea var. No. 1: Usually simple, rare com- 

 pounds, no aggregates, pressure facets rare, gener- 

 ally irregular. Ovoid to oval and elliptical, clam- 

 shell-shaped, mussel-shell-shaped, triangular with 

 rounded angles, spherical. 



M. arundinacea var. No. 2: Usually simple, few com- 

 pounds, no aggregates, pressure facets rare, usuidly 

 irregular. Ovoid to oval and elliptical; also clam- 

 shell-shaped, mussel-shell-shaped, pyriform, trian- 

 gular, spherical, dome-shaped. 



M. massangeana: Simple, no compounds, many aggregates, 

 pressure facets common, generally regular. Dome- 

 shaped, round, polygonal. 



M. leuconeura: Usually simple, rare compounds and ag- 

 gregates, pressure facets common, usually regular. 

 Dome-shaped, round, polygonal. 



Af. musaica: Usually simple, few aggregates and com- 

 pounds, pressure facets occasional. Irregular pyri- 

 form, triangular,clam-shell-shaped,elongated ovoid, 

 and elUpsoidal. 



Hilum — Form, Number, and Position. 



M, arundinacea: Form clear, round or lenticular spot; 

 small round cavity or one or more fissures may 

 be present. Position usually eccentric about 0.33 

 to 0.25 of longitudinal axis. 



Af. amndinaceavar.No.l: Form small, round, non-refrac- 

 tive; sometimes fissured. Position nearly eccentric 

 about 0.16 to 0.25 of longitudinal axis. 



Af. arundinacea vai. No. S: Form distinct, relatively large, 

 round, refractive; double hila common; often fis- 

 sured. Position usually eccentric about 0.16 to 0.25 

 of longitudinal axis. 



M. massangeana: Form round, clear, refractive spot; usu- 

 ally not fissured. Position usually eccentric about 

 0.40 to 0.42 of longitudinal axis. 



M. leuconeura: Form round, clear spot; usually not fis- 

 sured. Position usually eccentric from 0.46 to 0.16 

 of longitudinal axis. 



Af . musaica: Form frequently not demonstrable, clear, 

 round, non-refractive spot; rarely fissured. Posi- 

 tion usually eccentric about 0.16 to 0.11 of longi- 

 tudinal axis. 



Lamellw— General Characteristics and Number. 

 M. arundinacea: Fine, less fine near the hilum than near 



the distal end; complete rings near hilum, but have 



shape of margin peripherally. 28 to 32 on larger 



grains. 

 Af. arundinacea var. No. 1: Usually not very distinct, 



rather coarse, continuous circles or arcs of circles; 



vary in size and spacing in different grains. About 



23 on larger grains. 



HisTOLOQicAL CHARACTERISTICS. — Continued. 



Lamellae — General Characteristics and Number. — Cont'd. 



M. arundinacea var. No. 2; Not very distinct circles or 

 arcs of circles; these marginally follow outline of 

 grain; two sets where double hila are present. 

 About 38 on large grains. 



Af . massangeana: Fine, complete circular rings in round 

 grains; have form of grains in dome-shaped grains. 

 About 8 to 16. 



Af. leuconeura: Not demonstrable in small dome-shaped 

 and round grains; distinct and delicate in large 

 ovoid, triangular, and shell-shaped grains. About 

 32 on large ovoid and 20 to 26 on rounded triangu- 

 lar and shell-shaped. 



Af . musaica: Quite distinct, circular rings near hilum, but 

 follow outhne of grain when distal; secondary sets 

 of lamellae common; mostly fine. About 28 to 32 

 on the large grains. 



Size. 



M. arundinacea: From 3 to 36;i, commonly 24/i. 



M. arundinacea var. No. 1: From 11 to 54/j, commonly 



20m. 

 Af . arundinacea var. No. 2: From 7 to 64;i, commonly 



28m. 

 Af . massangeana: From 4 to 26m, commonly 16m. 

 Af . leuconeura: From 2 to 30m, commonly 22m. 

 Af . musaica: From 4 to 36m, commonly 26m. 



POLARISCOPIC PrOPERTXEB. 



Figure. 



M. arundinacea: Quite eccentric to slightly eccentric 

 and centric; lines distinct, fine, and intersect 

 obliquely; generally straight; sometimes bent or 

 bisected. 



M. arundinacea var. No. 1: Usually eccentric, distinct, 

 clear-cut; lines usually well defined and compara- 

 tively narrow; may be bent or otherwise distorted 

 and placed at varying angles. 



Af. arundinacea var. No. 2: Usually eccentric, distinct; 

 lines very clearly defined; lines at varying angles. 



M. massangeana: Usually eccentric, distinct, lines rather 

 fine, usually straight and usually intersect at right 

 angles. 



M. leuconeura: Usually eccentric, distinct, lines rather fine 

 and usually straight, and usually intersect at right 

 angles. 



Af . musaica: Eccentric, usually distinct, lines rather fine 

 and intersect obliquely, frequently bent and some- 

 times bisected; more eccentric and more irregular 

 than in M. arundinacea. 



Degree of Polarization. 

 M. arundinacea: High, slightly variable in different grains 



and in same aspect of a given grain. 

 M. arundinacea var. No. 1: High, about the same as in 



M. arundiruuxa, but more variations. 

 Af . arundinacea var. No. 2: High, about the same aa in 



Af . arundinacea, but more variations. 

 Af . massangeana: High, about the same as in Af. arundi- 



naeea, but more variations. 



