62 
ANNE M. LUTZ 
beyond doubt, to have 15 chromosomes, 2 quite distinct types had 
I5(?) chromosomes (number not determined precisely). 
We may now consider, briefly, the evidence furnished by these 15- 
and i5(?)-chromosome forms. 
(a) Distinct Types Having 15 Chromosomes. — Four of the 1 1 distinct 
types are very common Lamarckiana mutants, though found in other 
cultures, as well: (i) 0. lata, (2) 0. alhida, (3) 0. bipartita (C.S.H.) 
and (4) type 5509 (C.S.H.) , supposed to be a modified form of de 
Vries's ohlonga. Among the less common forms are (5) O. nanella 
lata,^^ obtained from de Vries's culture of 0. lata X 0. Lamarckiana 
(1912), but found also in cultures of 0. Lamarckiana, 0. nanella, etc. 
(6) 0. subovata, obtained from 0. lata X 0. Lamarckiana, but also 
produced by 0. Lamarckiana, (7) A dwarf mutant, type 2256, found 
in a culture of 0. nanella, (8) type 4499, produced by 0. lata, selfed, 
and 0. lata X 0. Lamarckiana; and three mutants which have been 
observed in lata cultures only, thus far: (9) 0, exilis, (10) 0. exundans 
and (11) type 5365. 
0. bipartita is a remarkably beautiful and interesting form. The 
peculiarities of the young plant not yet come to flower are shown in 
Figure i. The leaves, particularly those of the young plants, are 
thin and papery feeling; those of the adult form being more crinkled 
and more finely crinkled, being somewhat broader in proportion to 
their length, than Lamarckiana leaves. Although bipartita attains 
the height of the tallest Lamarckiana, it is more dainty in appearance 
than the parental form (Fig. 2). Like the latter, it produces a circlet 
of basal branches which are somewhat shorter and less decumbent than 
the rosette branches of Lamarckiana (Fig. 3). Not only are the 
branches more slender, but the buds, which are regular and tapering, 
are shorter and the flowers smaller than in the case of Lamarckiana. 
0. bipartita is distinguished by the large number of flowers pro- 
duced having more than 4 regular, tapering, stigmatic rays. Flowers 
with 4H--rayed stigmas are common to most forms, yet the number of 
flowers produced daily by bipartita having 4+ -rayed stigmas forms a 
higher percentage of the total than has been found to be true of any 
other one of the freely blooming plants. The percentage of flowers 
having 4+ -rayed stigmas varies greatly among the individuals 
of a given type. Daily records were made during the greater part of a 
1^ Professor de Vries states that he uses the term "0. lata nanella'' and " 0. 
nanella lata " interchangeably. 
