1291 
II. On the occurrence of pollengrains with 3 and more nuclei. 
ScnürnHorr (1919) has drawn our attention to the fact that among 
Monocotyledons as well as Dicotyledons pollengrains with 3 nuclei 
—1 vegatative and 2 generative — occurs before the germination. He 
wonders whether this early- division of the male sexual nucleus has 
a biological or a systematical importance and concludes on p. 147, 
after giving a general view of the orders of plants where pollen- 
grains with 3 nuclei have been noticed: “Es ergibt sich also aus 
dieser Aufstellung, dass dem Vorkommen von dreikernigen Pollen- 
körnern keine besondere systematische Bedeutung zukommt. Eine 
derartige Bedeutung liesze sich zur Not für die Monokotylen kon- 
struieren, da bei den ersten Ordnungen das Vorkommen dreikerniger 
Pollenkörner die Regel bildet, während sie bei den letzten Ordnun- 
gen der Monokotylen fehlen”’. Of the Monocotyledons, according to 
him, the Helobiae, the Glumiflorae and part of the Spadiciflorae 
are characterized by pollengrains with 3 nuclei. The orders of the 
Enantioblastae, the Liliflorae, the Scitamineae and the Gynandrae, 
with the exception of the Juncaceae and other isolated cases, do not 
possess them. 
If we examine more closely some cases of the Monocotyledons, 
we notice that ErrvinG saw, as early as 1878, 3 kernels in the 
pollengrains of Andropogon campesiris, and that SrraspurcEr (1884) 
saw that in many cases the generative nucleus was divided in the 
pollengrain. Gotinsky (1893) found 2 sperm-nuclei in the pollen- 
grains of Triticum, Scuarrner (1897) in Sagittaria variabilis. “The 
division of the generative nucleus before pollination”, he says on 
p. 254, “seems to be quite common in monocotyledons, and it is 
probable that this condition will be found to be the rule rather than 
the exception in this group’. According to the researches of CHAM- 
BERLAIN (1897) the generative nucleus of Liliwm aurantiacum and of 
Lilium tigrinum was divided in the pollengrain, “a condition not 
uncommon, in monocotyledons”, he says. In 2 cases he also observed 
in Zelium aurantiacum, that the divisions went still further, so that 
3 generative nuclei were present. In Lilium Philadelphicum the 
early division of the generative nucleus occured seldom. In Lilium 
martagon it is perhaps out of the question. GuigNarD (1891) at least 
notices that the generative nucleus is here only divided in the pollen- 
tube. The vegetative nucleus is never divided. In 1899 this naturalist 
saw 3 nuclei in the pollengrains of Najas major. Wineanp (1899) 
observed 2 generative nuclei in Potamageton foliosus Raf. and 
gives an enumeration of the cases at that time observed in Mono- 
8 3* 
