FARR: QUADRIPARTITION IN SISYRINCHIUM 59 
ing on the other hand takes place only after a considerable time 
has elasped following the re-formation of the nuclei. If cell- 
plates appeared in this division we would most certainly expect 
to find them in such an anther as that shown in FIG. 2, but none 
such are present. 
The process of cytokinesis in the quadripartition of the 
pollen-mother-cells of Sisyrinchium is by furrowing and is 
practically identical with that found in Nicotiana. It does not 
seem necessary to repeat the details of the description of the 
process here, inasmuch as there is no difference from that which 
has been published before (4). In cells where the nuclei are 
tetrahedrally arranged the plasma membrane invaginates most 
rapidly at the points equidistant from the three nuclei and 
therefore a central triangular area is formed (Fic. 3). In cells 
in which the nuclei are in one plane no such central triangular 
area appears, but the spindles have the same relation to each 
other, as was shown in those cells of Magnolia (5) in which the 
arrangement was of this type. 
LITERATURE CITED 
1. D’Angremond, A. Parthenokarpie und Samenbildung be 
Bananen. Flora 107: 57-110. pl. 4-11. 5. 
. Brongniart, Adolph. Mémoire sur la génération et le dé- 
veloppement de l’embryon de la végétaux phanérogames. 
Ann. Sci. Nat. 12: 14-53, 145-172, 225-296. fl. 34-44. 
1827. 
. Digby, L. On the archesporial and meiotic mitoses of 
Osmunda. Ann. Bot. 33: 135-172. pl. 812. 1919. 
Farr, C. H. Cytokinesis of the pollen-mother-cells of certain 
’ Dicotyledons. Mem. New York Bot. Garden 6: 253- 
217. Dl. 27-29. IGIG. 
- — Cell division by furrowing in Magnolia. Am. Jour. 
Bot. 5: 379-395. pl. 30-32. 
. Farr, Wanda K. Cell division of the pollen-mother-cells of 
Cobaea scandens alba. Bull. Torrey Club 47: 325-338. 
pl. 14. 1920. n 
Florin, R. Cytologische Bryophytenstudien I. Uber Spor- 
enbildung bei Chiloscyphus polyanthus (L.) Corda. 
Ark. f6r Bot. 15'*: 1-10. pl.r+/f.1,2. 1918. 
. Frye, T. C., & Blodgett, E. B. Contribution to the life- 
history ‘il Apocynum androsaemtfolium. Bot. Gaz. 40; 
49-53. pl. 2. 1905. 
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