and Laboratory Methods. 1899 



CURRENT BOTANICAL LITERATURE. 



CHARLES J. CHAMBERLAIN, University of Chicago. 



Books for Review and Separates of Papers on Botanical Subjects should be Sent to Charles J. 

 Chamberlain, University of Chicago, Chicago, 111. 



Lloyd, F. E. The Comparative Embryology of This paper is based upon a Study of 

 the Rubiaceae. Memoirs of the Torrey Bot. 23 species representing 9 genera of the 



Club. 8:27-112. Pis. 5-15, IQ02. -n t-- T 1 -^ u -J 



•^ -^ ^ Rubiaceae. In general it may be said 



that the archesporial tissue in the nucellus is quite extensive, consisting of from 

 seven to fifteen cells, but according to the author, the pleuricellular archesporium 

 is not a primitive character and has no phylogenetic significance. The mega- 

 spore mother cells divide twice, giving rise to a row of four potential megaspores, 

 except when the development is arrested. Sometimes the nuclear divisions oc- 

 cur, but no walls separating the potential megaspores are formed. In the first 

 division of the megaspore mother cell the spindle is multipolar and no centro- 

 somes are to be found. In Cnccianella and Asperula, where the cytological 

 features were carefully studied, the reduced number of chromosomes is 10 and 12 

 respectively, but, after counting in a large number of cases, the writer believes 

 that the number of chromosomes is not constant. In Asperula,'va. a late anaphase 

 of the first division, the second longitudinal splitting of the chromosomes is 

 already quite evident. In Crucianella this splitting takes place in the telaphase. 

 The divisions giving rise to a row of four potential megaspores, judged from a 

 cytological standpoint, are true tetrad divisions. 



The embryo-sac sometimes develops in situ, but sometimes passes out into 

 the micropyle, moving like a pollen tube. In the Galiece the lowest of the three 

 antipodals becomes very long and is plunged among the mass of disintegrating 

 megaspores, which it absorbs. In Diodia a row of from four to ten antipodals 

 serves the same purpose as the single long cell. 



The suspensor development is quite remarkable. Lateral outgro^\i:hs pene- 

 trate the endosperm and act as haustoria, the nutritive function being even more 

 highly developed than in the Leguminosae. c. j. c. 



Frye, T. C. Development of the Pollen in This paper, which was already going 

 some Asclepiadaceae. Bot. Gaz. 32: 325- to press when Strasburger's work on 

 33 > P • 3> 9 • ^i-^/^/rt'j appeared, is in perfect accord 



with Strasburger's results as far as the most important question is concerned, 

 viz., that in Asclepias the mother cell gives rise to four microspores as in other 

 flowering plants. The mother cell is recognized by the reduction of chromo- 

 somes and the character of the mitotic figure. A most complete series was 

 studied in A. tuberosa, but A. Cormiti, A. phytolaccoides, A. ijicarnata, A. verticil- 

 lata, and also Acerates viridiflora and A. longifolia were studied sufficiently to 

 warrant the conclusion that the development of the pollen is essentially the 

 same in all. 



The deeply staining granules described by Strasburger were observed by 



