Volume 60, Issue 3
September 1964, pages 163-239
pp 163-166 September 1964
pp 167-170 September 1964
pp 171-188 September 1964
pp 189-195 September 1964
Thin stringers and lenslets of sulphide minerals replacing marbles along cracks and fissures are found around Chando (23° 58′ 36″ N, 84° 6′ 12″ E) in Palamau District, Bihar. Marbles and the paraschists represent the oldest rocks of the area. The marbles occur as more or less circular pockets within granite gneiss country. The minerals are mostly simple sulphides of Fe, Cu, Zn and Pb. The most abundant minerals are bornite and chalcopyrite. Two types of association are common—(a) chalcopyrite-bornite solid solution and (b) bornite-chalcocite solid solution. Myrmekite-like texture in bornite-chalcocite is noteworthy where chalcocite has largely replaced pyrite leaving behind minute remnants. In bornite, chalcopyrite has exsolved as blades along (111).
A mineral is detected which closely resembles ‘Orange Bornite’ (Orcel, 1937, 1943—supposed composition Cu5 FeS6) with yellowish orange colour and a higher reflectivity than bornite. It does not extinguish completely, but shows a greenish-pink colour and a mixed±reaction with KCN and HNO3.
The ore minerals show little or no secondary alterations. The source of the solution probably seems to be that from which the granite was derived and the solution might have supplied the metals along the fissures and cracks of the marble occurring within the granitic country. In course of replacement the sulphide solution produces beautiful ‘delta textures’.
pp 196-202 September 1964
1. The ovules ofParnassia nubicola are bitegmic and anatropous. They are tenuinucellate.
2. The megaspore mother cell generally forms a linear tetrad but T-shaped tetrads are also known to occur. Persistence of more than one healthy megaspore is also seen.
3. The embryo-sac isPolygonum-type. Enlargement of antipodals is a common feature. Their number may also increase sometimes.
pp 203-213 September 1964
In the normal seedling as well as in the syncotylous seedling, two pairs of medians are differentiated in the hypocotyl, while in the hemitricotyls and tricotyls there are differentiated three pairs of medians.
There is no connection between the root-hypocotyl-cotyledon system and the later formed epicotylar system in the early stages.
The differentiation of the procambial strands in the cotyledons is acropetal.
Unilateral syncotyly is of frequent occurrence inTagetes erecta and the anatomy of such abnormal cotyledons shows to a certain degree resemblance to the sheath of the monocotyledons.
In the abnormal seedlings there is a modification of the phyllotaxis and in cases where there is a reduction of the number of cotyledons, there is an associated reduction of foliage; thus, there exists a repercussion of cotyledonary anomalies.
pp 214-231 September 1964
pp 232-239 September 1964
1. The chromosome number ofCaesulia axillaris Roxb. has been determined for the first time as 2n=14 andn=7.
2. A haematoxylin squash technique has been adapted for application to meiotic cells.
3. One extra chromosome found in many meiotic metaphases is believed to be a supernumerary.
4. Structural changes of chromosomes such as reciprocal translocations and inversions have been recorded.
5. The basic chromosome number is suggested to be 4 and it is suggested to be a secondarily balanced polyploid.
6. Pollen grains show a maximum of 3·3% sterility.