CONTRIBUTIONS TO THE MORPHOLOGY OF THE NYCTAGINACEAE II. Floral Anatomy of Some Species* BY H. P. SHARMA (National Botanic Gardens, Lt~cknow) Received September 15, 1962 (Communicated by Dr. V. Puri, r.A.sc.) INTRODUCTION THE order Centrospermales has been engaging the attention of the author for sometime past. Investigations in different aspects of the family Nyctagi- naceae were taken up as a part of these studies. Besides, all genera of this family possess a single basal ovule which, like all cases of basal placenta- tion, is of special interest. An earlier communication (Sharma, 1962 a) deals with anatomy of the node and inflorescence of some species. Earlier to this, Joshi and Rao (1934) studied the floral anatomy of four species of this family. Bhargava (1952) recorded some differences with their observations in the case of Boerhavia repanda. MATER/ALS AND METHODS The present communication deals with six species of the Nyctaginaceae. These are: Boerhavia diffusa Lima., B. repanda Willd., Bougainvillea glabra Chois, Mirabilis jalapa Linn., Pisonia linearibracteata Heimerl and P. acu- leata Linn. Material of Pisonia linearibracteata was obtained from the Herbarium of the Botany Department, Meerut College, Meerut and that of P. aculeata was received from the Government Gardens, Bangalore. The rest were collected locally. Serial microtome sections 6-10/~ thick were cut and stained in both crystal violet-erythrosin and safranin-fast green combina- tions. Flowers clea~ed in lacto-phenol were also dissected under a stereo- scopie binocular and proved extremely helpful. OBSERVATIONS Boerhavia diffusa.--There are two to three unequal medullary bundles in the centre of the pedicel as also reported by Joshi and Rao (1934) (Text-Fig. 2). * Major part of this work was carried out at the School ofPtant M'orphol~gy, Mecrut College, Meerut. m 149 150 H.P. SHARMA These reorganise and form a hollow vascular cylinder with xylem distributed in 5--6 patches. From this five (six in abnormal cases) large tepal cords diverge outward on alternate radii leaving as many vascular patches in between (Text-Figs. 3, 10 and 11). A little higher up the latter expand sideways connecting the outward diverging perianth traces by patches of procambial tissue (Text-Figs. 4 and 10). No mention of these alternating vascular patches has been made by Joshi and Rao (1934). In two instances, these vascular patches gave out well-marked vascular cords for the perianth (Text-Figs. 12 and 13, x). Thus in this case the perianth receives its supply in the form of 10 cords. The procambial tissue presists right up to the top of the lower globose part of the perianth where the five perianth traces show conspicuous swelling and cross-connections (Text-Figs. 14 and 16). In the petalold limb five weaker perianth cords continue up (Text-Figs. 15 and 17). These cords show frequent cross-connections (Text-Fig. 17). A little below the tip they give out two to three diverging veins which end blindly. The main bundle ends in a number of branches within the dorsal spine (Text- Fig. 17). After the departure of perianth traces whatever vascular tissue is left in the pedicel again reorganises into a hollow cylinder from which 2-4 stamen traces diverge out, one for each stamen (Text-Figs. 1, 6, 7 and 13). They continue undivided throughout the filament (Text-Figs. 8, 9 and 13-15). The remaining part of the stele again forms a hollow cylinder in the centre (Text-Fig. 13). This gives off a prominent carpel dorsal trace on one side (Text-Figs. 8 and 18). Nearly half way up the gynophore it (carpel dorsal) expands perceptibly and again contracts further up (Text-Fig. 18). Beyond this region it runs up to the stigma without showing any further change. In the stigma, however, it expands considerably and ends in a broad tracheidal plate (Text-Fig. 19). After the departure of the carpel dorsal the remaining vascular tissue is found to be bilobed. At the level of the carpel dorsal expansion it gives out a small strand on one side which ends blindly (Text-Fig. 18, R). The remaining branch continues up for the ovule. Before entering the ovular stalk it again expands perceptibly (Text-Fig. 18). As it enters the ovule it takes an abrupt turn sideways (Text-Figs. 1 and 18). Boerhavia repanda.--There are two sets of bundles at the base of the pedicel. Of these, two to three are medullary bundles and are surrounded by an outer ring of feebly developed bundles. The former form a hollow cylinder below the receptacle (Text-Fig. 20). This cylinder furnishes the various floral traces while the bundles of the outer ring fade completely with- out taking any part in the floral supply. As/he pedicel expands five perianth Tnx'r-Ftcs. 1-19. Boerhavia diffusa. Fig. 1. Semi-diagrammatic L.$. of a £<vcr Figs. 2-9. Serial transections era flower•(with six perianth lobes) from base upward. Fig. 2. Pedicel region showing an outer vascular ring and three bundlesin the centre. Fig. 3. Perizr.th dorsals (P) arising. Fig. 4. Proqambial patches (L) arising from vascular tissue on alternate. radii. Fig. 5. Showing definite vascular patches (X) alternating with perianth dotsals, Figs. 6 and 7. Procambialring connecting the perianth dorsals; three stamen traces (S) arising~ Fig. 8. Carpel dorsal (D) and ovular trace (O) arising. Fig. 9. Perianth tube narrowing; ovary cut a little below the base of the style. Figs. 10-15. Serial trafisections of another flo~cr with five perianth lobes and two stamens. Mark the vascular patches(X) alternating witht[.e perianth dorsals in Figs. 12 and 13. Fig. 16. A cleared flower showing vasculatme in the lower portion of the perianth tube. Fig. 17. The petaloid portion of a cleated perianth tube cut and spread out to show the vascular supply in this region. Yig. 18. A cleated and dissected ovary showing vascular supply to the ovule (O). Note the supply 'R' ending blindly and the ovular bundle expanding nearly half way up. Fig. 19. A cleared style showing the carpellary dorsal ending in a tracheidal plate within the stigma. (D, carpellary dorsal ; L, procambial patches arising on radii alternating with perianth dor- sals; O, ovular trace; P, tepal dorsals; R, 'residual' stelar tissue; S, stamen traces; X, vascular patches in between tepal dorsals.) 152 H.P. SHARMA traces diverge outward from the medullary cylinder (Text-Figs. 21 and 22). These are soon followed by five more traces alternating with those of the first set (Text-Figs. 21 and 22). As the latter traces move outward some procambial tissue from either side of the resulting gaps also diverges out along with these, so that from the very beginning the latter set of traces have two procambial patches on their either side (Text-Fig. 22). No mention of these has been made by the earlier authors. This procambial tissue expands and forms a ring on the inner side of the perianth traces. Soon this ring gives out procambial patches one on either side of the two sets of perianth traces. The innner ring fades a little higher up. The perianth bundles continue up in this state (Text-Figs. 22-25). Near the top of the giobose part the lateral procambial strands of each set expand sideways connecting the adjacent perianth bundles (Text-Fig. 26). These transverse connections, however, soon fade leaving only the median bundles in each of the ten ribs to continue up (Text-Fig. 27). As the globose pal't of the perianth opens into the petaloid tube, the latter arising strands become weaker and the lobes flatten against these. Higher up as the petaloid tube opens into the broad limb these strands split up into two each (Text-Fig. 27). The daughter branches diverge a little from each other and anastomose with branches from the adjoining midribs (Text-Fig. 27). A httle above this region the midrib bundles also split into two each (Text-Fig. 27). The two daughter bundles continue up and give out a few diverging branches for portions between the midribs. One of these branches ultimately enters the short dorsal spine where its xylem breaks up into a large number of branches (Text-Fig. 28). These, however, soon fade away (Text-Fig. 28). After the departure of perianth traces five vascular patches are left on the inner side of the tepal marginal traces. These soon reorganise and form a hollow cylinder from which two to four traces are given out for an equal number of stamens (Text-Fig. 24). There is no branching in the stamen bundles throughout their course in the filament. In one case, however, the filament enlarged considerably just below the anther lobes and the vascular bundle also showed some branching in this region (Text-Fig. 29). After the divergence of the stamen traces the remaining vascular tissue in the centre rcorganises into a hollow cylinder which breaks up into a carpel dorsal on one side and a small arc opposite to this below the locule (Text- Figs. 25 and 30). A little above its point of origin the dorsal bundle expands slightly and continues unbranched up to the stigma (Text-Fig. 30). Unlike the previous species it does not end in a tracheidal plate. Contributions to the Morphology of the Nyetaglnaceae--H 153 TExT-FIGs. 20-32. Boerhavia repanda and Mirabilis jalapa. Figs. 20-31. Boerhavia repanda. Figs. 20-27. Serial transections of the flower ofB. repanda from base upward. Fig. 20. Show- ing hollow receptacular stele. Figs, 21-23. Five tepal dorsals (P) and five marginais (L) arising. Note proeambial patches arising between tepal dorsals.