Terminal Inflorescence Research Articles

Floral Development, Anatomy, and Embryology of Collinsia heterophylla with Some Notes on Ten Other Species of Collinsia and on Tonella tenella

The apex that produces the decussate leaf primordia also produces the "whorls" (separated close spirals) of floral primordia in the terminal inflorescence of Collinsia heterophylla, with the only morphological change during the transformation being an increase to about twice the size. A two-layered tunica surrounding a densely staining corpus occurs in vegetative, inflorescence, and floral apexes. Flowers of C. heterophylla are hypogynous, sympetalous, zygomorphic, and bicarpellate, and the four stamens and one staminode are epipetalous. This species, in common with other members of the Scrophulariaceae, has its floral organs produced in the sequence of sepals, stamens, petals, carpels, and ovules. Collinsia and Tonella, which have a distinct staminode, appear to occupy an intermediate position in a postulated series in evolutionary reduction of the androecium in the family. In the base of the receptacle 10 bundles (five median sepal alternating with five joint lateral sepal-petal bundles) diverge outward, leaving gaps. The staminode-dorsal carpel bundle is undiverged from the posterior median sepal bundle at origin but soon separates from it tangentially. The median sepal gaps soon close, and almost immediately the four stamen bundles diverge, leaving large gaps which gradually close. Above this level one dorsal carpel trace arises from the vascular cylinder, and the other separates tangentially (or obliquely) from the staminode bundle. Shortly after its divergence a dorsal carpel bundle gives rise to two small laterals. Slightly below the base of the ovary two pairs of lateral carpel bundles arise from the vascular cylinder before it splits to form the two ventral carpel complexes. The latter enter the axis of the ovary in the plane of the septum, and thus each is probably composed of two ventral traces from adjacent carpels. Two branches of each ventral carpel complex enter the placentae and supply the ovules. One other branch from each ventral carpel complex passes upward and outward through the septum. It divides, and the halves enter different carpels, where they merge with the dorsal carpel bundles near the top of the ovary-an unusual condition. Differentiation of provascular tissue proceeds acropetally in the midrib bundles of leaves, bracts, sepals, and petals and in the stamen, staminode, and all carpel bundles. The order of appearance of provascular tissue in the floral organs is the same as the order of the initiation of those organs. Xylem lignification is discontinuous in the main bundles of leaves, bracts, and all floral organs. The direction of lignification is mainly acropetal in the median leaf, sepal, and dorsal carpel bundles, largely basipetal in the stamen and staminode bundles, and about equally acropetal and basipetal in the bract, lateral sepal, and ventral carpel bundles. No lignified xylem is found at any time in the base of the stamen, staminode, and dorsal carpel bundles connecting these to the receptacular vascular tissue. The provascular and mature phloem connection is complete, however. Microsporogenesis is similar to that in most angiosperms, and the single pollen grains are shed in the two-celled stage. As in other members of the Scrophulariaceae, the nuclei of tapetal cells of Collinsia divide mitotically, and the two nuclei may then fuse or they may divide and the four resulting nuclei fuse. The maximum growth rate of pollen tubes in styles was calculated to be approximately 2 56 mm per hour in the conditions under which the plants were grown. In the essentially campylotropous, unitegmic, tenuinucellate ovules a single archesporial cell enlarges to form the megaspore mother cell. This undergoes meiosis, forming a linear tetrad of which the chalazal spore functions to produce an eight-nucleate megagametophyte. Development is thus of the Polygonum type. Polar nuclei fuse before double fertilization occurs. The megagametophyte of C. heterophylla differs only in certain details-for example, time of disintegration of antipodals-from that in other members of the Scrophulariaceae. Embryo development is probably of the Onagrad type. Endosperm development is cellular. The endosperm cell nearest the chalaza early develops into a massive binucleate haustorium, and several (usually four) endosperm cells in the micropylar end form uninucleate haustoria. The centrally located cells divide to form the endosperm proper. In the mature seed all that remains of the integument is the endothelium, the outer epidermis-which consists of large cells that have thin tangential and thick (non-lignified) pitted radial walls-and a few intervening cells where the seed was attached to the placenta. The endosperm at seed maturity consists of thick-walled (non-lignified) cells filled with large droplets of oil and tiny granules of protein. The close relationship among species of Collinsia (C. heterophylla, C. concolor, C. austromontana, C. tinctoria, C. stricta, C. arvensis, C. bruceae, C. solitaria, C. verna, C. corymbosa, C. multicolor) and of Tonella tenella to Collinsia is supported by studies of their vascular anatomy, organography, and gametophyte development. No characters of internal structure can be used to distinguish among them.

The growth of safflower (Cathamus tinctorius L.) in a low latitude environment

At the Kimberley Research Station, W.A., growth studies on safflower were made on a uniform crop in one year, and in the following year on a density experiment and a time of nitrogen application experiment. Density treatments extended from 25 to 1120 plants m-2, to exploit as fully as possible the light environment in the crop canopy. In the nitrogen treatments, 90 kg ha-1 of nitrogen was applied at seeding, elongation, and budding in an attempt to increase grain yield by increasing the size of the terminal inflorescences. Although at higher densities the light microenvironment was exploited early there was no increase in total dry matter, and grain yield was highest with densities of about 100 plants m-2. In the nitrogen experiments the early indications of higher yields due to treatment did not materialize as the crop matured, because rising temperatures at flowering and during seed development retarded further growth. On the average, grain yield or economic yield constituted 20% of the total dry matter of tops. There was a greater difference in total dry matter and grain yield between years than between treatments within one year, and this was interpreted as a time of planting effect. The effects of rising temperatures during seed formation are discussed. Avenues for further work are suggested.

Changes in the anatomical structure of the shoot apex ofSenecio vulgaris L. during ontogenis in relation to the formation of leaves and inflorescence

An investigation was made of the anatomical structure of the shoot apex ofSenecio vulgaris L. a photoperiodically neutral plant, and compared with the formation of successive leaf primordia along the axis up to the initiation of the terminal inflorescence. In the shoot apex of a germinating plant a central zone can first be distinguished from the peripheral zone which is composed of small and intensely stained cells. Later, a rib meristem appears. At the time of the initiation of the middle (the largest) leaves, the shoot apex has a distinct small central zone and a well developed peripheral zone and rib meristem. Between these zones there is a group of cells dividing in all directions, the subcentral zone. At the time of initiation of the last leaves, the central zone extends to the flanks and gradually ceases to be distinguishable. At the same time, the subcentral zone increases in size. This is caused first by cell division and later, with the initiation of the last, most reduced leaves, by enlargement of the cells. Vacuolization in the inner part of the apex and the arrangement of the superficial cells in rows parallel to the surface of the apex, is a preparatory step to the initiation of the inflorescence.

Flower initiation in pasture legumes. IV. Flower initiation in Trifolium pratense L.

An early strain (Cowgrass) and a late-maturing strain (Montgomery) of red clover (Trifolium pratense L.) were grown at Melbourne, lat. 38°S., to study flower initiation and the relationship between initiation and flowering, because of the importance of flowering to the use of the species as a source of hay. The terminal inflorescence in red clover arises from a lateral bulge at the shoot apex, and the main shoot of the plant is strongly vegetative, only becoming reproductive in a proportion of plants under long photoperiod, particularly continuous light. In both strains, whether first-year or older plants, flower initiation and therefore flowering were confined to a short period of the year, the early strain having the longer period. Sowing the two strains at intervals through the year in the field, under natural and long photoperiods, showed the importance of both photoperiod and temperature to initiation. Both strains were hastened by a long photoperiod whatever the temperature, and initiated at a similar low leaf number, but the early strain was able to initiate at a shorter photoperiod than the late one. Seed vernalization had almost no effect; but at photoperiods of 14 to 11 hr, high temperatures strongly retarded Cowgrass and appeared to prevent initiation in Montgomery. The capacity of Cowgrass to initiate at a shorter photoperiod and at higher temperatures than Montgomery explains its longer flowering season in temperate latitudes. These genetic differences suggest that an appropriate environment can be used to differentiate early and late-flowering strains for seed certification, and that late strains would stay vegetative at low latitudes and would therefore be less useful as a source of hay than early ones.

The Three Species of Stillingia (Euphorbiaceae) in Far Western Texas

Keys, descriptions, and notes on nomenclature, ecology, and dis- tribution are given for Stillingia Treculiana, S. sylvatica, and S. texana of the trans-Pecos and adjacent counties. No new names or taxa are published. For our three species of Stillingia complete and accurate descriptions and notes on ecology and detailed distribution in extreme western Texas are given for the first time in this, another of our papers on the members of this family in this poorly known region. An index map of the region was published previously (Johnston and Warnock, 1962). From among our other euphorbiads the members of this genus can be picked out on the basis of their herbaceous habit, and terminal spikelike inflorescences which are, more precisely, spiciform thyrses, and the glandlike stipules at the bases of the bracts as large as the bracts themselves. They are unusual also in their lack of pubescence, and in that each of the 3 styles is entire, and in the milky sap. A distinctive characteristic, and the one which distinguishes Stillingia from the very closely related tropical genus Sapium, as well as from our other genera, is the enlargement and induration of the lower portion of the ovary, its separation at maturity from the upper dehiscent por- tion, and its persistence as a triangular or three-pointed gynobase. The columella, a common postdehiscence feature among our euphorbiads, in Stillingia is fragile and does not long persist. KEY

Biological Activity and Localization of Phorate Residue Toxins in Soil-Drench Treated Chrysanthemums

Cholinesterase-inhibiting residues or phorate persisted in the foliage of standard disbudded chrysanthemums, Chrysanthemum morifolium Ramat., 141 days after treatment. In plants removed to phorate-free soil after a 24-hour exposure to a soil application of phorate, (200 m1. of a dilution containing 0.5 oz. phorate per 100 gallons water applied per 6-inch pot) cholinesterase inhibitory residues were detectable for more than 47 days. The residues in situ killed melon aphids, Aphis gossypii Glover, 45 days following the application. Hates in excess of 4 oz. per 100 gallons caused phytotoxicity after some 20 days. Two ounces were not sufficient to control two-spotted mites, Tetranychus telarius (L.). Cholinesterase-inhibiting residues of phorate were as much as 47 times greater in chrysanthemum foliage than in terminal inflorescences of the same plants. A positive correlation was not evident in It comparison of the magnitude of phorate residues (expressed in grams of tissue required for 50% inhibition of cholinesterase) with toxicity (expressed in time required for 50% kill of melon aphids) for the first 20 days after application. Only after this time did a positive correlation appear.

Axial Origin of the Terminal Inflorescence in the Genus Trifolium

J. L. STODDART1 states that floral initiation in red clover begins by the enlargement of the shoot apex. The following observations show that the actual shoot apex is absorbed by an adjoining lateral bud. The origin of the terminal inflorescence of this species as a lateral bud is therefore similar to that of the axillary inflorescence in other species.

Response of China aster to daylength and gibberellic acid

1. Plants of Callistephus chinensis cv. ‘Giant Comet’ were subjected to photoperiods of 8 or 16 hours. In short day (SD) a much greater number of leaves was formed than in long day (LD) before the terminal inflorescence was initiated. By transferring plants from LD to SD at weekly intervals it was established that in LD floral induction is completed about 6 weeks after sowing. 2. Inflorescence development proceeds faster in SD than in LD. Plants in continuous SD or LD flower almost simultaneously. Plants transferred from LD to SD six weeks after sowing, flower about a month earlier than those plants grown entirely in LD. 3. Gibberellic acid (GA3) did not affect inflorescence initiation in LD. In SD, however, GA3 applications reduced the number of leaves formed before the inflorescence. The maximal effect, obtained by spraying with a solution of 25 mg GA3/1 during 30 days, halved the difference in leaf number of untreated plants in LD and SD. The same effect was obtained when plants were sprayed 10, 20 or 30 times during this 30 day period. 4. Manipulation of the photoperiod allowed the development of a method to grow two generations within one year. This method, which is being used to speed up a breeding project, is briefly described.

Some Effects of Iron Deficiency on Flowering of Xanthium

1. Cocklebur plants (Xanthium pensylvanicum Wallr.) exhibiting iron-deficiency symptoms during photoinductive treatment either did not flower subsequently or flowered abnormally when maintained on complete nutrient solution. 2. The abnormal flowering was characterized by (a) the delayed appearance and slower development of terminal staminate inflorescence primordia, (b) the development of pistillate inflorescences, which were surrounded by rosettes of many leaves, and (c) the failure of pistillate inflorescences to produce mature burs. 3. Plants which had recovered from iron deficiency and were then subjected to photoinductive treatment flowered normally. 4. A low carbohydrate level in - Fe plants during induction is apparently not responsible for their abnormal flowering, since - Fe plants supplied with 10% sucrose solution during photoinductive treatment also flowered abnormally. The - Fe plants supplied with sucrose soon exhibited more vigorous stem elongation than did - Fe plants not given sucrose, ...

Introgression in Adenostoma

On any theory of evolution, differences between individuals are compounded somehow into specific and eventually into generic differences. An efficient analysis of plant-to-plant variation should give us critical data for determining the origin of the basic variability which is the raw material for evolution. If, as is currently generally believed, this basic variability results from gene mutation, then an efficient analysis of individual-to-individual differences should reveal the kind of local differentation pattern which might be explained on such an hypothesis. For such studies Adenostoma fasciculatum, the common chamise of coastal California, is excellent material. Over a large part of its range, plant-to-plant variation is so conspicuous as to compel attention. In the hills behind Palo Alto or on the burned-over slopes of Mt. Diablo, virtually any three or four plants of Adenostoma chosen at random can be used to demonstrate the magnitude of this variation and its strongly germinal basis (figs. 1 and 2). If we examine adjacent bushes of Adenostorna along a mountain pathway, it is easy to show that though they are growing so closely side by side that their branches interlock, we can readily distinguish the branches of any one bush by the general similarity of their inflorescences. Though parts of some bushes may be in the sun and parts in the shade, though some branches may be strong terminal leaders and others physiologically suppressed, all the branches on any bush have a nucleus of common features, while the differences from one plant to another are always perceptible and are frequently conspicuous. If we choose a few good-sized bushes and remove the terminal inflorescences from each four to five well-developed branches from each and lay them in the pathway, an independent observer can easily determine from exactly which bush in the vicinity each set of branches was collected. By actual experiment it has been determined that under these conditions a class of students can match up a series of branches with a series of bushes without a single error. Any three such Adenostomna bushes are as different from each other as are three named varieties of lilacs in a collection in a botanical garden. Like the lilacs, they have a strong tendency for all the trusses of bloom on any one bush to be recognizably similar and yet for the trusses to vary perceptibly (and sometimes conspicuously) from one plant to another. Unlike the lilacs, however, the variation is largely confined to differences in the size and branching pattern of the inflorescence. Frequently this may be the only noticeable difference between adjacent bushes, though occasionally one may also find single plants which differ in height, in length of the leaves, in leaf shape, and (even more rarely) in the scurfiness or pubescence at the base of the calyx. Flower color, flower size, and flower shape are not noticeably different in any of the material.

THE VEGETATIVE DEVELOPMENT OF THE POTATO PLANT

A study of the vegetative growth of potato plants indicated that all varieties grown under identical conditions are likely to show similar growth rates during the early stages of development.Differences in total leaf area per plant between varieties became apparent at the stage when rapid development of axillary shoots from the main axis occurred. The maincrop varieties, Stormont Dawn and King Edward, attained a greater total leaf area than the early varieties, Ulster Chieftain and Arran Pilot, because of the greater development of axillary shoots.It is suggested that the number of nodes produced beneath the terminal inflorescence on the main axis approximates to a constant value, independent of variety. Varietal differences were manifested in the distribution between leaves above ground and stolons below, the early varieties producing fewer leaves above ground than the maincrop, in inverse proportion to the number of underground stolons.The yields of tubers per plant are given for four varieties. Differences between varieties in the rate of tuber formation are related to differences in the development of haulms.It is considered probable that the potato plant exhibits a basic growth form which is modified in each variety in a characteristic manner according to the stage in the growth cycle and the rate at which the growth substances are distributed to the various organs of the plant.

REFLECTION OF VISIBLE AND INFRARED RADIATION FROM LEAVES OF DIFFERENT ECOLOGICAL GROUPS

American Journal of BotanyVolume 38, Issue 5 p. 327-331 Article REFLECTION OF VISIBLE AND INFRARED RADIATION FROM LEAVES OF DIFFERENT ECOLOGICAL GROUPS W. D. Billings, W. D. Billings University of Nevada, Reno, NevadaSearch for more papers by this authorRobert J. Morris, Robert J. Morris University of Nevada, Reno, NevadaSearch for more papers by this author W. D. Billings, W. D. Billings University of Nevada, Reno, NevadaSearch for more papers by this authorRobert J. Morris, Robert J. Morris University of Nevada, Reno, NevadaSearch for more papers by this author First published: 01 May 1951 https://doi.org/10.1002/j.1537-2197.1951.tb14831.xCitations: 53AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume38, Issue5May 1951Pages 327-331 RelatedInformation

Delayed Germination of California Oatgrass, Danthonia californica1

Delayed germination of Danthonia californica was studied in 16 seed collections obtained from native stands in California in 1947. Seedling emergence 16 weeks after planting ranged from only 2.5% to 16.0% when untreated terminal inflorescence seed was planted in unsterilized greenhouse soil. Concentrated sulfuric acid treatment of seed hastened emergence and increased the number of seedlings. Response to treatment was compared in the seed germinator, greenhouse, and field. Field plantings benefitted most from acid treatments of considerably shorter duration than those yielding the best results in the germinator. In field tests the 15-minute sulfuric acid treatment yielded the greatest seedling emergence from terminal inflorescence seed. Axillary cleistogenes were found to require less treatment and exhibited the best field response to a 5- to 10-minute acid treatment. Weakening of the seed coats appears essential overcoming the delayed germination of Danthonia californica. In these experiments this was accomplished by sulfuric acid treatment or by cutting the seed coats. Hulling without seed coat injury was of little benefit. The seed coats appear to delay germination through mechanical restraint or restriction of gas exchange or both. They do not prevent water absorption.

RESPONSE OF KALANCHOE TUBIFLORA TO X-RADIATION

A study extending over three and one-half years was made of the vegetative and reproductive growth of Kalanchoe tubiflora, (Harvey) Hamet., a Madagascan succulent of the Crassulaceae. This plant, which grows well in greenhouses of this country particularly during the hot days of late spring and summer, is well adapted to a study of responses to various environmental factors. Studies (2) have been made of its response to different light intensities, different qualities of light as supplied by fluorescent light tubes, supplemental artificial light, and to X-radiation. The present paper will be limited to the response to X-radiation. Plants of this species of Kalanchoe were first seen by the writer in the gardens of the Atkins Institution of the Arnold Arboretum at (Soledad) Cienfuegos, Cuba. The present superintendent, Mr. Frank Walsingham, suggested their probable value for experimental work and made it possible to secure some young plants from Mr. A. C. Jordahn, then associate superintendent of the Fairchild Tropical Garden at Cocoanut Grove, Florida. From these original plants, hundreds have been grown in the University of Colorado greenhouse. Kalanchoe tubiflora has a long slender unbranched stem with spirally arranged leaves. However, vegetative shoots which arise in the region of the terminal inflorescence after the flowers have faded, give old plants a branched appearance. The almost cylindrical leaves which are 4-5 mm. wide and 6-7.5 mm. long are normally strikingly mottled with purple streaks or blotches. Typically the leaf tip has from four to seven small teeth. When the plant is reproducing vegetatively, protuberances extend outward from between the teeth. Clamp (1) refers to the protuberances as leaf claws. At the tip of each claw, develop little plantlets each consisting of a short disc-like stem bearing two pairs of leaves (Fig. 1). While in this two-leaved condition, the plantlets fall to the ground and develop into new individual plants.

STUDIES ON AMBROSIA. IV. EFFECTS OF SHORT PHOTOPERIOD AND TEMPERATURE ON SEX EXPRESSION

STUDIES ON AMBROSIA. IV. EFFECTS OF SHORT PHOTOPERIOD AND TEMPERATURE ON SEX EXPRESSION

Effect of Nutrition and Age upon Rate of Development of Terminal Staminate Inflorescences of Xanthium pennsylvanicum

1. Xanthium pennsylvanicum plants low in phosphorus, potassium, and nitrogen had the same critical day length as plants supplied with a nutrient solution containing all these elements. 2. Rate of development of terminal inflorescences of -N, -K, and -P plants was considerably affected at photoperiods near the critical. Lack of phosphorus decreased the rate of development more than lack of either nitrogen or potassium; and lack of nitrogen resulted in slower development than lack of potassium. 3. With each half-hour increase in length of the dark period from 81/2 to 101/2 hours there was an increasing tendency for the plants low in phosphorus, nitrogen, or potassium to develop at the same rate as the plants grown with a non-deficient solution. Thus it appears that by increasing the length of the dark period the detrimental effect of mineral deficiency on rate of development of floral primordia may be overcome. 4. Age of leaf tissue definitely affects the critical day length. The first fully expanded leaf h...

FLORAL DEVELOPMENT OF CERTAIN SPECIES AS INFLUENCED BY X-RADIATION OF BUDS

X-radiation of susceptible plants which are nearing the reproductive stage usually causes abscission of buds or certain types of anomalies in flower structure. An earlier paper by the writer (3) reports the occurrence of abnormalities of floral parts including the production of double flowers when tomato plants were given three X-ray doses previous to blossoming. A single heavy dose usually causes bud abscission ; later growth may produce blossoms some of which are normal, while others are double or triple. Goodspeed (1) noted that in Nicotiana langsdorffi buds of the terminal inflorescence were abscissed immediately after treatment and all the first flowers on laterals were abnormal. After a short time, only normal flowers were produced. Moore and Haskins (4) reported that irradiated petunia buds gave rise to blossoms displaying various anomalies. The present article discusses various types of abnormalities in flower structure which result when young buds are irradiated with one medium dose. A rather extended analysis of the relationship found to exist between the degree of bud development at the time of treatment and the occurrence and character of the anomalies produced will be given for one of the species used in the experimentation.

PHOTOPERIODIC RESPONSE OF CERTAIN LONG AND SHORT DAY PLANTS TO FILTERED RADIATION APPLIED AS A SUPPLEMENT TO DAYLIGHT

In a previous publication (4) it was shown that the red portion of the visible spectrum was especially effective in inducing photoperiodic responses in long day plants when used to prolong short winter days. These responses generally included earlier flowering, increased internodal development, and a greater top-root ratio. The yellow, blue, and green regions of the visible spectrum of wavelengths shorter than 650 mp were relatively much less effective. It was further indicated that the infra-red was relatively ineffective under the conditions of experimentation. When the white radiation of an incandescent lamp was used to prolong the normal winter daylight period, the responses obtained were like those produced by red radiation (650to720mM) alone. Since all of the plants studied in the above mentioned paper were of the long day type, it was considered of interest to determine the spectral region responsible for the vegetative condition induced in typical short day plants as contrasted with the reproductive responses of long day plants, such as occurs when the white radiation of an incandescent lamp is used to prolong the day. Schaffner (3) has shown that corn, which normally produces staminate terminal inflorescence under long summer days, tends to give rise to carpellate flowers in the tassels under the short days of winter, especially when the corn is seeded around the first of November in the vicinity of the latitude of 40° N. Corn might, therefore, be considered a short day plant so far as femaleness in the terminal inflorescence is concerned.

Control of Sex Reversal in the Tassel of Indian Corn

1. Narrow-grain Evergreen sweet corn is decidedly influenced in its sexual expression by the length of the daily illumination period, and the amount and degree of reversal to femaleness in the tassel is subject to experimental control. Limited experiments with Country Gentleman sweet corn indicate that the same condition is present in that variety. 2. Corn planted on November 1 in the greenhouse will, with proper substratum and heat, show 100 per cent of the individuals with some degree of female expression in the tassel, while that planted in the spring or summer will normally show only pure staminate tassels. 3. Corn planted either before or after this date, under similar conditions, will show a ratio of sex reversal inversely proportional to the length of the daylight. With the approach of equal day and night periods of 12 hours each, little or no reversal will occur in the tassel. 4. The time and point of female sex determination can be thrown back to the second or third leaf nodes from the base of the plant. 5. Whenever the female state is established in the main stem, either above or below the point of lateral ear development, the internodes become decidedly flexuous, and in extreme cases they are even thrown into loops. 6. Any plot of corn, grown in the greenhouse, can be so planted and developed that the individuals of the population will show every gradation, from the normal monoecious type, with pure carpellateness expressed in the side branches and pure staminateness in the terminal inflorescence, to an absolutely pure female condition, all the flowers of the terminal inflorescence as well as those of the lateral ears being purely carpellate.