SEED-TESTING NOTES.

New Zealand Journal of Agriculture, Volume XVII, Issue 6, 20 December 1918, Page 347

SEED-TESTING NOTES.

THE BIRDSFOOT TREFOILS.

By

E. BRUCE LEVY,

Biological Laboratory.

There are four species of birdsfoot trefoils of agricultural significance in New Zealand, and it has become custom, as in the case of the poas, to designate these by their botanical namethus, Lotus major (greater birdsfoot trefoil), Lotus hispidus (hairy birdsfoot trefoil, or Boyd’s clover), Lotus angustissimus (slender birdsfoot trefoil), and Lotus corniculatus (birdsfoot trefoil). .

Lotus major and Lotus hispidus are fairly largely used, the amount of seed sown annually in New Zealand being approximately io tons to 15 tons of Lotus major and approximately 10 tons of Lotus hispidus. Not more than 2 cwt. of Lotus corniculatus is used. At one time the only lotus sown in New Zealand was Lotus corniculatus, but during the past ten years the amount sown has steadily decreased. Dr. Hilgendorf, in his “Pasture-plants and Pastures of New Zealand,” strongly recommends the sowing of Lotus corniculatus. on the light soils of Canterbury. It is probable that it would fill a very useful place on certain types of pasture-land, and experimental work on its real pastoral value should be carried out. Certainly a permanent clover that will grow vigorously in pastures on light dry land where the. growth of white clover is small and intermittent is an urgent requirement on much of the rotation grass-land of the. South Island. .; . ;

The seed of the true Lotus angustissimus is not on the market, although a little occurs as an impurity of Lotus hispidus. It is necessary here to point out that, as.far as the New Zealand trade is concerned, the seed of Lotus hispidus and Lotus angustissimus is one and the same, and although sacks may be branded “ hispidus ” and “ angustissimus ” respectively, yet both lots will be one variety—namely, Lotus

hispidus ; or if two orders came in, one for hispidus and one for angustissimus, both would be supplied from the same seed, although not necessarily from the same sacks.

The early history of Lotus-hispidus-seed production in New Zealand is of some interest. The first seed was harvested in 1904 at Waikumete,

near Auckland, by an old resident, Mr. W. Levy, who had been growing

the plant for some five years previously, he having collected and sown a little seed from an orchard at Henderson, in which district the plant

made its appearance some twenty-five years ago. The amount harvested was io lb., which was sold to a firm of Auckland seed-merchants, Messrs. Hesketh and Aitken, at is. per pound. The following year about 2 cwt. was harvested, and by 1911 the sale had increased to 3 tons. The price in 1910 was Is, 6d. per pound, and in 1911 is. 3d. per pound. Up to this time the seed had been bought and sold as Lotus major. In 1912, however, the plant was identified by a local botanist as Lotus angustissimus, and thenceforward the seed was sold to the trade under this name. As has been pointed out, however, more recent investiga-

tions have shown that the plant was not Lotus angustissimus but Lotus hispidus, although Lotus angustissimus does occur generally throughout Lotus hispidus crops. • ' ■. ft. .

After 1912 the business passed to Messrs. W. P. Levy and A. A. Levy, who (up to the time the first-named brother enlisted for active service) were the principal producers of this seed. All the Lotus hispidus seed sold in New Zealand is produced locally, mainly throughout the Auckland Provincial District.

Lotus major is' saved for seed mainly in the Auckland Province, but prior to the war the greater portion was imported, mainly from Germany. This seed was exported from the latter country under the name of Lotus villosus or Lotus uliginosus, which names are the European trade names for the Lotus major of the New Zealand seed trade. Lotus major is very variable with regard to certain characters, such as hairiness, and in consequence several botanical names have been given to the plant. Lotus major Sm., Lotus uliginosus Schk., and Lotus villosus Cross & Germ, all refer to the one species. There are apparently a good many different strains, but whether or not these

breed true from seed and are good agricultural species, or whether they are due either to the habitat in which they are growing or to crossfertilization, has not yet been ascertained.

What little Lotus corniculatus seed is sown is imported. The Auck-land-grown Lotus major seed at present on the market is very unsatisfactory from a purity point of view, as the seed crops are almost invariably a mixture of Lotus major and Lotus hispidus, and as these two seeds are impossible of separation mixed lines are frequently met with. There is really no particular harm in sowing these two seeds mixed, for both plants do well, in the same situations, although Lotus major ' prefers a .wet or swampy habitat, and on such areas Lotus hispidus may be less desirable than Lotus major. Again, at the present time Lotus major is worth 4s. 6d. per pound, while Lotus hispidus is only is. 6d. per pound. In general, however, provided the price asked is commensurate with the purity analysis, there is really little objection to. sowing these two seeds in a mixed condition.

It is to be deplored, however, that more systematic methods have not been adopted in the saving of such and similar seeds in New Zealand, for there is little doubt that seed-growing here could be raised to quite an important industry. This can only be attained when the seed crop is looked upon as a primary product, and not as a secondary product as at present, and when efficient methods are adopted in place of the loose unsystematic ones at present in vogue.

The high average extraneous-seed content , of Lotus major is due almost entirely to the presence of Lotus hispidus. One sample analysed contained 95 per cent., while others varied between 40 per cent, and 80 per cent. It will be noted from the analyses that the New Zealand seed-merchant is skilful enough not to sell the more expensive seed Lotus major in place of the less expensive Lotus hispidus, whereas Lotus major with a considerable amount of Lotus hispidus in it seems to find acceptance and to be passed on without many questions being asked. Generally speaking, when Lotus hispidus is not present the purity of Lotus major is fairly satisfactory. The sample, however, should be carefully examined for dodder. The impurity most frequently met with in Lotus corniculatus is rib-grass (Plant ago lanceolata).

The identification of the seeds of these four lotus species can be well established with the aid of a pocket-lens magnifying ten to fifteen diameters. The key which follows, in conjunction with the botanical description of., each seed, 'together with the photo-illustrations, should afford a readv means of identification. . -

Key to Identification of Individual Seeds of the .Four Lotus Species. 1. .. Surface of seed speckled . . : . . .. . . .lorfjhi. • . 2 ia. Surface of seed not speckled . . ... . . . ‘ . . . . ... : 3 2. Seed large ; rich dark brown in colour ; speckles a still darker brown . . L. cdrniculatus. 2A.. Seed small ; greenish-yellow to dark purple ; speckles dark purple .. L. hispidus. 3. Seed uniform olive-green in colour .. .. .'. ... L. major. 3a. Seed not olive-green in colour . . ... . . .. . .. 4 4. Seeds brown in colour • ... . . ... ... . . ■ . . 5 4A. Seeds not brown in colour . . . . . . .... . . 6 5. Seed large ; rich dark brown ; -hilum edge same colour as faces . . . . - L. corniculatus. sa. Seed small; hilum edge darker brown than faces .. L. .major (see note). 6. Seeds uniformly purple-yellow to reddish-purple ; surface of a very clean , ■ appearance . . . . . . . . ... L. angustissimus. 6a. Seeds yellow or greenish-yellow . . . . . . • . . . • • . 7 7. Seed bearing a small fairly distinct protuberance on hilum edge. L. angustissimus. 7A. Seed bearing no such protuberance .. ... .... ■... L. hispidus.

Note.—Brown unspeckled seeds of Lotus hispidus also occur in samples that have been cut rather on the green side, but any brown seeds occurring in Lotus major samples are more likely to be Lotus major than Lotus hispidus, for the reason that Lotus hispidus ripens earlier than does Lotus major. Therefore any Lotus hispidus seeds in the Lotus major samples should be well matured—that is, unless wilful adulteration has been practised.

BOTANICAL DESCRIPTION OF LOTUS SEEDS.

Lotus major.

Size Average length, roimm.; average width, i mm. Shape : Somewhat conventionally heart-shaped, almost round ; faces convex, although less so than edges ; hilum edge flattened ; hilum conspicuous as a little pit bordered by white margin. Surface unspeckled; .smooth, semi-mat with dull gloss, presenting almost a greasy appearance. Colour varies ' from olive-green to greenish-brown to brown, but individual seeds ■ uniformly one colour.

Lotus hispidus

Size : Average length, i-i mm. ; average width, 0-94 mm. Shape : Almost rounded ; faces slightly less convex than edges ; hilum edge very slightly flattened ; hilum fairly well marked, but not quite so definite as in Lotus major. Surface usually speckled ; smooth, semi-mat with fairly bright gloss. Colour greenish-yellow, purplish-green, to dark purple; speckles dark purple. The .amount of speckling appears to be a variety character, as the writer has produced .an even yellow unmottled seed, and another with but very few and fine specks. Individual plants throw either speckled seed, slightly speckled seed, or purplishcoloured seeds.

Lotus corniculatus.

Size : Average length, 1-4 mm. ; average width, 1-16 mm. Shape : Fairly irregularly heart-shaped ; somewhat rounded ; at times elongated ; faces convex, although less so than edges ; hilum edge flattened, at times indented ; hilum fairly conspicuous, but no very definite white circular margin. Surface smooth ; mat with dull gloss. Colour a fairly uniform rich dark brown, with still darker brown speckles ; speckling slight, and in many seeds .absent or not readily discernible.

Lotus angustissimus.

Size : Average length, 0-9 mm. ; average width, o-8i mm. Shape : Almost rounded ; faces slightly less convex than edges ; hilum edge very slightly flattened ; hilum fairly well marked, as in Lotus hispidus ; a small, fairly distinct protuberance present on hilum edge. Surface smooth ; mat, with very slight gloss, presenting a very clean appearance. Colour uniformly yellow, purplish-yellow to purple, with no speckles.

Seed. 'Jr ■—'•Average Germination Percentage. Percentage of Hard Seed. Percentage of Extraneous Seeds. Minimum. Average. Maximum. Lotus major 41-0 71’7 96-0 24-0 35-o Lotus hispidus 3I-° 60-4 83-0 21-0 1-6 Lotus corniculatus . ; 12-0 51-0 71-0 31-0 4-0

The following table shows the relative average germination-capacity and purity of the lotus-seeds as sold in New Zealand:-