Vol. XV. No. 366. 



THE AGRICULTUKAL NEWS. 



155 



THE POISONING OF CRABS. 



The following note has been forwarded by the Agricul- 

 tural Superintendent, St. Lucia, as being of general interest. 

 The note his been prepared by ilr. It. W. Niles, Overseer 

 and Agricultural OfHcer, as a result of his experience in poison- 

 ing crabs at the Botanic Station, St. Lucia: — 



Crabs are often serious pests in gardens near the sea 

 and also in swampy land, and one of the ways for destroying 

 them is by boiling corn meal, and stirring in about a stick of 

 phosphorus to 8 gallons of meal Axhilst it is very hut, in 

 order to dissolve the phos[ihorus. 



This mixture is then put out about a dessert spoonful 

 in each hole, and the hole plugged witli earth or any other 

 .suitable material near at hand. 



Owing to the present war, corn meal has become a very 

 expensive item, and the writer finds that breadfruit (which 

 is very common in St. Lucia and many other West Indian 

 islands) or green banana.s, is quite a suitable sub.stitute for corn 

 meal. The breadfruit or bananas should be cut into pieces 

 and boiled until soft; these should then be mashed to form 

 a pulpy mass, and the phosphorus stirred in at the same rate 

 and in the same manner as in the case of the corn meal. 



GREEN DRESSING TRIALS IN DOMINICA. 



It is stated in the lleport on tlie Agricultural Depart- 

 ment, Dominica, for 1914-15, that seeds of the following five 

 species of green dressings were received from Dr. Cramer, 

 Chief of the Selection Station, Buitenzorg, for trial at the 

 Botanic Gardens: — 



Tephrosia Vogelii 



,, Hookeriana, var. amoena 



,, Candida 



Indigofera suffruticosa 

 Clitoria cajanifolia 



TephroMa candula has been under trial in Dominica 

 for several years, and a full account of its habit of growth, 

 etc., appeared in the Annual Prog re.ss Report for 1911-12. 

 It has been found an extremely useful plant for the purpose. 

 A supply of seed may be obtained by planters on application 

 at the proper season. 



Tephrosia Hooker iiina, var. amoena is identical with the 

 plant which has been grown in Dominica for several years as 

 Te2)hrosia pwpurea. The former name is the correct one. 

 (See Jvein Bulletin, No 1, 1914, and Aijricultnral News, 

 Vol. XIII, p 101.) A detailed account of this species 

 appeared in the Report for 1911-12. Not growing so tall 

 as Tephrosia Candida, it nevertheless forms a good shade and 

 is well worth the attention of planters. 



Tephrosia, Voe/elii is in habit and rate of growth very 

 similar to Tephroda Candida. Sown in August, it stood 

 the following April some 5 feet high and .showed no signs 

 of flowering. 



Indifjofera siiffrulicosa is a plant having a similar habit 

 to the common West Indian indigo {Indigofera Anil) 

 About three months from sowing the foliage of this species 

 was severely attacked by a green fly which caused many of 

 the leaves to drop. This, however, did not seem to check 

 the plants seriously. 



Indigofera svffrutieosa, as a cover crop, as far as present 

 experience goes, is in no way superior to Indigofera Anil, 

 a plant which has been somwhat neglected as a cover crop. 

 The ready way in which the latter establishes itself in Domi- 

 nica, and the rough treatment which it can stand in the way 

 of being cut down without losing its vigour should make 

 it popular with planters, and every ettbrt should be made to 



encourage its growth, e.specially between young cultivation; 

 it does not, however, thrive under the shade of lime and 

 other trees. 



Clitoria cajanifolia, Barth., is a species highly spoken 

 of as a green dressing in -lava, where it is regarded as one 

 of the best cover crops grown. There it lasts for two or 

 three years and forms a dense cover, protecting the soil from 

 wash, especially on hillsides. The few seeds that were 

 received in Dominica have germinated well, and the plants 

 are now 12 to ! cS inches high, and there is no indication of 

 flowering at the time of writing. It will be i.r.essary to 

 replant a larger area at the Station when seeds .' >■ ivailable, 

 before sufficient seeds can be raised for trial by p.aniers. 



There are several species of Clitoria common in the 

 West Indies, and all assist in conserving nitrogen in the 

 soil; but no attempt has been previously made in Dominica 

 to form a plot of these, and to use them as a cover crop. 



PLANT INHERITANCE OF MALE 



CHARACTERS ONLY. 



The following extracts dealing with the interesting 

 phenomenon of patrogenesis are taken from an article 

 on the subject in the Jourmd of Heredity for March 

 1916:— 



A cross between Tripmrum dactijloides, female, and 

 Eucldaena mexicana, male, has been carried through three 

 generations without exhibiting any indication of the 

 characters of the female parent 



The parental stocks were Ti i/is^'cui/i, dactyloides and 

 Eucldaena mex'cana. Tripsacum is a perennial grass native 

 in many parts of eastern United States, and is of no economic 

 importance. Euchlaena is an annual urass native in Mexico 

 and frequently grown in the United States for forage under 

 th€ name of 'teosinte'. These species not only belong to 

 different genera, hut are placed in separate groups of the 

 tribe Maydeae. The two genera, together with maize or 

 Indian corn, are the only American representatives of the 

 tribe. The plants dift'er profoundly in general appearance 

 as well as in structural details. 



In attempting to explain this complete absence of the 

 characters of the female parent two alternatives may be 

 considered: (1) The characters of the female parent have 

 been completely masked by those of the male, or (2) the male 

 nucleus devolops in the ovary to the complete exclusion of the 

 female, repre.senting in a way^the counterpart of partheno- 

 genesis. In the three generations of the progeny of this 

 hybrid at least 350 plants have been examined. This and 

 the fact that a great variety of conditions has called forth 

 great variation and induced many abnormalities without 

 evoking any indication of Tripsacum characters have caused 

 the first alternative to be dismissed. If the second alter- 

 native be adopted, we are compelled to look upon the 

 results of this cross as a special type of inheritance not 

 previously recognized. Hybrids showing a predominance 

 of the characters of the male parent have been described as 

 patroclinous, but in this cross and its successive progenies 

 no trace of the characters of the female parent has been 

 detected. No true hybriilization or conjugation between 

 the two nuclei appears to have taken place For this form 

 of false hybridization the name patrogenesis is proposed. 

 The term patrogenesis will also serve to place the phenom- 

 enon in proper contrast with parthenogenesis. This is 

 rendered appropriate by the occurrence of what appears to 

 be true parthenogenesis in Tripsacum when pollinated with 

 maize. 



